University of Nevada
Reno
A Survey of Soil Freezing on the
East Side of the Sierra Nevada
A thesis submitted in partial fulfillment of the
requirements for the degree of Master of Science
in Hydrology
by
Michael Francis Taylor in
June 1269 MINES library Thesis 3 L % c.3
The thesis of Michael Francis Taylor is approved:
University of Nevada
Reno
June 1969 i i i
ACKNOWLEDGEMENTS
I am particularly grateful to Dr. C. M. Skau, who served as my academic advisor and the co-leader of the project. He freely gave assistance and counsel throughout the duration of the study. His c ritic a l, but constructive, readings of this text are especially apprec i a ted.
I am also grateful to Dr. R. 0. Meeuwig, co-leader of the project, for his patient and helpful reading of this text.
Dr. John Sharp gave helpful assistance in his capacity as a member of my committee.
I would like to thank Mr. Doug Jager, Lecturer in Watershed
Management at the University of Nevada and Mr. Charles Raddon,
Forester for the Eagle Lake Ranger D istrict of the Lassen National
Forest, for accompanying me on some of my wanderings in the mountains during miserable weather and worse snow conditions; as well as Mr.
Wilbert H. Blackburn, Junior Range Ecologist, who freely volunteered his assistance in soil texture determinations.
I would also like to thank the Office of Water Resources Re
search of the Department of the Interior for funding the project and
the Intermountain Forest and Range Experiment Station for furnishing
and installing soil temperature measuring equipment near Slide Mountain.
I am grateful for the cooperation of the personnel of the Carson
Ranger D istrict of the Toiyabe National Forest, Milford Ranger D istrict of the Plumas National Forest and Mr. Troy Johnson of the Eagle Lake
D istrict of the Lassen National Forest. i v
I wish to thank University of Nevada students, Keith Cloudas,
Bruce Glinisky, Richard Jones and Rich Randall for their assistance during the past two winters.
Mrs. Lee Newman earned my gratitude for her fine typing of the final draft of the study.
My wife, Linda, deserves a special vote of thanks for her patience, encouragement, and endurance on the weekends that I spent
in the field.
M.F.T. V
TABLE OF CONTENTS
Page INTRODUCTION ...... 1
LITERATURE REVIEW ...... 3
Structural Forms of Frost ...... 5
The Effect of Forest Vegetation on Freezing ...... 6
Effect of Litter on Freezing ...... 7
Effect of Snow on Freezing ...... 9
Permeability and Moisture Content of Frost Types ...... 10
Moisture Movement in Frozen Soil ...... 11
OBJECTIVES AND SCOPE ...... 12
SOIL TEMPERATURE STUDY (1967-1968) ...... 16
Description of 1967~1968 Study Area ...... 16
Procedure for Winter of 1967-1968 ...... 17
Vegetation Classification (1967-1968) ...... 20
Results and Discussion of Winter of 1967-1968 ...... 22
North aspect forest plots ...... 2k
North aspect brush plots ...... 31
South aspect ridge (high) and slope (low) plots ...... • 35
East aspect forest plots ...... ^5
East aspect brush plots ...... 57
Contour terraced plots ...... 66
Burnt and disturbed plots ...... 73
Mount Rose Ski Area ...... 80
Road f ill ...... 80
Conclusions of Winter of 1967-1968 ...... 83 vi
Page SOIL FROST RECONNAISSANCE (I968-I 969) ...... 38
Description of 1968-1969 Study Areas ...... 88
Vegetation Classification (1968-1969) ...... 89
Procedure for Winter of 1 968-1 969 ...... 92
Results and Discussion of Winter of 1968-1969 ...... 95
Three period concept ...... 99
Period One (increasing frost occurrence) .. 99
Period Two (decreasing frost occurrence) .. 102
Period Three (spring snowmelt) ...... 109
Periodic study areas ...... 110
Observations over 7500 feet near Slide Mounta in ...... 110
Frost trends at Deans Ridge ...... 118
Frost trends at Constantia ...... 120
Frost trends at Pimentel Meadows ...... 125
The effect of soil frost on infiltration ...... 128
Hydrophobic soil observations ...... 130
Conclusions of Winter of 1968-1969 ...... 13’
LITERATURE CITED ...... 138
APPENDICES
1. Weekly soil temperature and snow depth of each temperature plot ...... l^l
2. Summary of soil temperature data collected at each temperature plot near Slide Mountain during winter of 1967-1968 ...... 1^9
3. Maps of winter of 1968-1969 study sites ...... 158
k. Soil frost transects (winter I968-I 969) ...... 166 vi i
LIST OF TABLES
Table Page
1. Physical description of Slide Mountain temperature plots ...... 18
2. Classification of winter of 1967-1968 temperature plots ...... 22
3. Maximum and average depth of snow and number of weeks from first trace of snow to last trace at each temperature plot during the winter of 1967-1 968 ...... 23
k. Areas studied during the winter of 1968-1969 ...... 88
5. Date and location of each transect run during the winter of 1968-1969 ...... 97
6. Summary of frost trends at all sites for winter of 1 968- 1969 ...... 98
7. Frost trends at Deans Ridge (1968-1969) ...... 119
8. Frost trends at Constantia (1968-1969) ...... 122
9. Summary of frost trends at Pimentel Meadows (winter of 1968-1969) ...... 127
10. Results of infiltration tests of frozen V i i i
LIST OF FIGURES
Figure Page
1. Location of soil temperature plots, Slide Mountain, Nevada. Winter, I 967- 1968 ...... }k
2. Winter of 1968-19&9 study areas ...... 15
3. Soil temperature graph of plot 1 ...... 25
4. Photograph of plot 1 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 26
5. Photograph of plot 2 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 27
6. Photograph of plot 6 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 28
7. Photograph of plot 7 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 29
8. Photograph of plot 37 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 30
9. Photograph of plot 8 and diagram of thermistor locations (scale: 1 inch to *4 feet) ...... 32
10. Photograph of plot 9 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 33
11. Photograph of plot 26 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 34
12. Soil temperature graph of plot 14 ...... 37
13. Soil temperature graph of plot 17 ...... 38
14. Soil temperature graph of plot 18 ...... 39 ix
Figure page
15. Photograph of plot 14 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 4o
16. Photograph of plot 15 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 41
17- Photograph of plot 16 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 42
18. Photograph of plot 17 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 43
19- Photograph of plot 18 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 44
20. Soil temperature graph of plot 11 ...... 46
21. Photograph of plot 30 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 48
22. Photograph of plot 32 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 49
23. Photograph of plot 3 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 50
24. Photograph of plot 4 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 51
25. Photograph of plot 19 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 52
26. Photograph of plot 20 and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 53
27. Photograph of plot 3^ and diagram of thermistor locations (scale: 1 inch to 4 feet) ...... 5^ X
Figure page
28. Photograph of plot 10 and diagram of thermistor locations (scale: 1 inch to k feet) ...... 5 5
29. Photograph of plot 11 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 56
30. Soil temperaturegraph of plot 13 ...... 58
31. Photograph of plot 5 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 59
32. Photograph of plot 12 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 60
33- Photograph of plot 13 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 61
3b. Photograph of plot 21 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 62
35. Photograph of plot 31 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 63
36. Photograph of plot 33 and diagram of thermistor locations (scale: 1 inch to b feet ...... 6b
37* Photograph of plot 36 and diagram of thermistor locations (scale: 1 inch to A feet) ...... 65
38. Soil temperature graph of plot 23 ...... 67
39. Typical cross section of a contour terrace ...... 68
bO. Photograph of plot 22 and diagram of thermistor locations (scale: 1 inch to b feet) ...... 69
^1. Photograph of plot 23 and diagram of thermistor locations (scale: 1 inch to b feet) 70 xi
Figure Page
k2. Photograph of plot 2k and diagram of thermistor locations (scale: 1 inch to k feet) ...... 71
kj>- Photograph of plot 25 and diagram of thermistor locations (scale: 1 inch to k feet) ...... 72
kk. Soil temperature graph of plot 27 ...... 7k
k5- Photograph of plot 27 and diagram of thermistor locations (scale: 1 inch to A feet) ...... 77
^6. Photograph of plot 28 and diagram of thermistor locations (scale: 1 inch to k feet) ...... 78
k~J. Photograph of plot 29 and diagram of thermistor locations (scale: 1 inch to k feet) ...... 79
^8. Photograph of plot 38 and diagram of thermistor locations (scale: 1 inch to k feet) ...... 81
kS. Photograph of plot 35 and diagram of thermistor locations (scale: 1 inch to k feet) ...... 82
50. View looking north from Interstate Highway 50 near the bottom of the Spooner Grade at 5200 feet. On January k, the left side of the gully (aspect S70E) was unfrozen while the right side of the gully (aspect N70W) was frozen ...... 103
51. South aspect Jeffrey pine-bitterbrush forest at the Constantia study site ...... 105
52. Mature mixed conifer forest at 6650 feet near the summit of Yuba Pass ...... 106
53. Snowbank patterns in a large brushfield 1 mile south of the Christmas Tree on Slide Mountain. Late April or early May 1S68 ...... 109
5k. Profile of transect SLT-A (November 1) ...... 112
55. Site of transect SLT-13 (January 18) ...... 113 X I I
Figure Page
56. Windswept ridge top at 8600 feet on Slide Mountain. Note the bare spots, thin snow cover and sparse vegetation ...... 116
57. Whitebark pine forest on a south slope at 10,100 feet in the Carson Range in Nevada. Mt. Rose (10,778 feet) is in the background. Ma rch 15, 1969 ...... 117
58. Deans Ridge study site ...... 1 18
59. North and east aspect Jeffrey pine-white f ir poles and sawtimber ...... 120
60. Dense stand of Jeffrey pine and white fir saplings and poles on a north slope ...... 121
61. Open, south aspect Jeffrey pine-bitterbrush community ...... 121
62. Pimentel Meadows study site ...... 125
63. Canyondam study site. General reconnaissance conducted in area indicated by arrow. U.S.G.S., Almanor, California, Quadrangle, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile ...... 157
6^. Coppervale study site. General reconnaissance conducted in crosshatched area. U.S.G.S., Westwood, California, Quadrangle, 15 minute series, contour interval kO feet, scale: 1 inch to 1 mile ...... 157
65. Susanville Summit study site. General reconnaissance conducted in area indicated by arrow. U.S.G.S., Susanville, California, Quadrangle, 15 minute series, contour interval kO feet, scale: 1 inch to 1 mile ...... 158
66. Deans Ridge study site. Arrow indicates location of transects. U.S.G.S., Fredonyer Peak, California, Quadrangle, 15 minute series, contour interval AO feet, scale: 1 inch to 1 mile ...... 158
67. Milford study site. Numbered arrow indicates location of transect. U.S.G.S., Milford, California, Quadrangle, 15 minute series, contour interval ^0 feet, scale: 1 inch to 1 mile ...... 159 X! I I
Figure Page
68. Constantia study site. General reconnaissance conducted in crosshatched area. Arrow indicates location of transects. U.S.G.S., Chilcoot, California, Quadrangle, 15 minute series, contour interval AO feet, scale: i inch to 1 mile ...... 160
69. Yuba Pass study site. General reconnaissance conducted in areas indicated by arrows. U.S.G.S., Sierraville and Sierra City, California, Quadrangles, 15 minute series, contour intervals 40 and 80 feet, scale: 1 inch to 1 mile ...... 160
70. Dog Valley study site. General reconnaissance conducted in areas indicated by arrows. U.S.G.S., Loyalton, California, Quadrangle, 15 minute series, contour interval AO feet, scale: 1 inch to 1 mile ...... 161
71. Sand Harbor study site. Arrow indicates location of transect. U.S.G.S., Carson City, Nevada, Quadrangle, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile ...... 161
72. Slide Mountain study site. Numbered arrows indicate location of transects. General reconnaissance conducted in area indicated by blank arrow. U.S.G.S., Mt. Rose, Nevada, Quadrangle, 15 minute series, contour interval AO feet, scale: 1 inch to 1 mile ...... 162
73. Spooner Summit study site. Numbered arrows indicate location of transects. General reconnaissance conducted in area indicated by blank arrow. U.S.G.S., Carson City, Nevada, Quadrangle, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile ...... 163
7^. Luther Pass study site. General reconnaissance conducted in area indicated by arrow. U.S.G.S., Freel Peak, California- Nevada, Quadrangle, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile ...... 16A X I V
Figure Page
75- Cloudburst Canyon study site. General reconnaissance conducted in area indicated by arrow. U.S.G.S., Freel Peak, Cal i forri i a-Nevada , Quadrangle, 15 minute series, contour interval 80 feet, scale: 1 i nch to 1 mile ...... ] Q/j
76. Bootleg Canyon study site. Arrow indicates location of transects and area of general reconnaissance. U.S.G.S., Fales Hot Springs, Ca1ifornia-Nevada, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile ...... 165
77- Pimentel Meadows study site. Arrow indicates location of transects. U.S.G.S., Fales Hot Springs, Ca1ifornia-Nevada , 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile 165 INTRODUCTION
Disastrous winter floods that stem typically from prolonged
1ow-intensity rains are not uncommon on the east slope of the
Sierra Nevada. The rain usually fa lls upon shallow snowpacks that often melt completely and contribute additional water to flood
runoff (Haupt, 1967). According to McGlashen and Briggs (1939) ,
floods occurred on the east side of the Sierras 9 times from 1861
to 1937. Young and Harris (1966) state that additional floods occurred in 1950, 1955, and 1963 -
Soil freezing has been repeatedly singled out as a primary cause of winter flooding (McGlashan and Briggs, 1939)* However,
literature on the subject is so scanty that it is not possible
to substantiate or refute this charge. The author knows of only
three soil freezing studies, in addition to the one just completed,
that have been conducted in the Sierras. One study was conducted by H. F. Haupt (1967) in Dog Valley, California, on the east side of the Sierras near Reno, Nevada. A soil freezing investigation at North Fork, California, at 2700 feet in the footh ills of the west slope of the Sierras was headed by H. W. Anderson (19^7) and a soil temperature and freezing study is presently being conducted by the Intermountain Forest and Range Experiment Station near
Slide Mountain and Clear Creek, Nevada.
Since the above studies were restricted to a handful of areas,
it was impossible to determine if soil freezing was a limited or widespread phenomenon in the Sierras during the winter. To eliminate
some speculation, the present study was undertaken to determine the extent, severity, and duration of soil freezing on the east slope 2
of the Sierra Nevada. Secondary objectives centered around the effect of hydrophobic soil on the freezing of soil and the effect of soil frost on infiltration. Much of the research was restricted
to the east side of the Sierras but some areas were also studied on
the west slope. LITERATURE REVIEW
There Is very lit t le readily obtainable literature that is
primarily concerned with soil freezing in the West. Studies
conducted in the Sierras by Anderson (19**7), Haupt (1967) and
the Intermountain Forest and Range Experiment Station have
previously been mentioned. In addition to these, Hale (1950,
1951) has studied soil freezing in the Cascade Range of Oregon
and Washington. A search of the Dr. James E. Church Collection
of the University of Nevada resulted in the discovery of two
passing references to soil frost in the Carson Range to the east of Lake Tahoe. Because of the lack of regional literature, the
author was forced to rely on the results of studies conducted
in the East and Northeast to gain some inkling of what factors
may be expected to control soil freezing in the Sierras.
A study of soil freezing should begin with an understanding of seasonal and diurnal changes in soil temperature. The upper
layer of soil is supplied with heat during the summer, which is
given off again during the winter. The primary heat supply is
determined by the incoming short-wave radiation from the sun, while the heat emission is mainly determined by the outgoing long wave radiation from tne earth (Janson, 196*0.
During the summer, the surface of the soil is heated during
the day by incoming radiation. Most of this heat is then lost, partly through convection to the colder surrounding air, while
the remainder of the radiated heat is transmitted into the ground by conduction. In the winter the circumstances are reversed, so 4
that the total amount of heat transmitted during 24 hours brings about an equivalent cooling of the earth. Since the heat supplied is equal to the heat emitted during the year, a balance
is obtained. The heating and cooling of soil during the winter
is complicated by the insulating effect of snow and litter.
According to Anderson (.1947) low air temperature is the primary cause of soil freezing. Once low a ir temperatures allow
freezing, Janson (1964) indicates that the depth of freezing depends on: (1) duration and magnitude of the air temperature below 0° Centigrade, (2) the mean annual temperature of the area,
including the quantity of heat that has been transmitted to the soil during the previous summer, (3) the occurrence and depth of snow, (4) the thermal conductivity of the soil, (5) the specific heat of the soil, and (6) the density and moisture content of the soil. Chow (1964, p. 10-47) states that vegetation also affects so i1 freezi ng. Structural Forms of Frost
Several rather distinct structural forms of soil frost have been observed. These forms are caused by a complex of factors such as texture, structure, porosity, and moisture content of the soil; rate and duration of freezing; type and depth of humus and
litter; and depth of snow (Pierce, Lull and Storey, 1958).
The author used the criteria developed by Post and Dreibelbis
(19^2) to recognize concrete, granular (honeycomb), and stalactite frost types. These, plus porous concrete and frozen litte r, are the only types of frost that have been observed in the Sierras by the author. To save space in some tables, frost type w i11 be referred to by number rather than by name.
Concrete frost (1) consists of many very thin ice lenses, small crystals, and extremely dense structure. It usually occurs
in soils previously frozen and thawed or in soils settled by heavy rain, and is found most often in bare so ils or in areas with a sparse vegetal cover. All pores are fille d with ice and it is
impossible to break a clod by hand.
Porous concrete frost (2) is sim ilar to concrete frost but is not as dense as concrete frost and sometimes may be broken by hand.
Pore space is occupied by approximately equal amounts of air and water. The water may be in both the frozen and liquid states. At times it may be impossible to distinguish concrete from porous concrete frost.
Granular frost (3) consists of small frost crystals intermingled with the soil particles. These crystals aggregate around the soil particles, but remain separated from each other. Clods are easily 6
broken (Trimble, Sartz and Pierce, 1958). Small ice crystals may
be found on the bottom of soil particles and rock fragments.
Stalactite frost (*0 is characterized by small, vertical icicles
that join heaved surface particles to the main soil mass. According
to Geiger (196$, P- '75), the fir s t 6 inches of soil below the surface
play the greatest part in producing stalactite frost. The water
content of the soil below 12 inches apparently has no effect. Frost
heights of 6 inches above the soil surface are common, while heights
of up to 20 inches have been recorded but are rare.
Brink, et al. (1967) indicate that stalactite frost develops on
bare or thinly vegetated soil on frosty nights after recent rain or
melting of snow. As the air temperature near the soil surface drops
below freezing, ice needles several inches in height grow from the wet soil to enclose and lift stones, soil particles and duff.
Frozen litte r (5) is simply a litte r layer that forms a
coherent mat when water in the litte r freezes. Frozen litte r
probably loses lit t le of its capacity to accept rain or water from melting snow.
The Effect of Forest Vegetat ion on Freezing
Many investigators have studied the effects of forest vegetation on frost type, thickness and duration of freezing. Anderson (19^7) states that the effectiveness of the forest in modifying freezing has been found to vary with the type of cover, such as evergreen versus deciduous, and with the amount and time of occurrence of snow cover. Forest cover has been found to reduce the depth of freezing and delay the date of the first occurrence of frost in the soil. 7
Hale (1950) found that permeable frost was usually restricted
to small areas during the winter of 19^+9“ 1350 in the ponderosa pine
{Pinus ponderosa) type on the east slope of the Cascades of Washing
ton and Oregon. Impermeable frost was found near the base of trees
and on windswept areas where the snow melted early and the bare,
moist soil was exposed to low temperatures at night. Hale (1951)
found in a study near LaGrande, Oregon, that at no time during the
entire observation period were there extensive areas of impermeable
frozen ground. Stalactite frost occurred only at the beginning and end of winter and that, by the middle of April, all soil had thawed.
Soil depth and drainage characteristics appear to be less impor
tant than aspect and cover in determining frost occurrence. Resuits of a study by Hale (1950) showed that impermeable (concrete)
freezing was observed least often on south slopes covered with either open stands of ponderosa pine or grass. Concrete and granular frost occurred in the ponderosa pine-grass vegetative type only after the snow had melted in March. In another study, Hale (1951) found that soil under lodgepole pine (Pinus murrayana) remained frozen throughout the winter, while concrete frost was spotty and of lit t le extent in soil under ponderosa pine.
Effect of Litter on F reez i ng
The thickness and character of duff are important factors in determining the extent and time of frost occurrence in the soil, and,
in part, for the maximum depth to which the frost penetrates (Kienholz,
19*»0) . 8
According to Li (1926), the effect of the forest in raising the minimum surface temperature is due mainly to the presence of litter, while the trees exert little or no influence. However, the maximum surface temperature is influenced by the forest canopy with the litte r having lit tle effect. MacKinney (1929) found that litte r cover raised both the mean maximum and mean minimum surface soil temperature in the autumn and lowered them in the spring.
For deeper soil temperatures, litte r raised the average temperature for all seasons. The diurnal range of the surface soil temperature is diminished appreciably by litter, but beneath the surface, this effect is not so pronounced.
From October 1926 to April 1927, MacKinney (1929) studied soil temperature in a mixed plantation of red pine (Pinus resinosa) and white pine (Pinus s tro b u s ) near New Haven, Connecticut, and found that the character of the frozen soil was influenced by the depth of litter. The soil on a bare plot froze solidly to a maximum depth of 8 inches, and the pore spaces were practically fille d with ice. On the other hand, the frozen soil beneath a litte r cover of
2 inches of pine needles and a thin layer of humus froze to a maximum depth of 5.8 inches and was porous and loose. In the litter covered soil, the ice formed around the soil particles leaving the spaces between the particles open.
During winter rains and thaws the water soaked into the soil of the litter-covered plot and percolated to lower depths. On the bare plot, the water ran off at such times, due to the non-porous character of the frozen so il. On the litte r covered plot, although 9
the litte r layer froze, the soil beneath the litte r did not show signs of freezing until approximately one month after frost appeared in the bare soil.
Effect of Snow on F reez i ng
Many workers have noted that snow acts as an insulator and prevents or retards soil freezing. According to Anderson (19^7),
Beskow (1935) found that the insulating effect of snow is due to
its low heat conductivity which is, for uncompacted snow, only about one-terith of that of moist so il. The effectiveness of snow in preventing freezing of the soil was found to depend on the air temperature, snow depth and density, and on the temperature gradient in the snow and in the soil beneath.
According to Hale (1950, 1951), snow depth was found to be
influenced by aspect and cover and appeared to be an important factor in lim iting the occurrence and depth of impermeable freezing. Snow on north slopes prevented freezing while soil froze on bare south slopes.
Hart (1963) found that average frost depths did not vary a great deal between cover types during the period of highest frost incidence near Plymouth, New Hampshire, in I960. The frost uni formity suggested that, once snow cover was established, the depth of frost was governed more by snow depth than by cover type. Major differences in frost depth developed during periods of lit t le or no snow cover.
MacKinney (1929) in work near New Haven, Connecticut, found that the additional insulating properties of litter beneath a snowpack, held the maximum and minimum soil temperatures at all 10
depths about one degree higher during the winter.
Anderson (19^7) found that frozen soil tends to thaw from the bottom upward under a cover of snow. In the absence of snow, frozen soil tends to slowly thaw from both the top and bottom. The rate of thawing is somewhat different depending on the relative rates of heating of the surface and the bottom of the frozen layer.
Permeab i 1i ty and Moisture Con tent of F rost Types
The American Society of Civil Engineers Hydrology Handbook (19*t9> p. h0) states that when soils of low moisture content freeze, they become granulated and more permeable than wet so ils. According to
Krumbach and White (196*0, the growth of ice crystals causes displacement and bulking of the so il, thus increasing porosity, decreasing bulk density, and maintaining a condition in which further moisture accretions occur until the soil moisture eventually may be above the unfrozen capacity of the soil. Since the process involves displace ment of soil particles by crystals, pore space is sometimes created faster than it is filled by available water. This circumstance pro bably accounts for the large amount of unoccupied pore space in some frozen soil, even when moisture content is above prefreeze saturation
(Megahan and Satterland, 1962).
Stoeckeler and Weitzman (I960) found that moisture content decreased from concrete, porous concrete, partly frozen to unfrozen soil. Weitzman and Bay (1963) found that in a red pine stand, moisture content or porous concrete frost ranged from 12.3 to 21.6 percent, and moisture content of concrete frost ranged from 27.A to *i5.1 percent. 1 ]
Moi sture Movement i n Frozen So i 1
During the winter, when soil freezing is actively progressing, it may be observed that soil moisture will actually decrease with increasing depth into the soil. Taber (1930) indicates that as^ water in the surface layer of soil freezes, the soil moisture tension greatly increases, creating a tension gradient. Because of this gradient, additional water moves up from the wet so il, where water is held at low tensions, into the freezing layer where it is held at high tensions. As the upward moving water freezes, the capillary tension continues.
According to Ferguson, Brown and Dickey (196^0, the amount of water movement depends on available soil water, temperature of the frozen zone, length of frozen period, and physical properties of the soil. Water moved to the frozen zone is subject to evaporation since it is close to the surface.
Taber (1930) discussed the mechanics of ice crystal growth and heaving in so ils, and emphasized that excessive heaving is dependent on water moving upward through the soil to the zone of freezing, and cannot be accounted for by the change in volume of water upon freez i ng. OBJECTIVES AND SCOPE
The paucity of prior knowledge concerning soil freezing
dictated that this present study should be conducted as a first
approximation of soil freezing in the Sierras. To achieve this
goal, the study was structured around two basic questions. First,
what effect does elevation, aspect, vegetation and snow depth have
on soil temperatures in the area of Slide Mountain during the
winter? Second, how does elevation, aspect, vegetation and snow
depth affect the occurrence, longevity, depth and type of frost
that may occur in the Sierras?
Field work was divided into two phases. During the winter of
1967_1968, a soil temperature study was conducted between 5900 and
8400 feet elevation in the area of Slide Mountain, approximately 20
miles south of Reno (Figure 1). Knowledge obtained during the
winter of 1967-1968 was used to conduct, during the following
winter, a general reconnaissance of freezing of granitic soils on
the east side of the northern Sierras (Figure 2). Study areas
ranged from Bridgeport, California (100 airline miles south of Reno)
to Susanville, California (85 airline miles north of Reno) and from
4300 to 10,100 feet in elevation.
The objectives of the project were to study: (1) spatial
distribution of frost and its relationship to aspect, elevation,
latitude, vegetation and snow depth, (2) various types of frost
encountered in the Sierras, (3) average and maximum depths of the various types of frost, (4) relationship of time of year to the
type and occurrence of frost, (5) infiltration capacity of various types of frost, (6) effect of hydrophobic so ils on soil freezing, and (7) effect of time of year, aspect, vegetation and snow depth on soil temperature in the area of Slide Mountain. 14
coyt Cj
>a CteeKV ^ 'f*
' -iiliu \\&ijjii/j)ll-i\ 1 \ r ^ ^ soil temperature plots, Slide Mountain, Nevada /■ o 15
CALIFORNIA NEVADA
LUTHER PASS Woodfords "... O q D ' N CLOUDBURST \ \ CANYON \ SCALE X 0 10 30 50 X. X miles BOOTLEG.CANYON N \ O \ PIMENTEL'MEADOWS \ O \ LEGEND Bridgeport \ O STUDY SITE \ \ □ COMMUNITY X Monoo Lake v. ^ y
FIGURE 2 .—WINTER OF1968-19G9 STUDY AREAS SOIL TEMPERATURE STUDY (1967-1968)
Descri pt i on of 1967"1968 Study Area
During the winter of 1967- 1968, soil temperatures were recorded in the Jones, Galena, and Browns Creek watersheds near Slide
Mountain. Soil temperature plots in the Jones and Galena Creek watersheds ranged in elevation from 5900 to 6A50 feet, while plots in the Browns Creek watershed ranged from 6600 to 8A00 feet. A variety of vegetative types on north, south and east aspects were sampled. Individual plot slopes ranged from 0 to 50 percent.
Precipitation in the area fa lls mostly as snow and has been estimated to be from 20 to 30 inches per year (Townsend, 1966, p. k) .
Vegetation consists of brushfields dominated by snowbrush (Ceanothus velu tin u s) and greenleaf manzanita (Aretostaphylos patula ) laced with stands of Jeffrey pine (Pinus jeffreyi) and white f ir (Abies conoolor) of various ages and densities.
Soils of the area were derived from granitic and andesitic rubble and are well drained. They are generally deep, except in the vicinity of rock outcrops, and have varying amounts of slightly weathered stones and cobbles. The soil is readily susceptible to erosion since the soil particles are coarse and poorly aggregated
(Hussai n, 1968 , p. 11). 17
Procedure for Winter of I 967-I 968
During the summer of 1967, 38 temperature plots were installed
in the area of Slide Mountain (Table 1). Twenty-six of the plots
are located along a spur road that runs south from the Mount Rose
Highway along the 6950 foot contour. The remaining 12 plots are
adjacent to the Mount Rose Highway.
Each plot consists of five General Electric 1D203 thermistors.
Three thermistors (numbered 1 through 3) were located at the s o il-
litte r interface or at a depth of one-half inch if no lit te r was
present. A fourth thermistor (numbered 14) was placed approximately
6 inches below the soil surface, and a fifth thermistor (numbered 5) was placed approximately 2k inches below the soil surface. The fifth
thermistor of 10 plots was placed at depths ranging from iA to 21
inches below the surface because rocky soil prevented placing them deeper.
The thermistors were placed in the ground with a minimum of disturbance. Any disturbed litter was replaced in as near a natural condition as possible. Wires from each thermistor were run under ground to a central terminal on a metal fence post. Thermistor resistances were measured with a V/heatstone bridge. 18
Table 1. Physical description of Slide Mountain temperature plots
2 j 3/ Plot Aspect S1 ope Elevat ion—^ Vegetat ion— Basal Area— ^ (percent) (feet) per acre (feet ) 1 N02W 1R 6920 Wf 230 2 N02W 15 6920 Wf 300 3 N3^E 29 6880 Wf 180 b N*t8E 30 6880 Jm 200 5 S85E 25 6880 Ms 50 6 NOSE 17 6930 Wf 150 7 N27E 26 6930 Wf 250 8 Nl 0W 28 6920 Ms 10 9 N05W 30 6910 Ms 10 10 S53E 17 6970 Jmo 170 11 S55E 16 6970 Jmo 180 12 S59E 20 6970 Mz 30 13 S59E 20 6970 Ms 20 1^ S08E 15 6960 Jmo 1 10 15 S08W 1 b 6960 Jmo 90 16 SObE 19 6950 Ms bO 17 S02W 17 6950 Ms 50 18 S02W 17 6950 Mz 30 19 N 51 E 15 6920 Jmo 190 20 N 51E 15 6910 Jmo 220 21 East lb 6920 Ms 10 22 East 02 6930 Ter 0 23 East 01 6930 Ter 0 2b S05W 03 6980 Ter 0 25 N06W 03 6980 Ter 0 26 N06W 20 6980 Ms 0 27 S58E 06 5880 Jb 175 28 N70E 05 5960 Jbf 0 29 NA8E 08 6100 Jbf 0 30 S 61 E 05 6100 Jy 265 31 N^8E 12 62^0 Ms 50 32 N53E 10 62A0 Jm 260 33 N68e 25 6 ^ 0 Ms 0 3^ N35E 19 6600 Jm 260 35 South b8 6800 Road F ill 10 36 N56E 26 71^0 Sb 10 37 N26E 23 7H 0 Jm 230 38 N50E 08 8A00 Red f i r 80
W Elevations from U.S.G.S., 15 minute, Mount Rose, Nevada quadrangle map 2/ Symbols explained in following section on vegetation (page 20) 3/ Determined by Relascope 19
Soil temperatures were recorded, with few exceptions, once
a week from September 22, 1967 to May 2A, 1968. Snow depth, to
the nearest half-inch, was measured near the metal fence post at
the same time that temperatures were recorded. A disadvantage of this practice of snow measurement was that the depth of snow over the thermistors was not always the same as that in the area of the metal pole. 20
Vegetation Classification (1967-1968)
Perusal of the vegetation surrounding each temperature plot
indicated that the plots fell into 10 readily distinguishable groups.
When forest trees were growing on or near a plot, the classification of that plot depended upon the age and density of the trees and whether brush was associated with the trees. When no trees were present, the dominant species of brush determined the c la ssifica tio n .
Several different types of disturbance were also recognized. However, the type of disturbance determined the cla ssifica tio n while associated trees and brush were of secondary importance. Each plot was placed
in one of the following keyed categories:
(1) Jmo Jeffrey pine-mature and open. Gre'enleaf manzanita
or snowbrush or both growing between and under
small Jeffrey pine sawtimber or poles.
(2) Jy Jeffrey pine-young. Jeffrey pine saplings and poles
with a closed canopy. Brush usually not present.
(3) Jm Jeffrey pine-mature. Small Jeffrey pine sawtimber
or poles with a closed canopy and no brush cover.
(**) Jb Jeffrey pine burned. Small Jeffrey pine sawtimber
burned by a hot ground fire.
(5) Jbf Jeffrey pine burned and furrowed. Previous forest
killed by fire. After all trees were removed,
Jeffrey pine seedlings were planted in controur
furrows.
(6) Hz Greenleaf manzanita. Open or closed pure stand of
green leaf manzanita. 21
(7) Sb Snowbrush. Open or closed pure stand of snowbrush.
(8) Ms Manzanita-snowbrush. Any site dominated by a
mixture of greenleaf manzanita and snowbrush.
(9) Wf White fir. Closed forest dominated by white fir.
Jeffrey pine may occur as a subordinate.
(10) Ter Terraced. A brushfield with contour terraces, 8
to 10 feet wide, cut into slope at 5 foot intervals.
Jeffrey pine seedlings were planted in the center
of terraces.
Adjectives used to modify the sizes of forest trees were taken from Dilworth (1965, p. 182). According to Dilworth (1985), seedlings and saplings range from 0 to 5 inches in diameter at breast height, poles range from 5 to 11 inches in diameter at breast height, and small sawtimber ranges from 11 to 21 inches in diameter at breast height and large sawtimber is greater than 21 inches in diameter at breast height. 22
Resu 1 ts and Pi scuss ion of VI i nter of 1 967~ 1 968
The 5 temperatures recorded every week at each plot were plotted against time. Each of the resulting 38 graphs showed declining temperatures during the fall and steady or rising temperatures during the winter and rising temperatures in the spring. Differences in vegetation, snow depth, disturbance and sometimes elevation caused irregularities in the basic concave shape of a graph. Because plots with similar environments had similar shaped graphs, it was possible to arrange the soil temperature graphs into readily distinguishable groups. Table 2 shows the plot groups that will be discussed in the following section and the specific plots that fell into each group.
Table 2. Classification of winter of 1967~1968 temperature plots
Plot Classification Plot number Average 2k inch temperature (degrees Fahrenhe i t) north forest 1, 2, 6, 7, 37 37.2 north brush 8, 9, 26 35.^ south ridge (h i gh) 1*», 15 37.8 south slope (1 ow) 18, 17, 18 38.7 east forest (1 ow) 30, 32 39.2 east forest (h i gh) 3, *», 19, 20, 3A 37.5 east forest (bare) 10,11 38.2 east brush 5, 12, 13, 21 , 31 37.7 33, 36 terraced 22, 23, 2k, 25 36.1 bu rned 27, 28 , 29 38.7 road fill 35 kk.S Mt. Rose Ski Area 38 3^.3 23
Table 3. Maximum and average— depth of snow and number of weeks from firs t trace of snow to last trace at each temperature plot during the winter of 136’/-1968 // Weeks Weeks of // snow Plot // Weeks Weeks of // snow Average Depth (in Maximum Depth Maximum (in Plot Depth Maximum (in Average Depth (in
1 54 31 .5 22 21 49.5 31 ‘ 12/ 18 2 51 31 .0 21 22 49 29.24/ 18 3 33.5 19.2 19 23 55 31 -3§y 19 4 41 22.3 19 24 20 13.6^ 16 5 64 40.8 19 25 53 31 .4— 20
6 49 28.5 18 26 41 25.2 19 7 54.5 31.7 21 27 10 4.9 15 8 64 42.1 21 28 9 4.1 14 9 60 38.0 21 29 20 7.9 16 10 13 5.2 16 30 23.5 13.0 16
11 15 7.7 16 31 41 22.0 16 12 38 23.4 16 32 26 12.2 16 13 46 26.8 16 33 50 30.2 17 14 6 1.3 16 34 41 23.1 17 15 10 3.0 16 35 14 3.5 14
16 36.5 17.3 15 36 64 40.0 18 17 30 18.7 15 37 41 22.3 23 18 26.5 15.5 15 38 73 43.8 26 19 24 11 .6 17 20 27 14.2 17
J/ Average of all weekly observations starting with the f ir s t trace of snow on the plot and ending with the last trace of snow on the plot in the spring. Snow depths were not measured on 12-30-67 and 4-12-68. Zero and trace observations were both given a value of 0 and were used in computing average depth.
2/ Snow depth measured at center of terrace. All of the temperatures recorded during the winter appear in
Appendix 1. The soil temperature graphs that appear in the text were chosen because they are representative of a specific group or display significant trends.
North aspect forest plots
During the winter, north slope forest plots (Figures 4-8) were characterized by long term steady soil temperatures beneath a deep snowpack and a very small difference in soil temperature between the surface and a depth of 6 inches. For example, there was very lit t le change in soil temperatures at all depths at plot 1 from December 1,
196'/ to May 10, 1968 (Figure 3). During this time, snow depth at plot 1 averaged 31.5 inches with a maximum depth of 54 inches.
Soil temperatures ceased to decline and in some cases increased at north aspect plots when the winter snowpack was established.
Freezing temperatures were rarely encountered and none were recorded after late December. On November 27, 1967, a few days before the first large snowstorm of the winter, up to 3 inches of granular frost was observed in the area of plots 6 and 7. This frost probably thawed quickly after the first heavy snowfall on December 1.
Figure ^ .--Photograph of plot 1 and diagram of thermistor locations (scale: 1 inch to 4 feet). Figure 5 •— Photograph of plot 2 and diagram of thermistor locations (scale: 1 inch to feet).
*v f y Ux; f t
K - - f BBT y j BBS
411 \ 4 \ -----\ t-----
3 t 1 — i ► 2 -----(9----- □p ° LE
Figure 7 .--Photograph of plot 7 and diagram of thermistor locations (scale: 1 inch to k feet).
31
North aspect brush plots
Conditions observed at north aspect brush covered plots
(Figures 9-11) were almost identical to those found on north aspect forest plots. Freezing temperatures were recorded from late November to late December. The only apparent difference between forest and brush covered north aspect plots was that temperatures at a depth of 24 inches were lower on brush covered plots than on forest plots. Average snow depth on north aspect forest plots ranged from 28.5 to 31.7 inches (average depth 29.0 inches) while snow depths of north aspect brush plots ranged from
25.2 to 42.1 inches (average depth 35.1 inches).
On November 27, granular frost from 1 to 5 inches thick with an average depth of 3 inches was found near plots 8 and $. The frost was found in small patches; the majority of the area was not frozen. The 5 inch depth of frost occurred in bare soil on a trail through the brush. Because of this, it cannot readily be compared with frost found under the litter of north aspect forest plots.
It may be concluded that north aspect forest and brush plots may be distinguished by long-term steady soil temperatures beneath a deep snowpack, patchy soil frost at the beginning of winter and no freezing temperatures after late December. Figure 9 .'•-Photograph of plot 8 and diagram of thermistor locations (scale: 1 inch to k feet). Figure 10.--Photograph of plot 9 and diagram of thermistor locations (scale: 1 inch to h feet). 3A
_TC P <)F CU r
1 4 F 1 A
/ |.3 4 .2 /
PO LE
TC IP < F|L L
Figure 11.--Photograph of plot 26 and diagram of thermistor locations (scale: 1 inch to h feet). 35
South Aspect R i dge (high) and S 1 ope ( low) Plots
All south aspect plots (Figures 15_19) were near 7000 in elevation and each had approximately the same slope. Figure 12 shows the soil
temperature graph of plot 1*4. Temperatures of plot 15, adjacent to
1*4, were nearly identical. Both plots are in the Jeffrey pine-mature open vegetative type on a ridge top that quite often is blown nearly clear of snow. At plot 1A and 15, freezing temperatures were recorded from December 8 to 23, 1967- During this time, air temperatures were unusually low and snow depths ranged from 1 to 2 inches over the plots.
On December 15, a maximum of 6 inches and an average of 3 inches of granular frost were recorded in the area of plot 15. It was also noted that soil moisture decreased from the surface downward.
Throughout the winter, soil temperatures fluctuated with changes
in weather to at least 18 inches. Freezing was limited at these plots because the ridge is open to the s>uth and consequently received enough solar radiation to nearly prevent soil freezing.
Plots 16, 17 (Figure 13), and 18 (Figure 1*0 are sheltered from the wind and are slig h tly below plots 1 ** and 15. No freezing temperatures were reported at these lower stations throughout the entire winter. Snow depths at these lower stations were many times deeper than those over plots 1*4 and 15. Snow depths averaged 17-3,
18.7 end 15.5 inches over plots 16, 17 and 18, while the average depths of snow over plots 1*4 and 15 were 1.3 and 3.0 inches.
Soil temperatures of plot 16 and 17 continued to decline after a snow cover had been established. These plots are covered with a mixed stand of greenleaf manzanita and snowbrush. Plot 18 has 36
no litte r cover and the thermistors are near the bare soil surface.
In contrast to plots 16 and 17, soil temperatures of plot 18 did
not drop, but remained relatively uniform after a snow cover had
been establi shed.
There is more brush and fewer trees on the lower plots, but
the aspect, elevation and slope of plots 1 ^ through 18 are all
similar. The major environmental difference is snow cover.
It may be concluded from observations made on south slopes
that snow depth was very shallow near the ridge tops where wind
blew practically all snow away, and relatively deep on sheltered slopes below the ridge tops. Freezing fluctuated with weather changes throughout the winter near the ridge tops, while in more sheltered areas, soil temperature fluctuation was very sligh t and no freezing temperatures were recorded. Degrees Fahrenheit Sept; -Oct.- •Nov. • Dec.- ■ Jant-
Figure 13 .—Soil temperature graph of plot 17. Degrees Fahrenheit iue 4.- 1 eprtr gah f lt 18 plot of graph temperature i1 o .--S 14 Figure 3 J Th erm!stor V-D K j J ki a ; f ND
<
/1
PO _E *
Figure 15.--Photograph of plot 14 and diagram of thermistor locations (scale: 1 inch to 4 feet). 41
• 4
• 1 <>2 1>5
,3
N
TRI : e g p
F i gure 16.--Photograph of plot 15 and diagram of thermistor locations (scale: 1 inch to 4 feet). 42
Ml y i' ii.ii
Figure 17.--Photograph of plot 16 and diagram of thermistor locations (scale: 1 inch to 4 feet). 1 |
4 f N 5 T
PO LE __4
Figure 18.--Photograph of plot 17 and diagram of thermistor locations (scale: 1 inch to 4 feet). kk
Figure 19.--Photograph of plot 18 and diagram of thermistor locations (scale: 1 inch to k feet). ^5
East aspect forest plots
East facing forest plots (Figures 21-29) were characterized
by a small difference in fall temperatures between the surface
and 2h inches and a decline in temperatures after the snowpack
had been established. However, there were two exceptions: (1)
temperatures increased slig h tly at plots k and 3^ after the fir s t major snowfall, and (2) temperatures at plots 30 and 32 increased
for one week after the first major snowfall and then gradually decli ned.
Plots 30 (6100 feet) and 32 (62^0 feet), both low elevation east aspect forest plots, were warmer than the other east facing
forest plots. No freezing temperatures were recorded at the lower plots where the snow averaged 13.0 and 12.2 inches in depth during
the winter. However, freezing temperatures were recorded at least once at A of the 5 high elevation plots where snow depth at all plots averaged 18.1 inches. Freezing temperatures were recorded at plot 19 (high elevation forest) between December 15 and March 22.
The high elevation east aspect plots ranged from 6600 to 6920 feet
in elevation.
Soil freezing at plot 19 occurred when the snow cover was between 10 and 15 inches deep but no freezing was reported when the snow depth exceeded 20 inches. Freezing occurred a second time when the snowpack shrank to a depth of 7 inches.
Plots 10 and 11 (Figure 20) are representative of east facing forest plots near a ridge top where the snow cover is kept very thin by wind. Snow depth averaged 5.2 inches on plot 10 and 7.7
inches on plot 11. Freezing conditions were recorded from mid- Degrees Fahrenheit 47
December to mid-February at these plots. Plots 14 and 15 were within 200 feet of plots 10 and 11. The difference in frost occurrence between these plots is probably a function of solar radiation and not one of snow cover or vegetation. Plots 10 and 11 face east and thus receive less solar radiation than the more southerly plots 14 and 15.
Granular frost approximately 3 inches thick was often encountered during December and January near plots 10 and 11.
Maximum frost depth was recorded on January 22 when 4 inches of porous concrete over 2 inches of granular frost was found near plot 10. Freezing temperatures were reported at plots 10 and 11 from December 15 to February 16. Soil temperatures responded quite rapidly to changes in weather conditions. The lowest temperatures were recorded at both plots on December 15. Figure 21.“-Photograph of plot 30 and diagram of thermistor locations (scale: 1 inch to b feet). ^9
Figure 22. Photograph of plot 32 and diagram of thermistor locations (scale: 1 inch to k feet). Figure 23.--Photograph of plot 3 and diagram of thermistor locations (scale: 1 inch to ^ feet). 51
Figure 2k.--Photograph of plot k and diagram of thermistor locations (scale: 1 inch to 4 feet). Figure 25.--Photograph of plot 19 and diagram of thermistor locations (scale: 1 inch to 4 feet). 53
1 W i►4 3 4 P ° LE 9 Figure 26.--Photograph of plot 20 and diagram of thermistor locations (scale: 1 inch to feet). 54 Figure 27-— Photograph of plot 34 and diagram of thermistor locations (scale: 1 inch to 4 feet). 55 Figure 28. Photograph of plot 10 and diagram of thermistor locations (scale: 1 Inch to k feet). 56 w <>4 ,3 2 V f " A • LE 4 1 P|P C Figure 29•--Photograph of plot 11 and diagram of thermistor locations (scale: 1 inch to b feet). 57 East aspect brush plots Unlike the east aspect forest plots, temperatures at east aspect brush plots (figures 31 -37) did not continue to decline after they were covered with snow. Figure 30 (plot 13) is representative of east aspect brush plots. Four of the 7 brush plots froze but 3 of these plots froze only on November 27. Average snow depths ranged from 22.0 to ^0.8 inches on the brush plots while snow depths on the forest plots ranged from 5.2 to 23.1 inches. Several inches of granular frost were found in a bare opening between clumps of brush on November 29 at plot 31. In conclusion, the east aspect forest plots fell into three groups: (1) the east aspect high elevation forest plots froze several times while (2) the east aspect low elevation forest plots did not freeze, and (3) east aspect forest plots near a windswept ridge top froze more often than the high elevation forest plots. Snow depths over east aspect brush covered plots were greater than snow depths recorded over east aspect forest plots. Freezing at east aspect brush plots was less severe than a high elevation west aspect forest plots and more severe than freezing at east aspect low elevation forest plots. Degrees Fahrenheit F gr 3.- l eprtr gah f lt 13. plot of graph temperature il o 30.--S igure 59 1 — 1 9— 2 a . (r <>4 p ° LE 4 V— ------< t r 5 Figure 3 1 .--Photograph of plot 5 and diagram of thermistor locations (scale: 1 inch to b feet). Figure 32.--Photograph of plot 12 and diagram of thermistor locations (scale: inch to k feet). Figure 3 3 .— Photograph of plot 13 and diagram of thermistor locations (scale: 1 inch to 4 feet). Figure 35.— Photograph of plot 31 and diagram of thermistor locations (scale: 1 inch to h feet). Figure 36.--Photograph of plot 33 and diagram of thermistor locations (scale: 1 inch to b feet). ,3 M 1— ( ► 5 4 ----i f 1f PO LE 2 66 Contour terraced plots Figure 38 (plot 23) is a typical soil temperature graph of a terraced plot (Figures ^0-^3). There is essentially no differ ence in the shape of the soil temperature curves of east (plot 22 and 23), south (plot 2k) and north (plot 25) aspect plots. It is quite evident from Figure 38 that there was a steep surface soil temperature gradient from the outer edge of the fill slope to the inner cut slope of the terrace during snow free periods. This gradient was reversed during periods when there was a snow cover. However, the gradient was very sligh t at these times. When snow covers a terrace, its depth increases from the outer to inner edge of the terrace. Soil temperature also follows this same gradient, increasing as snow depth increases. There was no change in soil temperature after the first major storm of the season. On the east and south aspect plots, sub-freezing temperatures were recorded only on the outer edge of the terrace. The outer edge of a terrace has the shallowest snow depths and is the first area to become bare during periods of snowmelt The outer edges of the terraces of the east facing plots were frozen from the end of November to January 12. The south aspect plots froze from the end of November to February 16. On November 27, 2 inches of granular and 6 inches of porous concrete frost were recorded on plot 25 and 5 inches of granular frost were found on plot 23. Figure 38 .— Soil temperature graph of plot 23. 68 Porous concrete frost was often observed on the outer fill slope of plot 2b. At plot 2b, on January 22, no frost was found under 16 inches of snow but 3*5 inches of concrete frost was found under 2 inches of snow. Saturated thawed soil was found where the surface was bare of snow. During the winter, there was a slight increasing soil tempera ture gradient from the outer to inner edge of a terrace. Snow depth increased from the outer to inner edge of a terrace. Soil freezing frequently occurred at the outer edge of a terrace. Figure 39.--Typical cross section of a contour terrace. Figure ^ 0.--Photograph of plot 22 and diagram of thermistor locations (scale: 1 inch to ^ feet). 70 11. n * ' i .ti Figure 1 . Photograph of plot 23 and diagram of thermistor locations (scale: I inch to h feet). Figure 42.--Photograph of plot 24 and diagram of thermistor locations (scale: 1 inch to 4 feet). 72 Figure 43•--Photograph of plot 25 and diagram of thermistor locations (scale: 1 inch to 4 feet). 73 Burnt and d i sturbed p1ots Three soil temperature plots were placed within the Galena Creek burn of 1966 (Figures *»5-^7). Plot 27 is in a stand of mature Jeffrey pine that was burned by a hot surface fire. Plots 28 and 29 are in an area that had been cleared of fire killed trees and planted with Jeffrey pine seedlings. Figure kk (plot 27) represents a burned but otherwise undisturbed low elevation mature Jeffrey pine forest. It is easily observed that there were large fluctuations in the spread and amplitude of autumn temperatures. Soil temperatures continued to decline after the first major snowfall of the winter until January 5- From that date onward, temperatures began to rise but were s t ill below 32° Fahrenheit. Freezing soil temperatures were recorded from December 15 to February 16. From December 23 to January 12, all surface thermistors were 32 degrees or lower. Plot 32, representative of the mature, low elevation pine forests near Galena Creek, would have yielded temperatures very similar to plot 27 except for the fact that it has not been disturbed by fire. No freezing temperatures were recorded at plot 32 during the entire study period. The amplitude and spread of autumn soil temperatures was much less than that observed on plot 27. As with plot 27, soil temperatures declined on plot 32 until early January. Soil frost was observed many times to be restricted to a dark ash layer that covered plot 27. The frost in this ash layer was usually 2 inches thick, the thickness of the ash, and ranged from granular to porous concrete. At times frost was also found in 75 the soil beneath the ash layer. On January 21, free water was found standing over 1 inch of concrete frost that was restricted to the ash layer. Plot 28 is in an open area exposed to the full force of cold westerly winds that blow off the nearby mountains. As a result, there was usually less snow there than on the other plots inside the burn. Winter temperatures were not sign ifican tly different between plots 27 and 28 but fall soil temperatures of plot 28 were higher than plot 27. Between December 15 and January 6 frost exceeded 3.5 inches in depth and ranged from porous concrete to concrete at plot 28. On January 6, the frost was so hard that it was impossible to penetrate more than 6 inches into the frozen soil with a Pulaski. The entire depth of frost was unknown. Also on January 21, water was ponded over k inches of concrete frost but the soil was wet beneath the frost. Average and maximum snow depths were greater on plot 29 than either plot 27 or 28. Temperatures of 32 degrees or lower were recorded only twice during the winter at plot 29. This plot is sheltered from wind and has a more northerly aspect than the other burned and disturbed plots. As a result of the sheltered aspect, fall temperatures were not as variable at plot 29 as at plot 27 and 28. During the winter, a shallow but stable snowpack over plot 29 reduced the occurrence of freezing temperatures. It may be concluded that the burned and disturbed plots with a shallow or non-existent snow cover had greater soil temperature 76 fluctuation during the fall and lower soil temperatures during the winter than nearby undisturbed plots. The frequency of sub freezing temperatures appeared to be reduced by a stable snowpack ) although the ground surface was devoid of litter. Figure ^.--Photograph of plot 27 and diagram of thermistor locations (scale: 1 inch to 4 feet). Figure 46.--Photograph of plot 28 and diagram of thermistor locations (scale: 1 inch to 4 feet). 80 Mount Rose Ski Area A single plot was established at 8^00 feet (Figure ^8) in an open but litte r covered area near the parking lot of the Mount Rose Ski Area. Surrounding vegetation consists of red fir ( A b i e s m agnified), lodgepole pine and Western white pine (Pinus m onticola) . There was a great variation in fall amplitude and spread of soil temperatures. The lowest temperature of the season, 27.5° Fahrenheit, was recorded on November 27 under 3 inches of snow. Soil temperatures rose above 32° Fahrenheit only after a 36 inch deep snowpack had been on the ground for many weeks. After November 27, temperatures slowly rose and became nearly isothermal by February 23 and remained nearly isothermal from February 23 to May 17 when most of the snow had melted from the plot. On December 2, there was 9 inches of very dry porous concrete frost under 23 inches of snow. By January 12, freezing temperatures were encountered only in rotten log material. Road f ill A single plot (Figure *»9) was established on a south facing road f i l l at 6800 feet on the Mount Rose Highway. No freezing temperatures were recorded here although the average snow depth was 3.5 inches with a maximum of 1A inches. 81 Figure 48.--Photograph of plot 38 and diagram of thermistor locations (scale: 1 inch to 4 feet). 82 ,3 2 1► T N PO -E 4 W * Figure bS.— Photograph of plot 35 and diagram of thermistor locations (scale: 1 inch to b feet). 83 Conclus ions of Winter of I967-I 968 According to the U. S. Department of Agriculture ( 1968), the winter of 1967-1968 produced a snowpack that on April 1, 1968 was only jk percent of the 19^8—1962 average in the Lake Tahoe-Truckee River basin. The Little Valley snow course, k miles south of the Slide Mountain temperature plots and at an elevation of 6300 feet, is located in an environment that is very sim ilar to that found near most of the temperature plots. On April 1, 19oS, the water content of the snow course w as'^7 percent of the 19^8-1962 average. The following conclusions are based on information gathered during the winter of 1967~1968: (1) Average 2k inch temperature, as determined by all measurements made from September to late April, decreased approximately 2° Fahrenheit for each 1000 foot rise in elevation. Plots near 6000 feet averaged 39-0° F. , while plots at 7000 and 8^00 feet averaged 37-0° and 3^.3° respectively. (South aspect plots were not included since the fifth thermistor was nearly always placed at a depth of 18 inches.) If the trend continued to be linear, the average 2^t inch soil temperature at elevations over 9500 feet should have been 32° or less from September 1967 to late April 1968. (2) Soil temperatures declined u n ti1 the f ir s t major storm of the winter (November 29) established the winter snowpack. Soil temperatures then usually remained steady or changed only slightly until the snow melted in the spring. Soil frost was generally found when the snowpack was less than 12 to 18 inches deep. When exceptions occurred, the soil had probably frozen prior to snow deposition or when there was only a few inches of snow on the ground. As shown by soil temperature data from plot 27 (Figure 44) , the snowpack insulated the soil from cold a ir temperatures and allowed heat risin g from several feet in the ground to thaw the frozen surface soil. When the snow depths were less than 12 to 18 inches deep, soil temperatures near the surface fluctuated with short-term weather changes. Figure 12, plot 14, is an example of this relationship. The type of vegetation and ground cover had lit t le effect on soi 1 temperatures when snow depth exceeded 12 to 18 inches. The thermistors that were warmest in the fall were nearly always the coolest in the winter. However, 16 of the 114 surface thermistors did not follow this trend. Frost type, depth, and occurrence often changed radically within distances of only a few feet. North aspect forest and brush plots were character ized by: (1) long-term steady soil temperatures 85 beneath a deep snowpack, (2) patchy soil frost at the beginning of winter, and (3) no freezing temperatures after late December. (9) On south aspect forest plots near the ridge tops, freezing temperatures were recorded throughout December, and soil temperatures fluctuated with weather changes throughout the winter. In more sheltered areas, soil temperature fluctuation was very sligh t and no freezing temperatures were recorded where there was a uniform snowpack during the winter. Snow depth on south aspect plots was very shallow near the ridge tops, where wind blew practically all snow to the lee side of the ridge, and relatively deep on sheltered slopes below the ridge tops. (10) On the east aspect, high elevation forest plots froze several times; low elevation forest plots did not freeze during the winter; and forest plots near a windswept ridge top froze more often than the high elevation forest plots. Freezing at east aspect brush plots was less severe than at high elevation east aspect forest plots. Snow depths over east aspect brush covered plots were greater than snow depths recorded over east aspect forest plots. (11) On terraced plots, there was a steep, decreasing 86 soil temperature gradient from the outer edge of the fill slope to the inner cut slope, during snow free periods. This gradient was reversed during periods with a snow cover, but the gradient was very slight. Snow depth increased from the outer to inner edge of the terraces and soil freezing occurred most often at the outer edge of a terrace. (12) The burned and disturbed plots with a shallow or non-existent snow cover had greater soil temperature fluctuation during the fall and lower soil tempera tures during the winter than nearby undisturbed plots. Soil frost was usually restricted to an ash layer that covered plot 2 7 . (13) The deepest confirmed frost depth (9 inches) was recorded at plot 38. Porous concrete frost greater than 6 inches deep was found in the Galena Creek burn. (14) Soil temperatures of 32° F or less were observed from November 27 to March 22. During the period of greatest frost occurrence, November 27 to February 2, freezing temperatures were recorded each week at 9 to 15 of the 38 plots. No more than 15 of the 38 plots were frozen at any one time. Probably 50 percent of the area from 6000 to 7000 feet in the area of the temperature plots was unfrozen throughout the entire winter. The frost depth and type changed rapidly 87 within a few feet but, except for the Galena Creek burn, the frost was porous and would not have hindered infiltration. Since at least 50 percent of the area at any given time was un frozen, soil frost, as found under 1967- 1968 conditions, would not have been a significant contributor to flooding if a warm rain had melted the snowpack at any time during the winter. SOIL FROST RECONNAISSANCE (1968-1969) Descri pt Ion of 1968-1969 Study Areas The soil temperature study was discontinued during the winter of I968-I 969 in favor of a general reconnaissance of soil freezing conditions on granitic soils in the Sierras from Bridgeport to Susanville. Research was usually restricted to areas that were readily accessible from all-weather highways (Figure 2). Studies were made on all aspects, on slopes from 0 to 70 percent, on a wide variety of vegetative communities, and between 4300 and 10,100 feet in elevation. Appendix 3 contains maps of each of the study areas. Table 4. Areas studied during the winter of 1968-1969 Area Vegetation— Aspect elevation (feet) Canyondam 3 S 4300 Copperva1e 3 N, W 5250-5650 Susanv i i1e Summ i t 1 S 4800 Deans Ridge 3 E 5400 Milford Grade 1, 3 N, s, E 4800-6050 Constanti a 1 N, s, E 4600 Yuba Pass 2, 3, 5 s, w, N 5400-6650 Dog Valley 2 N, S, E 6100-6500 Slide Mounta i n 2, 6, 10, 11, 12 N, S, E, W 7000-10,100 Sand Harbor 3 W 6350 Spooner Summit 1 , 2 N, S, E 5200-7100 Luther Pass 6 N 7800 Cloudburst Canyon 1 N 6300 Bootleg Canyon 1 E 6400 Pimentel Meadow 2 N, S, E 7500 ]_/ See section on vegetation classification for winter of I 9&8-I 969 study areas, page 89. 89 Vegetation Classification TT968-1969) ' Community classification based on the occurrence of plants of small stature could not be used during the winter of 1368-1969 since many areas were visited for the fir s t time only after snow had covered the ground. Forest communities were classifie d according to the relative abundance of forest trees occupying the site. A total of 9 vegetative communities were sampled during the winter of 1968- 1969. They were: (1) Jeffrey pine-bitterbrush. Communities with an overstory of Jeffrey pine and an understory of bitterbrush {Purshia tridentata ). (2) Jeffrey pine-white fir. Communities dominated by Jeffrey pine and white fir. Sugar pine {Finns iambertiana) , incense-cedar {Libocedrus decurrens), red fir, and lodgepole pine are occasionally encountered as individual trees. (3) Mixed conifer forest. Forest stands composed of a mixture of ponderosa pine, white fir, incense-cedar, sugar pine, and Douglas-fir {Pseudotsuga nenziesii) . In some cases, Jeffrey pine may replace or be associated with ponderosa pine. This community may be further broken into the wet, west side mixed conifer forest and a drier, east side mixed conifer forest. (A) White fir. Stands composed of white fir with red f ir en tirely lacking or occurring as scattered individuals or small groups. The canopy is closed and an understory is usually lacking. (5) Red fir. Stands dominated by red f ir with white fir entirely lacking or occurring as scattered individuals or small groups. The canopy is closed and an understory is usually lacking. (6) Lodgepole pine. Forest stands dominated by lodgepole pine. Red f ir and Western white pine may occur as scattered individuals. (7) Mountain hemlock. Forest stands composed of mountain hemlock (Tsuga mertensiana) , Western white pine, lodgepole pine and red fir. (8) Aspen. Forest stands composed of quaking aspen (Populus tremuloides ). (9) Lodgepole pine-whitebark pine. Forest stands composed of scattered individuals and small groups of lodge pole pine and whitebark pine {Finns alhicaulis ). The Jeffrey pine-bitterbrush community is found at lower eleva tions and on drier sites than the Jeffrey pine-white fir community. Both communities are found typically on the east side of the crest of the Sierras. The mixed conifer forest is best developed on the west slope of the Sierras but it is also found on moist east side sites. The white fir community is usually found within the same elevation range and environment as the mixed conifer forest. The red f ir and lodgepole pine communities are both found at higher elevations and 91 cooler sites than either the white fir community or mixed conifer fo re st. Mountain hemlock is found on cool, high, moist north slopes ) and the lodgepole pine-whitebark pine community is found on dry, warm sites at high elevations just above the red fir and lodgepole pine communities. Aspen may be found in cool moist canyon bottoms or around springs within any of the above communities with the possible exception of Jeffrey pine-bitterbrush and the mixed coni fer forest at low elevations. 92 P rocedure for Winter of 1968- I 969 Dest ruct i ve transects The most reliable way to determine if the soil was frozen beneath a snowpack was to dig a hole through the snow down to the soil surface. This practice had one major fault, namely that it was impossible to return to exactly the same spot at a later date and again record the presence or absence of frost, since the initial v is it had destroyed the original environment. Areas were studied by running destructive transects which consisted of from 5 to 20 or more points spaced at one chain inter vals along a straight line. At each point a hole was dug through the snow to the soil surface. At each point, aspect, percent slope, elevation, snow depth, litte r depth, and vegetative community were recorded regardless of the presence or absence of frost. If no frost was encountered, this was also recorded. Likewise if frost was encountered, the type and thickness were recorded. It was felt that at least 5 points were necessary to character ize a given elevation, aspect and vegetative community. Transects had two d istin ct purposes: (1) they were used to characterize one community as in 5 to 10 point transects, or (2) they extended from one community to another or through a number of aspects or more rarely, extended from one elevation zone to another. The majority of transects consisted of 10 points and fell within one vegetative commun i ty . 93 beneath the snowpack. This practice was never entirely successful since compacted snow covered the tube opening thus preventing soil from entering the tube. A modification of the Mount Rose Snow Sampler, with its sharp cutting edge, may be more successful than a conduit. Any method of probing the soil beneath the snow should have the capacity to bring a sample of frozen ground to the surface in order to determine its type and thickness. Fros t moi sture content The moisture content by weight of frozen soil samples was determined by weighing soil samples before and after drying, sub tracting the wet weight from the dry weight and dividing the differ ence by the dry weight. Occurrence of hydrophobic soils The relationship of hydrophobic soils to soil freezing was tested by placing a drop of water on the frozen soil and on the soil just beneath the frozen layer. The soil was considered hydro- phobic if the water beaded up on the surface and did not readily penetrate the soil. Inf i 11 rat i on studies A rough estimate of the infiltration capacity of frozen soil was determined by placing a 3-3 inch diameter metal ring on top of an undisturbed layer of frozen soil and sealing the space between the soil and ring with a bentonite paste. Seventy milliliters of water (approximately 0.5 inch depth) were then discharged into the ring and any water remaining in the ring after 15 minutes was removed from the ring and measured. A control was run on unfrozen soil if it was available. After the test was completed, the frozen layer was removed to determine its thickness and frost type i At times some water seeped between the bentonite and soil surface. 95 Resu1ts and Discussion of Winter of 1968-1969 Soil freezing conditions may be divided into three broad but easily identifiable time periods: (1) fall to first major winter storm, (2) f ir s t major winter storm to mid-March, and (3) mid-March to the spring snow thaw. Period One (increasing frost occurrence) was characterized by steadily declining maximum and minimum temperatures, mild rain or snowstorms and the establishment and gradual increase in the area covered by a shallow veneer of snow. Period One began in late September with tne first occurrence of soil frost. During this time, frozen soil was nearly always found under the snow. In early December, the shallow snowpack and its associated frost had reached a maximum areal distribution. Period Two (decreasing frost occurrence) was characterized by typical winter storms of long duration with heavy snowfall and deep snowpacks. Soil frost was widespread at the beginning of the period but practically non-existent at the end of the period. During Period Two, soil between 5000 and 7000 feet thawed sooner than soil above or below this range. Period Three (spring snowmelt) was characterized by rising temperatures, milder and less frequent storms and a declining snow- pack due to melting. During this time, soil frost was found only around the margins of snowbanks. Data w ill be presented with four major intentions: (1) to substantiate the three period concept, (2) to show the trends in frost occurrence at several sites throughout the winter (the Deans 96 Ridge, Constantia, Slide Mountain, and Pimentel Meadows study sites were visited several times during the winter), (3) to show the effect of frost on the infiltration capacity of soil and, {b) to show the effect of water-repellency on soil frost. Appendix b contains the raw data collected from transects that were run during the previous winter. These transects, plus obser vations made at other times, comprise the basic information used to make inferences concerning frost occurrence in the Sierras during the previous winter. Appendix 3 contains maps of each of the areas studied during the winter of 1968-1969. The location and date of running of each transect is shown in Table 5- Several other days were spent in the field during which time no transects were run. Table 6 is a summary of frost occurrence by month. The trench in frost occurrence are based on all of the transects run during the v/inter. Since Table 6 was based only on the data collected from transects, it cannot be considered as a true representation of monthly frost conditions on the east side of the northern Sierras. The 1968-1969 snowpack in the Sierras exceeded most previous records. According to the U. S. Department of Agriculture (1969). the snowpack in the Sierras on April 1, 1969 varied from 215 percent of normal in the Truckee River drainage to 267 percent on the head waters of the Walker River drainage. Frequent, violent storms and deep, powdery snow hindered field work from January to mid-March. Table 5. — Date and location of each transect run during the winter of I968-I 969 Period One Period Two : Period Three : Sept. Oct. Nov. Dec. Dec.: Jan. Feb. Mar. : Mar. April May : Area da te Cariyondam : 25 Coppervale : 25 Susanv i 11e Summi t : 25 Deans Ridge 27 9 Mi 1 ford 23 : 3 Constant i a 23 13 : k 6 : Yuba Pass 31 : Slide Mounta i n 21 16 1 k : 18 27 1 : 22 15 22 Sand Harbor 15 Spooner 16 : k Bootleg Canyon : 28 A : Pimentel Meadows 29 : 28 k : 98 Table 6 .--Summary of frost trends at all sites for winter I 968-I 969 percent of all observations * 1- 4 -J (/) O L- L i_ Frozen 1 i tter Frozen i 1 Porous Concrete Stalactte i Granular Month Concrete Thawed Period One September — — W — — — October — — 37.9 6.9 20.7 34.5 November — 10.8 26.5 4.9 27-4 30.4 December — 24.3 16.2 5-A 40.5 13.5 Period Two December — 10.0 23. 4 — 40.0 26.6 January — 8.8 6.1 — 10.2 74.9 Februa ry — 22.5 5.0 — 15.0 57.5 March 23.9 26.1 50.0 Period Three March Ij ft ||j|J| Apri 1 , | ,! || j;| J |'|iii <1 May __ _ . ]_/ only frost type observed 39 Three period concept Period One (i ncreas inq frost occurrence) Soil frost was f ir s t noted in the fall of 1968 on September 21, at 7000 feet, in the area of Slide Mountain. On September 19 there was a mild snowstorm. Two days later, granular soil frost was found in the surface layer of soil that had become wet from melting snow. Frost was found only in soil without a litter cover and only under or close to snow. Frost ranged from 0.5 to 1.5 inches thick and usually consisted of small ice crystals on the underside of soil particles. On October 15, freezing conditions sim ilar to those found at Slide Mountain on September 21, were found on a north facing siope on the west side of Spooner Summit at an elevation of 7100 feet. Granular frost from 0.5 to 3 inches thick was found in bare (no litter) soil under and within a few inches of a shallow patch of snow. The ice crystals were too small to see with the unaided eye. Also on October 16, at 7600 feet, stalactite frost from 0.5 to 1 inch thick was observed for the fir s t time on the east and west sides of the Carson Range. In November, snow did not melt a few days after a storm as it did in September and October. As a result, by November 15, the snow and frost level had lowered to approximately 7000 feet on the east side and 6300 feet on the west side of the Carson Range. Frost pro bably occupied much of the area above these elevations. On transects SHT-1 (November 15), SLT-5 (November 15) and SLT-6 (November 15), frost ranged from 1.5 to 2 inches thick and consisted of approximately 100 25 percent granular and 75 percent frozen litter frost types. In late November, temperatures and the snow level became low enough to cause soil freezing below 7000 feet. An area two and one half miles north of Constantia in Long Valley, California and the Milford Grade were examined on November 23. No snow or frost was found on north, south and east slopes at ^600 feet in Jeffrey pine-white f ir and Jeffrey pine-bitterbrush communities at the Constantia site. In the Milford area, no frost or snow was found between AA00 and 6050 feet. The vegetation consists of old growth and selectively logged east side mixed conifer forest. On November 27,Deans Ridge (5^00 feet), the most northerly study area, was visited for the first time. Vegetation growing on the ridge consists of east side mixed conifer forest that appears to be drier than the Milford site. The three previously named sites are v/ithin the transition zone between the mixed conifer forest and the sagebrush dominated vegetation of the Great Basin. Seventy-five percent of the points studied at Deans Ridge were frozen with up to 1.5 inches of stalactite, granular and frozen litter frost types. The most evident difference between Deans Ridge and the Milford-Long Valley area was one of snow cover. A very thin snow mantle at Deans Ridge allowed the decrease in soil temperatures that resulted in soil frost formation. Pimentel Meadows, 8 miles north of Bridgeport, was the site of the thickest layer of frost encountered during Period One. A total of 8 inches of porous concrete and granular frost was found in a coarse textured soil on a 60 percent slope with a N50E aspect on November 29. The frost occurred in a small patch of mountain 101 mahogany (Ceraocarpus ledifolius ) surrounded by old growth Jeffrey pine and white fir. On December soil frost was found at 6900 feet on south slopes at Slide Mountain (transect SLT-8, December A). Freezing was not very severe and occurred mainly in shaded areas. On the north side of the same ridge, (transect SLT-9), soil frost was deeper, more uniform and covered a greater area than the south slope. Stalactite frost was recorded for the last time in Period One on this date (transect SLT-8). Transect SLT-10 (December k) showed that at 9000 feet most of the area was occupied by porous concrete frost that ranged from 1 to ^4.5 inches thick. This transect also indicated that the snow was becoming deep enough to allow thawing of the frozen soil. December k was the last day spent in the field under Period One conditions. A series of heavy snow storms starting on Decem ber 10, increased the depth of the snowpack to a point where Period Two conditions were initiated. It may be concluded from Period One that: (1) granular frost is the first recognized frost type, (2) granular, stalactite and frozen litte r frost types dominate the period, (3) stalactite frost is not observed until the soil has become moist from fall rains, (^) snow depths throughout the period usually do not exceed 12 inches, (5) porous concrete frost may form very early in the season, but it is restricted to elevations above 7500 feet, (6) the frequency of frost increases as aspect changes from south through east to north. I 02 Peri od Two (decreas ing frost occurrence) The fir s t major storm of the winter occurred in early December and caused a major change in frost distribution. Soil frost had reached its maximum areal extent by early December, but rather than remain stable, the frost thawed rapidly under the exception ally deep snowpack that quickly built up during December and January. On December 31, only 1 of 8 test points were frozen in the area of Yuba Pass. Snow depths ranged from 18 to 50 inches. On January 3, at Milford, 2 out of 31 sample points were frozen between 4800 and 6000 feet. Snow depth ranged from 7 to 22 inches. Below 4800 feet, porous concrete frost from 1 to 1.5 inches thick, was found along the edges of snowbanks. The effect of aspect and snow depth was noted in the area of Spooner Grade on January 4 (Figure 50). At 5200 feet, on West and N70W slopes, frost was found in bare spots (no litter) and along the edges of snowbanks. The opposite side of the canyon, with an aspect of S70E, was entirely free of frost. Snow depths on both sides of the canyon ranged from 4 to 12 inches. Vegetation on both sides of the canyon consists of small patches of Jeffrey pine growing within a bitterbrush-big sage community. Also on January 4, at 6640 feet near Spooner Summit, northeast, east and southeast slopes were unfrozen under a snow cover that ranged from 7 to 24 inches deep. Vegetation consists of the east side mixed conifer forest and the Jeffrey pine-white fir community. Near the summit of the Spooner Grade, no frost was found in a southeast facing Jeffrey pine-bitterbrush community at 7120 feet 103 where snow ranged from 13 to 25 inches deep. Figure 50.--View looking north from Interstate Highway 50 near the bottom of the Spooner Grade at 5200 feet. On January 4, t;he left side of the gully (aspect S70E) was unfrozen while the right side of the gully (aspect N70W) was frozen. However, nearby, all sample points were frozen in a north aspect Jeffery pine-white fir-red fir community at 7100 feet on the west side of Spooner Summit. The snowpack ranged from 14 to 24 inches deep and showed indications of being drifted by wind. The same area was frozen on October 16 and appears to be a fairly cool spot. Frost ranged from 0.5 to 2 inches thick and consisted of 70 percent granular frost and 30 percent frozen litter. Two sample points were within an area that had been burned in the fall of 1967. At these points, the frost was restricted to the 1 ok black as layer on top of the ground. This phenomenon was recorded in the Galena Creek burn during the winter of 1967”1968. On the basis of findings at Milford, Yuba Pass and Spooner Grade, it appears that by the middle of January, there was very little frost from 5000 to 7000 feet on south, east and west slopes. No definite statement concerning north slopes can be made because very few north slopes were sampled. Frost was found near 5000 feet on west and northeast slopes at Milford, north, south and east slopes at Constantia and west and northwest slopes at Spooner. South slopes at 5000 feet were usually unfrozen. The low elevation frozen areas at the eastern limit of the east side coniferous forests characteristically have a shallow snowpack that rapidly advances and recedes with changes in the weather. Figure 51 is typical of the forests near the eastern limit of conifers in the Sierras. 105 Figure 51-““South aspect Jeffrey pine-bitterbrush forest at the Constantia study site. The vegetation of the unfrozen areas from 5000 to 7000 feet is dominated by the mixed conifer forest (Figure 52) and the Jeffrey pine-white fir community. Deep snowpacks are characteristic of this elevation range. Elevations above 7000 to 7500 feet appeared to be still frozen in mid-January. Later observations tended to substantiate a general pattern of a thawed band from 5000 to 7000 feet between two frozen bands. Observations made near the end of Period Two indicated that areas above 7000 feet had nearly thawed, but portions of the eastern limits of the Sierra 106 coniferous forests remained frozen. Figure 52.--Mature mixed conifer forest at 6650 feet near the summit of Yuba Pass. Canyondam, Coppervale Ranger Station, and Susanville Summit are near the northern limit of granitic soils in the Sierras. On January 25, no frost was found at these sites where the snow was greater than 6 inches deep. The Canyondam and Coppervale sites are dominated by the west side mixed conifer forest, while the Susanville Summit site is dominated by Jeffrey pine-bitterbrush. 107 Bootleg Canyon fa lls within the transition zone between the Sierra Nevada conifer forests and the sagebrush communities of the Great Basin. This area, like all of the other areas in the transi tion zone, was frozen when it was visited on January 28. At the lower end of Bootleg Canyon, under 10 to 16 inches of snow at an elevation of 6400 feet, soil frost was found at 90 percent of the points sampled. The frost was found on a 10 percent slope with a N70E aspect on a river terrace above the West Walker River. Vege tation consists of dense sapling and pole sized Jeffrey pine with some isolated single leaf pinyon trees. Areas with no litter were frozen with 2 inches of porous concrete frost while the upper 1 or 2 inches of litter were frozen in litter covered areas. The greatest depth of frost was 3 inches and consisted of 1 inch of frozen litter over 2 inches of porous concrete frost. Exceptionally deep snow hindered field work after late January. However, limited observations made at Deans Ridge, Dog Valley and Luther Pass, California and Slide Mountain indicated that the soil in these areas had thawed. At Dog Valley on January 31, no frost was found on a 20 per cent slope with 25 to 40 inches of snow at 6100 feet and a N20E aspect. Vegetation in the area consists of Jeffrey pine, white fir and incense-cedar. East and south slopes with 45 to 65 inches of snow at 6500 feet were unfrozen. At Luther Pass on February 1, no frost was found under 124 inches of snow in a red f ir stand on a 40 percent northeast facing slope at 7800 feet in elevation. However, 2.5 miles west of 108 Woodfords, 1 to 3 inches of concrete and porous concrete frost was found on a flat with a N10W aspect near the West Fork of the Carson River at an elevation of 6300 feet. Vegetation consists of white fir, Jeffrey pine and mountain mahogany. Frost was found where the snow was less than 30 to 35 inches deep. The frost probably developed under a shallower snowpack since much of the snow in the area was less than 1 week old. By mid-March it appeared that Period Two had ended. It may be concluded from Period Two that: (1) stalactite frost did not occur during this period, (2) the occurrence of granular frost decreased and the occurrence of porous concrete frost increased during this period, (3) low elevation plots with a shallow or fluctuating snow- pack remained frozen throughout the period but conclusions 2 and 3 were still valid for these areas, (4) the depth of all frost types decreased with time, (5) most areas were frozen under a shallow snowpack at the beginning of the period, but these areas quickly thawed when a deep snowpack was established, (6) soil frost thawed most rapidly between the elevations of 5000 to 7000 feet on the east slope of the Sierras (the Sierra Nevada mixed conifer forest is generally confined to these elevation zones), (7) elevations below 5000 feet on the east slope remained frozen throughout the period, (8) sites above 7000 feet thawed less rapidly than elevations below 7000 feet but were generally thawed by the end of the period, (9) at least 12 inches of snow was needed to allow thawing of soil frost and to prevent further freezing, and (10) as elevation increased more time and a greater snow depth was needed to allow thawing. Period Three (spring snow melt) After mid-March, lit t le frost was found beneath the snow. Granular frost was found around the edges of melting snowbanks. Beneath the snow, frost extended 6 to 12 inches under the edge of the bank and reached the soil surface. Frost extended for several inches away from the bank but in these cases, the frost was beneath the soil surface since the exposed surface was easily thawed by the sun. Figure 53 shows examples of the different patterns that melt ing snowbanks assume in the spring. Figure 53•--Snowbank patterns in a large brushfield 1 mile south of the Christmas Tree on Slide Mountain. Late April or early May 1968. n o Peri od i c study areas Four study sites were visited periodically during the winter in order to sample the changes that soil frost goes through at a specific site during a winter. The study sites were Deans Ridge, Constantia, Slide Mountain and Pimentel Meadows. Observat i ons over 7500 feet near Slide Mounta i n Slide Mountain was the only area where it was easy to make observations over 7500 feet in elevation. These high elevation observations will be reported separately to preserve their con- tinui ty . The firs t frost was noted in an area over 7500 feet on September 21. By mid-October, the effect of topography on frost occurrence was quite evident. On October 16, three transects were run between the Mount Rose Ski Area and Tahoe Meadows near the Mount Rose Highway. Two transects, SLT-1 (October 16) at 8750 feet, and SLT-3 (October 16) at 8500 feet, were run within the lodgepole pine vegetative type, while SLT-2 (October 16) at 9000 feet was run entirely within the mountain hemlock vegetative type. SLT-1 was run on a flat ridge top slig h tly above Tahoe Meadows and entirely within a stand of scattered lodgepole pine trees. There was some grass on the transect but no brush. Transect SLT-2 ran diagonally across a spur ridge that connects Slide Mountain with the main ridge of the Carson Range. The trees within the transect are scattered singly or in small groups and consist of 11 ] mountain hemlock, lodgepole pine and Western white pine. Transect SLT-3 was run in a dense stand of lodgepole pine with mountain hemlock, red fir, and Western white pine occurring as scattered individuals. There is no brush on the transect and the litte r layer is well developed and covers most of the ground. Both lodgepole pine stands are on shallow valley bottom sites on either side of the ridge top mountain hemlock forest where transect SLT-2 was run. Soil along transect SLT-1 was dominated by granular frost that ranged from 0.5 to 1.5 inches thick while soil near SLT-3 was dominated by frozen litte r that ranged from 0.5 to 1 inch thick. Approximately 80 percent of the area around both transects was frozen. Snow over both plots ranged from 0 to 6 inches deep. Soil near transect SLT-2, while topographically higher than the other transects, had only 20 percent of the sample points frozen. The height and spacing of the trees and the distribution of the litter was similar to SLT-1. A possible explanation for the particular distribution of frozen ground may be attributed to cold air drainage. Cold air draining at night from the moderately steep ridge tops of the Carson Range collects in the relatively shallow valleys occupied by Tahoe Meadows and the upper reaches of Browns Creek. Because of this, the night time temperatures are lower in the valleys than on the ridges, causing freezing in the valleys but not on the higher and steeper slopes. A few weeks later, the above situation changed slig h tly. On transect SLT-A (November 1) freezing was quite extensive on steep ] 12 north slopes but almost entirely absent on south and gentle north slopes. The transect was near the south end of Tahoe Meadows and ranged in elevation from 8600 to 8960 feet. Freezing conformed to snow distribution and the distribution of mountain hemlock. The mountain hemlock forest and the frost were restricted to a steep, north slope. Approximately 95 percent of the slope was frozen with 0.5 to k inches of frozen litter, granular and porous concrete frost. Granular frost and frozen litte r was found where there was a continuous litter layer while porous concrete frost was found where litte r was absent. No frost was present at the top of the ridge, where the vegetation changed abruptly from mountain hemlock to Western white pine. Only 1 out of 6 spots were frozen in the lodgepole pine stand at the foot of the steep, frozen slope. Western u / h ;. Lodgepol e Pin e Unfrozen Figure 5^.--Profile of transect SLT-A (November 1). 113 A second transect, SLT-3 (January 18), was run in a mountain hemlock forest at 8200 feet 1 mile east of the Mount Rose Ski Area (Figure 55). The transect was on a **0 to 70 percent northeast facing slope that was entirely frozen with porous concrete frost that ranged from 1 to 2 inches thick. Snow depth ranged from 51 to 67 inches. A sample of porous concrete frost taken from the area had a moisture content of 5^.1 percent by weight. This transect followed the same trends as other transects run in mountain hemlock forests. It appeared that soil under mountain hemlock forests on north aspects had been frozen since the beginning of November or perhaps even earlier. Later work indicated that areas occupied by mountain hemlock forests had probably thawed by late February. Figure 55.“"Site of transect SLT-13 (January 18). 11 ^ On November 22, transect SLT-7 was run from the Nevada High way Department Maintenance Station on the Mount Rose Highway at 7^00 feet up Galena Creek for approximately 1 mile and then to the northwest up the east face of Mount Rose to approximately 8600 feet. The transect passed through a mixed red fir, lodgepole pine, Jeffrey pine forest with inclusions of snowbrush on the south side of Galena Creek, across an aspen grove near the creek, through a Jeffrey pine forest on the north side of Galena Creek and then through a big sage-snowbrush community on the east face of Mount Rose. About 60 percent of the north facing slope above the aspen grove was frozen with stalactite, granular, porous concrete and frozen litte r frost types. The snow cover was patchy and averaged about one inch in depth. Small patches of closed forest with a deep litter layer were unfrozen. The aspen grove occupied a broad flat adjacent to Galena Creek. The grove was divided by a small gully into two aspects. One side of the gully faced north and about 95 percent of the area was frozen with 1 inch of granular frost. The other side of the gully faced S70E, but unlike the north facing grove, only about 10 per cent of the grove was frozen. A south facing extension of the aspen grove on the north side of Galena Creek was partially frozen. Soil freezing and snow were practically non-existent on south and east facing slopes except for isolated flats and depressions that favored the accumulation of snow. At the maximum elevation of the transect, an east facing slope at 8600 feet, there was no 115 indication of soil freezing except near the edges of snowbanks. On January 18, transect SLT-11 (January 18) was run on a south facing slope at 7500 feet. Soil frost was found where wind had blown the snow away from ridge tops, exposed saddles, and from around trees. One area where the wind had removed the snow from a saddle was frozen with 1 inch of granular frost that had a moisture content of 15.8 percent by weight. Below the granular frost was 4 inches of porous concrete frost with a moisture content of 24.6 percent. On slopes less than 25 percent, the snow ranged from 0 to 25 inches deep. On 25 to 60 percent slopes, the snow ranged from 0 to 14 inches deep. Frost was found where the snow was less than 12 inches deep. On the opposite side of Galena Creek from transect SLT-11, no frost was found on northeast and northwest slopes along transect SLT-12 (January 18). Snow depth ranged from 19 to 40 inches. Vege tation on the north side of the canyon was dominated by Jeffrey pine with single white fir trees scattered among the pine. The north facing slopes were dominated by white and red fir with Jeffrey pine being subordinate. Transects SLT-11 and SLT-12 were run about 300 yards east of the beginning of transect SLT-7 (November 22). Reconnaissance of the Slide Mountain area on February 27 and March 1 revealed that soil frost could be found only on bare wind swept ridge tops or saddles (Figure 56). No frost was found under 156 or 186 inches of snow on a 30 to 60 percent north slope at 8200 feet in elevation. Vegetation consisted of sapling and pole sized red fir, Western white pine and an occasional mountain hemlock 116 tree. Nine points were sampled and two holes were dug in the snow down to the soil. No frost was found at 9000 feet on a southeast slope under 156 inches of snow. Vegetation consisted of scattered lodgepole pine and whitebark pine. At the west end of Tahoe Meadows where the snow was 204 inches deep, the ground appeared to have thawed. Near Incline Village, no frost was found in the soil beneath 90 to 108 inches of snow in a dense stand of white fir and Jeffrey pine poles at 6700 feet on a S60E aspect. Figure 56.— Windswept ridge top at 8600 feet on Slide Mountain. Note the bare spots, thin snow cover and sparse vegetat ion. Observations over 9000 feet were prevented for most of the winter decause of deep, powdery snow that hindered movement by foot and mechanical means. On March 15, it was possible to reach 117 an elevation of 10,100 feet about 1.5 miles southwest of Mount Rose. Probing of the soil with an aluminum conduit beneath 150 inches of snow in a south facing whitebark pine forest (Figure 57) indicated that the soil was probably thawed at that elevation. The soil beneath an east facing whitebark pine-lodgepole pine forest at 9300 feet appeared to be also thawed. Figure 57.__Whitebark pine forest on a south slope at 10,100 feet in the Carson Range of Nevada. Mt. Rose (10,778 feet) is in the background. March 15, 1969* 118 Frost trends at Deans Ridge Deans Ridge is approximately 2 miles southeast of Eagle Lake and is in the transition zone between the Sierras and the Cascade Range. The ridge runs approximately southeast and is the most northerly area of granitic soil in the Sierra Nevada known to the author. Vegetation consists of the east side mixed conifer forest. Approximately 10 years ago, the area was disturbed by a heavy selection logging treatment (Figure 58). The area was visited November 27 just before the firs t major storm of the winter, February 9, in mid-winter and on April 15. Figure 58.--Deans Ridge study site. 119 On November 27, 2 transects were run on the east side of Deans Ridge at an elevation of approximately 5^00 feet. Vegetation around both transects was nearly identical and snow depth ranged from 0 to 2 inches on both transects. Soil frost was found at 12 of 13 (92.3 percent) sample sites on a 40 to 60 percent northeast slope (DRT-1, November 27). Approximately 600 feet away, 6 of 11 sample points (5^.6 percent) were frozen on a nearly level south east slope (DRT-2 November 27). The same area was visited again approximately 9 weeks later on February 9, 19&9- On that day snow depths ranged from 15 to 33 inches. No soil frost was found where snow depth exceeded k to 6 inches in depth. The only frost encountered was 2.5 inches of porous concrete frost under 1 inch of thawed soil surrounding the bole of a tree where the snow had melted. Table 7- Frost trends at Deans Ridge (1968-19&9) Date November 27 February 9 slope slope : flat flat (percent average : (percent average area depth : area depth frozen) ( in.) : frozen) (in.) frozen 1i tter 30.8 0.5 : 18.2 1.5 granu1 a r 38. A 0.8 : 27.3 1.5 porous concrete — ------. — — no frost concre te — ------: — — stalacti te 23.1 1.1 : 9- 1 1.5 unfrozen 7-7 A5.** 120 Frost trends at Constantia The Constantia site is in a sheltered canyon at 4600 feet near the floor of Long Valley. The Jeffrey pine-white fir community is found on east and north slopes while the Jeffrey pine-bitterbrush community is found on south slopes. The area occupied by the forest was covered with a thin veneer of snow for most of the winter. Figures 59, 60 and 61 show the forest vegetation in the areas where transects were run. Figure 59.""North and east aspect Jeffrey pine-white fir poles and sawtimber. 121 Figure 60.--Dense stand of Jeffrey pine and white fir saplings and poles on a north slope. Figure 61.— Open, south aspect Jeffrey pine-bitterbrush commun i t y . 122 Table 8 . Frost trends at Constantia (1968-196 9) Aspect north and east south a 1 1 sampled s i tes average percent average percent average percent fro st- depth area depth area depth area type (in.) frozen (in.) frozen (in.) frozen November 23, 1968 no s o i1 frost December 13, 1968 1 2 ______1.7 30.0 1.7 13.6 3 1 .1 33-3 0.8 30.0 1.0 31 .8 4 5 1 .3 58.3 1.1 40.0 1 .2 50.0 6 2/ 8.*4 4.5 average snow depth 0.6 i nches February 4, 1969 • 1 2 2.2 41.7 2.1 80.0 2.1 52.9 3 2.3 16.6 — — 2.3 11.8 4 5 1.8 41.7 2.0 20.0 2.0 35.3 6 average snow depth 2.8 i nches March 8, 1969 1 2 1 .3 40.0 0.7 50.0 1 .0 43.8 3 4 5 1 .4 60.0 0.7 33.3 1 .2 50.0 6 16.7 6.2 average snow depth 2.2 i nches April 9, 1969 no soil fros t 1/ refer back to structural forms of frost (page 5) 2/ not frozen ]23 On November 23, no frost was found in the study area. However, by December 13 (Table 8) conditions had changed quite drastically. Comparison of results from transects run on December 13 (CTT-1 , CTT-2 and CTT-3) and February k (CTT-^ and CTT-5), indicate that snow depth had increased, there was less granular frost and frozen litter, more porous concrete frost and greater frost depths. Frost depth of all frost types ranged from 0 to 2.5 inches thick on December 13, while on February 4, frost depth ranged from 1 to 5 inches thick on all aspects. On March 6, frost conditions had changed a second time. On this date, no granular frost was recorded, average frost and snow depths had decreased since February k, and there was a very definite distinction between frost conditions on north and south slopes. On all slopes frost depth ranged from 0 to 2.5 inches thick. March 6 was the fir s t time that frost conditions on north and south slopes were significantly different. Frost depth on south slopes was approximately half that on north and east slopes. A portion of the south slopes were entirely thawed. More porous concrete frost was recorded on south slopes than on east or north slopes but litte r is thin and patchy on south slopes, so this condition should be expected. Exploration of the forest to the west of the areas where transects have been run showed on March 6 that snow depth increased with increas ing elevation and frost depth and occurrence decreased with increased elevation and snow depth. No frost was found on north slopes at ^800 feet where the snow depth was greater than 12 to 1A inches. There Mb appears to have been a band of frozen soil about 0.5 mile wide at the eastern edge of the conifer forest. This band was probably present for most of the winter since snow depth at elevations greater than A800 feet were probably always greater than 12 inches. 125 Frost trends at Pimentel Meadows Pimentel Meadows, the most southerly study site, is approximately 8 miles northwest of Bridgeport, California. Vegetation in the area where the transects were run consists of an unlogged stand of Jeffrey pine and white fir at an elevation of 7500 feet. North, south and east slopes ranging from 10 to 60 percent were sampled on November 23, January 28, March 4 and April 17. Figure 62 shows the area where transects were run during the winter of I968-I 969. Figure 62.--Pimentel Meadows study site. On November 29, transect PMT-1 indicated that at 7500 feet, the soil had thawed or was in the process of thawing on south slopes while east and north slopes were very definitely frozen. Frost depth ranged from 1 to 8 inches thick and was dominated by granular frost. Snow depth ranged from 0 to 2 inches deep. 126 On January 28, porous concrete frost from 1 to 2 inches thick was found on north and some northeast slopes at an elevation of 7500 feet and with an average slope of 60 percent. The occurrence of soil frost decreased on northeast to east slopes and completely disappeared on south slopes. Snow depth on all aspects ranged from ^0 to 66 inches. Comparison of data from transects PMT-1 (November 29) and PMT-2 (January 28) indicates that between November 29 and January 28, the south slopes entirely thawed, dominant frost type changed from granular to porous concrete, average frost thickness decreased and snow depth increased. On November 29, the granular frost ranged from 1.5 to 5 inches thick with an average depth of 2.8 inches. By January 28, the dominant frost, porous concrete, ranged from 1.5 to 2 inches thick and had an average depth of 1.7 inches. Observations on March k showed that snow depth had increased since January 28 and that practically all frost had thawed. The only frost encountered on transect PMT-3 (March k) was 1 inch of porous concrete frost on a N10W slope under 72 inches of snow. Average snow depth on all aspects on November 29 was 1.2 inches, on January 28, 52.8 inches, on March 4, 72.k inches and on April 17, ^0 inches. Except for the November 29 and April 17 observations, there was no difference in snow depths oh north, east and south slopes. 127 Table 9- Summary of frost trends at Pimentel Meadows (winter of 1968-1969) November 29 January 28 Ma rch k ave rage percent average percent average percent frost depth area depth area depth area type (in .) frozen ( in .) frozen (in.) frozen 1 2 3.0 6.7 1.7 Al.7 1.0 9. 1 3 2.8 53-3 — — — — k — — — — ~ — ______5 3-0 6.7 6 — - 33-3 58.3 90.8 128 The effect of soi1 fros t on infiltration Tests on the infiltration capacity of porous concrete frost were conducted at Slide Mountain, Sand Harbor, and Milford. Test results were variable but they do indicate that porous concrete frost retards infiltration and that infiltration decreases as moisture content of the frost increases. Infiltration tests were not made on stalactite, granular and concrete frost types. No concrete frost could be located on the days when infiltration was tested. The loosely packed vertical ice spires of stalactite frost and the slightly cemented, porous character of granular frost probably do not have an adverse effect on infiltration. Table 10. Results of infiltration tests of frozen soil depth percent initial final infiltration Locat i on (in.) moisture volume volume, , ( i n./hr.) (ml .) (ml .)— SIide Mountai n porous concrete 14+ 28.4 70 31 1.11 porous concrete 14+ 27.1 70 18 1.48 porous concrete 14+ 25.4 70 13 1 .63 Sand Harbor porous concrete 2 29.4 70 4 1.88 porous concrete 1.5 58.6 70 34 0.97 control (unfrozen) 70 0 11 .61 M i 1 ford porous concrete 1 39.2 70 55 0.43 control (unfrozen) 70 0 120.00 control (unfrozen) 70 0 3.75 1/ after 15 minutes 129 Infiltration tests of unfrozen soils were run within a short distance of the frozen soil infiltration sites. There was a great difference between the infiltration capacity of unfrozen and frozen soils within a given area. When comparisons of infiltration rates between areas are attempted, it should be kept in mind that there are definite differences in bulk density, texture and structure of s o i 1 from one area to another. Infiltration rates of porous concrete frost generally exceeded 1 inch per hour. According to Haupt (1967), the U. S. Weather Bureau (1950) states that the highest measured rate of actual rainfall that occurred during the third largest rain-on-snow flood on record on the east side of the Sierras was 0.50 inch per hour. Therefore, porous concrete frost may be more significant, hydrological 1y , on the west side of the Sierras where hourly intensities of rainfall are greater than on the east side of the Sierras. Additional water contributed by snowmelt, when added to the rainfall, may be enough to exceed the in filtratio n capacity of porous concrete frost and cause overland flow. 130 Hydrophob i c s o i1 observat i ons Water-repellent soils were observed in many areas on the east side of the Sierras. Observations showed that water-repellent conditions are not as common at Deans Ridge, Constantia and Pimentel Meadows as at Spooner Summit, Sand Harbor and Slide Mountain. Water-repellent frozen soil was most often encountered in fine sandy loam but soils with textures as coarse as gravelly sand have been found to be water-repellent. All frost types except stalactite were found in water-repellent soil. Many times frozen soil was found to be water-repellent after it had been dried. There is no clear relationship between frozen soil and water- repellency. Occasionally, water-repellent soil was found directly beneath a frozen layer of so il, indicating that the water-repellent soil retarded percolation and allowed moisture above the repellent layer to increase to a point that a coherent, hard mass of frost could form in the soil when soil temperature reached 32° F. This relationship was seen more often in litter layers. In the case of litter, it appeared that the initially dry water-repellent litter gradually absorbed water from top to bottom and this moist layer froze when the litter reached an unknown moisture content and the temperature of the litter reached 32° F. The frozen layer gradually became thicker as the depth of the moist layer increased and sub sequently froze. 131 Conclus f ons of Winter of 1968-1969 The importance of the presence or absence of a snowpack in determining the occurrence of soil frost cannot be overemphasized. Soil freezing occurred when the snow was less than a foot deep. When snow conditions allowed freezing, litte r depth determined the type of soil frost. A 1 to 2 inch litte r layer that completely covered the soil usually prevented all frost types except frozen litter. Areas with little or no litter were generally frozen v/ith granular or porous concrete frost that was thicker than frost found in litte r covered areas. Vegetative type was of lit tle consequence as long as the vegetation produced a litte r layer that covered the ground. When frost occurred in sheltered, forested areas, it usually ranged from 1 to 3 inches thick, with 4 to 5 inch depths unusual, and depths of 6 or more inches rare. At least 14 inches of frost was found on a windswept slope at Slide Mountain, but the total area occupied by windswept ridges and saddles is usually only a small percentage of the total land area. The time of year had a substantial effect on frost occurrence. Soil freezing passed through a 3 period cycle during the winter of I968-I969. Period One began in late September and ended in early December. During this time, the area and depth of frost steadily increased to a maximum in early December. Period Two began in early December with the f ir s t major storm of the season and ended in mid-March when nearly all frozen ground had thawed. Period Three began in mid-March and ended when the last snow had melted. During this last period, frost was found only around the edges of snowbanks. 132 During Period One (increasing frost occurrence) the first soil frost was noted on September 21. The early frost consisted of 0.5 to 1.5 inches of granular frost that was always found in areas without lit te r and under shallow snowbanks. Later in the period, frost was always found beneath the snow regardless of ground cover. Stalactite and porous concrete frost were not encountered until October 16, but no stalactite frost was noted after December k. Frost occurrence and depth increased as the area covered by snow increased so that by early December, soil frost that averaged 2 to 3 inches deep could be found at elevations above 5^*00 feet. Several conclusions may be drawn from Period One: (1) granular frost was the firs t recognized frost type, (2) granular, stalactite and frozen litter frost types dominated the period, (3) stalactite frost was not observed until the soil had become moist from fall rains or melting snows, (^) snow depths throughout the period usually did not exceed 12 inches, (5) porous concrete frost formed early in the season, but it was restricted to elevations above 7500 feet, (6) the frequency of frost occurrence increased as aspect changed from south through east to north. Period Two began in early December with the firs t large storm of the winter. The snow that fell during this storm and others that soon followed caused a major change in frost distribution. Soil frost had reached its maximum areal extent by early December, but 133 rather than remain stable, most of the frost thawed during December. Prior to early December, the thin snowpack did not allow the soil frost to thaw, but this trend was reversed during Period Two as snow depths rapidly reached record proportions. By mid-January, lit t le frost remained in areas between 5000 to 7000 feet. However, areas below 5000 feet at the eastern limit of the east side coniferous forests remained frozen throughout the period. Observations made over 7000 feet indicated that these areas were beginning to thaw. No single event marked the end of Period Two. The period was ended rather arbitrarily in mid-March after little frost could be found between 5000 and 10,100 feet in elevation. By this time, the only remaining frost was found at the higher elevations on windswept ridges and saddles. The maximum winter snow depth was recorded during Period Two. On February 27, 20k inches of snow were recorded at the west end of Tahoe Meadows. During February and early March, snow depths above 8000 feet consistently exceeded 150 inches in the area of Slide Mounta in . The following conclusions were drawn from Period Two: (1) stalactite frost did not occur during this period, (2) the occurrence of granular frost decreased and the occurrence of porous concrete frost increased, (3) low elevation plots with a shallow or fluctuating snowpack remained frozen throughout the period but conclusions 1 and 2 were still valid for these areas, 134 (A) the depth of all frost types decreased with time, (5) most areas were frozen under a shallow snowpack at the beginning of the period, but these areas quickly thawed when a deep snowpack was established, (6) soil frost thawed most rapidly between the elevations of 5000 to 7000 feet on the east slope of the Sierras (the Sierra Nevada mixed conifer forest is generally confined to this elevation zone), (7) elevations below 5000 feet on the east slope remained frozen throughout the period, (8) sites above 7000 feet thawed less rapidly than areas at elevations below 7000 feet but were generally thawed by the end of the period, (9) below 7000 feet, at least 12 inches of snow was needed to allow thawing of soil frost and to prevent freezing, and, (10) as elevation increased above 7000 feet, more time and a greater depth of snow was needed to allow thawing of the so il. During Period Three, granular frost was found around the edges of melting snowbanks. Stalactite frost again appeared during this period. The three period concept may be a suitable means of gauging the danger of flooding during the winter. Concrete frost, the greatest contributor to flood runoff, was rarely encountered during the winter. Its presence might have been noted more often except that the low elevation areas where this frost type is most likely to occur, were not studied very intensively. 135 Results from infiltration studies showed that porous concrete frost accepted water at a rate exceeding rainfall intensities that normally occur during the winter on the east side of the Sierras. Concrete frost was probably restricted to low elevations where the snowpack was thin or absent, the soil had become wet from melting snow and a ir temperatures were well below 32° F. Where wind blew snow off the soil surface, there was lit t le water left in the remaining snow to wet the soil and consequently porous concrete frost formed. The minimum amount of snow that was required to prevent freezing depended primarily upon elevation. As frost depth and elevation increased, a greater depth of snow was needed to allow thawing of the soil. At low elevations, 12 to 18 inches of snow was usually suffi cient to initiate thawing, but several feet of snow were needed at elevations above 8000 feet. In some areas of Slide Mountain, snow depth was influenced by vegetation. Forest openings covered with brush collected more snow than nearby forests. However, this relationship may not be valid for large brushfields where wind is able to redistribute snow after i t has fallen. No clear relationship between water-repe11ency and soil freezing was found. When water was available, water-repellent soil gradually became moist enough to allow soil frost to form. A few times water- repellent soil was found directly beneath frozen soil, indicating that the water-repellent soil caused moisture to collect in the wettable soil and subsequently freeze when the soil temperature 136 reached 32° F. On the majority of observations, wettable soil was found beneath the frozen layer. The maximum area covered by frost and the maximum flood danger occurred in late November and early December. This danger diminished after the fir s t major snowstorm of the winter dropped several feet of snow on the ground. Land management practices that maximize snow depth and litte r cover will reduce the occurrence of frost and the average depth of frost during winters similar to those experienced in 1967~1968 and I 968-I 969. Although multiple use resource practices often disturb the forest floor, well managed practices should not be removed from the lis t of treatments that the land manager may choose from to best utilize wildlands. A thick litte r layer is most important during Period One when there is a very thin cover of snow on the ground. The presence of litter at this time will reduce the occurrence of porous concrete and concrete frost, both possible contributors to flood runoff. A deep snow cover that rapidly deepens during the early part of Period Two will allow thawing of any frost that may have formed during Period One. During Period Two, the importance of litte r is over shadowed by the depth of snow on the ground. Two winters of field work revealed that 5 site factors have the greatest influence on frost occurrence. Frost occurrence is primarily determined by snow depth which in turn is influenced by aspect, elevation and slope. Litter depth determines the type of frost that w ill form when soil temperatures reach 32° F. The type 137 of vegetation has little or no influence on frost occurrence as long as the vegetation produces enough litte r to cover the ground. Wind influences frost occurrence only on saddles and ridge tops that are exposed to the full force of wind. 138 LITERATURE CITED American Society of Civil Engineers. 1949. Hydrology Handbook. Committee on Hydrology of the Hydraulics Division. A.S.C.E. Manuals of Engineering Practic No. 28. 184 p. Anderson, H. W. 1947. Soil freezing and thawing as related to some vegetation, climatic and soil variables. J. Forestry 45:94-101. Beskow, C. 1935- Soil freezing and frost heaving. Sverig Geologiska Undersoking. Ser. C. 375, 26(3): 1-242. Swedish with English summary. pp 222-242. Review by H. W. Anderson in J. Forestry 45:94-101. 1947. Brink, V. C ., J. R. Mackay, S. Freyman, and D. G. Pearce. 1967. Needle ice and seedling establishment in southwestern B ritish Columbia. Can. J. Plant Sci. 47:135“139. Chow, V. T. 1964. Handbook of Applied Hydrology. McGraw-Hill Book Co., New York. n.p. Dilworth.J. R. 1965. Log scaling and timber cruising. 1965 Ed. Oregon State Univ. Book Stores Inc., Corvallis, Oregon. 448 p. Ferguson, H., P. L. Brown, and D. D. Dickey. 1964. Water move ment and loss under frozen soil conditions. Soil Sci. Soc. Amer. Proc. 28:700-703. Geiger, R. 1965. The climate near the ground. 4 Ed. Harvard Univ. Press, Cambridge, Mass. 611 p. Hale, C. E. 1950. Some observations on soil freezing in forest and range lands of the Pacific Northwest. Pacific Northwest Forest S Range Exp. Sta. Res. Note 66. 17 p. ______1951. Further observations on soil freezing in the Pacific Northwest. Pacific Northwest Forest & Range Exp. Sta. Res. Note 74. 8 p. Hart, G. 1963. Snow and frost conditions in New Hampshire under hardwoods and pines and in the open. J. Forestry 61:289-289. Haupt, H. F. 1967. In filtra tio n , overland flow, and soil move ment on frozen and snow-covered plots. U. S. Forest Service. Water Resources Research. 3(0:145-161. Hussain, S. B. 19 6 8 . Soil and cover characteristics that influence erosion and floods on eastside Sierra Nevada. Mas ter's Thesis. Univ. of Nevada. Reno, Nevada. 139 Janson, L. E. 196*4. Frost penetration in sandy soil. Trans. Royal Inst. Technol. Stockholm, Sweden. Nr. 231. Civil Eng. 10. 168 p. Kienholz, R. 19^0. Frost depth in forest and open in Connecticut. J. Forestry 38:3^6-350. Krumbach, A. W. , Jr., and D. P. White. 196*1. Moisture, pore space and bulk density changes in frozen soil. Soil Sci. Soc. Amer. Proc. 28 :*422-*425. Li, T. 1926. Soil temperature as influenced by forest cover. School of Forestry, Yale Univ., New Haven, Conn. Review by C. F. Kortian in Ecology 9:102-103- 1928. MacKinney, A. L. 1929- Effects of forest litter on soil tempera ture and soil freezing in autumn and winter. Ecology 10: 312-321 . McGlashan, H. D., and R. G. Briggs. 1939- Floods of December 1937 in Northern California. U. S. Geological Survey. Water Supply Paper-8*<3. *<97 p. Megahan, W. F . , and D. R. Satterland. 1962. Winter in filtratio n studies on abandoned and reforested fields in central New York. Eastern Snow Conf. Proc. 7:121-132. Pierce, R. S., H. W. Lull, and H. C. Storey. 1958. Influence of land use and forest condition on soil freezing and snow depth. Forest Sci. *4:2*46-263 . Post, F. A., and F. R. Dreibelbis. 19**2. Soil infiltration of frost penetration and microclimate on the water relationships of woodland, pasture, and cultivated soils. Soil Sci. Soc. Amer. Proc. 7:95-10*4. Stoeckeler, J. R ., and S. Weitzman. i 960. Infiltration rates in frozen soils in northern Minnesota. Soil Sci. Soc. Amer. Proc. 2*4:137-139. Taber, S. 1930. The mechanics of frost heaving. J. of Geol. 38 : 303-137. Townsend, T. W. 1966. Plant characteristics relating to the desirability of rehabilitating the Arotostaphylos patula- Cecmothus velutinus-Ceccnothus prostratus association on the east slope of the Sierra Nevada. Master's Thesis. Univ. of Nevada. Reno, Nevada. Trimble, G. R .f Jr., R. S. Sartz, and R. S. Pierce. 1958. How type of soil frost affects infiltration. J. Soil and Water Conserv. 2:81-82. U. S. Dept, of Agriculture. 1968. Water supply outlook for Nevada as of April 1, 1968. Soil Conservation Service. Reno, Nevada. ______. 1989- Water supply outlook for Nevada as of April 1, 1969- Soil Conservation Service. Reno, Nevada. Weitzman, S., and R. Bay. 1963. Forest soil freezing and the influence of management practices, northern Minnesota, Lake States For. Exp. Sta. Res. Paper LS-2. 8 p. Young, L. E., and E. E. Harris. 1966. Floods of Jan.-Feb. 1963 in northern California. U. S. Geological Survey. Water Supply Paper-1830-A. b l l p. 1A1 1 / 2/ APPENDIX 1.-- WEEKLY SOIL TEMPERATUREAND SNOW DEPTH OF EACH TEMPERATURE PLOT STATION i 2 3 THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 (In c h e s ) DATE (In c h e s ) Snow Depth ‘ Snow Depth !' Snow Depth jj - - (Inches) jj 9 / 2 2 / 6 7 51 50 49 49 49 0 ' 5 , 50 50 50 50 0 54 51 55 52 53 0 9 / 2 9 / 6 7 55 53 5 2 51 49 0 54 54 55 52 50 0 57 65 6 0 54 54 0 1 0 / 6 / 6 7 33 38 38 41 42 0 40 41 39 42 48 0 43 45 41 43 51 0 1 0 / 1 3 / 6 7 49 47 46 45 46 0 , 49 49 49 46 46 0 50 62 51 48 49 0 1 0 /2 0 /6 7 46 42 42 43 45 0 46 46 46 44 46 0 48 57 49 46 48 0 1 0 / 2 7 / 6 7 46 42 41 42 45 0 44 44 44 44 46 0 47 57 48 45 48 0 1 1 / 3 / 6 7 46 43 42 41 44 0 45 44 46 43 45 0 47 51 47 44 47 0 1 1 / 1 0 / 6 7 45 42 41 41 44 0 43 43 43 42 45 0 46 51 48 43 47 0 1 1 / 1 7 / 6 7 42 41 41 41 44 0 42 42 42 42 44 0 45 48 44 43 47 0 1 1 / 2 0 / 6 7 41 39 33 39 44 0 40 40 39 40 44 0 42 41 42 41 46 0 1 1 / 2 7 / 6 7 32.5 32 32 35 41 0 32.5 3 1 .5 32.5 35 40 0 34 43 33 35 42 0 1 2 / 1 / 6 7 32 32 32.5 34 39 11 34 34 32 35 40 11 36 21 32 25 40 10 1 2 / 8 / 6 7 33 32.5 33 34 39 25 35 35 33 36 39 25.5 36 32.5 34 36 40 20 1 2 / 1 5 / 6 7 33 33 33 35 38 21 34 35 33 36 39 21.5 35 30 33 35 39 16 1 2 / 2 3 / 6 7 33 32.5 33 34 38 30 34 34 32.5 35 38 30 25 32.5 33 35 28 19 1 / 5 / 6 8 33 33 34 35 37 23.5 34 35 33 35 38 23 25 31.5 33 34 38 13.5 1 / 1 2 / 6 8 33 33 33 34 37 33 34 35 33 35 37 33 25 32 33 24 37 25.5 1 / 1 9 / 6 8 34 33 34 34 37 27.5 34 34 33 35 37 26.5 35 32.5 34 34 37 18 1 / 2 6 / 6 8 34 33 33 34 37 25 34 34 33 34 37 26 35 32.5 33 34 37 17 2 / 2 / 6 8 33 33 33 34 36 54 34 34 33 34 37 50.5 35 32.5 24 34 36 31 2 / 1 0 / 6 8 33 33 33 34 36 52 34 34 33 34 37 51 25 33 34 24 36 33.5 2 / 1 6 / 6 8 33 33 33 34 36 50.5 34 34 33 34 37 49.5 35 25 34 34 36 31 2 / 2 2 / 6 8 33 33 33 34 36 41 34 34 33 34 37 39.5 34 33 34 24 36 2 5 .5 3 / 1 / 6 8 33 33 33 34 36 36 34 34 33 34 36 32 35 33 34 34 36 18 3 / 9 / 6 8 33 32.5 33 34 35 40 34 34 33 34 36 39 34 32.5 34 24 35 17 3 / 1 5 / 6 8 33 33 33 34 36 45 34 34 33 34 36 41 35 32.5 34 24 36 22 3 / 2 2 / 6 8 33 33 33 34 36 44 33 34 33 34 36 40 35 33 34 34 35 2 2 .5 3 / 2 9 / 6 S 33 33 33 34 35 37 34 34 33 34 36 32.5 25 37 34 34 36 15 4 / 5 / 6 8 33 33 33 34 35 33 34 34 33 33 36 29 35 43 34 34 36 10 4 / 1 9 / 6 8 34 33 33 34 35 25 34 34 33 34 36 21 34 44 36 34 36 T 4 / 2 6 / 6 8 33 3 3 33 34 35 22 34 34 33 34 38 20.5 40 54 45 36 36 0 5 / 3 / 6 8 33 3 2 .5 3 2 .5 33 34 15 34 33 33 33 35 10 45 7 3 51 41 39 0 5 / 1 0 / 6 8 33 33 33 33 24 2.5 42 39 40 38 37 0 4 4 55 48 41 41 0 5 / 1 6 / 6 8 39 38 37 26 36 0 40 37 39 37 38 0 42 52 45 39 40 0 5 / 2 4 / 6 8 40 38 37 38 39 0 39 38 38 38 39 0 42 55 45 40 43 0 -C _C -C STATION 4 5 O . ^ 6 o ' ? V * THERMISTOR 1 2 3 4 5 o 2 1 2 3 4 5 0 2 1 2 3 4 5 O j $ u > l 1) c ? 2 ) i c —- DATE to 9 / 2 2 / 6 7 76 56 57 54 55 0 52 53 54 51 51 0 64 62 55 55 54 0 9 / 2 9 / 6 7 so 57 6 0 58 55 0 54 55 59 52 51 0 65 63 58 57 54 0 1 0 / 6 / 6 7 50 47 47 47 51 0 42 45 42 44 48 0 44 48 42 43 42 0 1 0 / 1 3 / 6 7 89 52 54 5 2 51 0 47 49 48 46 48 0 57 54 50 48 50 0 • 1 0 / 2 0 / 6 7 64 50 52 5 0 50 0 43 45 45 45 48 0 54 49 45 45 48 0 1 0 / 2 7 / 6 7 70 49 50 48 50 0 42 4 4 44 43 46 0 48 44 43 44 48 0 1 1 / 3 / 6 7 55 48 48 47 49 0 42 43 44 41 44 0 50 45 44 42 47 0 1 1 / 1 0 / 6 7 57 46 46 45 48 0 41 43 44 41 44 0 49 44 43 41 46 0 1 1 / 1 7 / 6 7 50 46 46 45 47 0 42 43 43 42 44 0 44 43 42 42 46 0 1 1 / 2 0 / 6 7 44 43 42 42 47 0 40 42 41 40 44 0 42 40 40 40 46 0 1 1 / 2 7 / 6 7 38 37 36 37 42 0 35 36 32.5 36 41 0 3 1 .5 31.5 31 34 43 0 1 2 / 1 / 6 7 32 37 36 37 41 12 35 36 34 35 40 17.5 20.5 32 32 34 41 10 1 2 / 8 / 6 7 33 37 36 37 40 23.5 36 37 36 37 40 3S 31.5 34 33 35 40 23 1 2 / 1 5 / 6 7 32 36 36 37 40 19.5 36 37 36 37 40 2 6 .5 31 34 34 35 40 19.5 1 2 / 2 3 / 6 7 32.5 36 35 36 38 IS 36 37 35 37 39 39 31.5 33 33 24 39 3 1 .5 1 / 5 / 6 8 30.5 35 35 35 38 20 36 37 36 36 39 36.5 22.5 34 34 25 39 2 2 .5 1 / 1 2 / 6 8 32 35 34 35 37 30 36 35 36 36 39 46 22.5 34 34 35 39 32.5 1 / 1 9 / 6 8 33 35 35 35 37 23 36 36 36 36 39 23 32.5 34 34 35 33 25 1 / 2 6 / 6 8 32.5 35 34 35 37 22 36 37 35 36 38 31 32.5 34 34 34 38 24 2 / 2 / 6 8 32.5 33 34 35 36 32 35 36 35 36 38 64 22.5 34 34 34 38 49 ' 1 2 / 1 0 / 6 8 33 35 34 35 36 41 36 36 35 36 3S 60 ! 22.5 34 34 38 4 8 .5 2 / 1 6 68 33 35 35 35 37 39 36 36 35 36 38 6 0 32.5 34 34 35 37 4 8 .5 2 / 2 2 / 6 8 32.5 34 34 34 36 27 37 36 35 35 38 48 32.5 34 33 34 36 34 3 / 1 / 6 8 33 34 34 34 36 19 35 36 35 35 38 4 1 .5 3 2 .5 34 34 34 36 26 3 / 9 / 6 8 32.5 34 34 34 36 13 35 36 35 35 37 41 22.5 34 34 24 36 36 3 / 1 5 / 6 8 33 34 34 34 36 35 36 35 35 38 47 32.5 34 34 34 36 2E , 31 APPENDIX 1. - - (CONTINUED) 1**3 APPEND!X I - (CONTINUED) -C l _c ■ _C 1 CL,__ STATION _ 10 11 12 Q-—- THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 I s c (In c h e (In c h e DATE S n o w D CO Snow D« 1 2 / 1 / 6 7 34 34 36 36 43 6 .5 25 34 34 33 43 7.5 36 37 34 33 42 11-5 1 2 / 8 / 6 7 33 34 26 26 42 5 35 25 34 29 43 8 36 37 34 38 42 29 1 2 / 1 5 / 6 7 25 24 25 32.5 41 3.5 29.5 28.5 2£ .5 35 42 7 36 36 34 38 41 26 1 2 / 2 3 / 6 7 32 29.5 31.5 31 38 4 31 31 30 34 40 11 36 36 34 37 40 33 1 / 5 / 6 8 32 31.5 32.5 33 38 T 31 30 29.5 35 39 9 36 36 34 37 40 16 1 / 1 2 / 6 8 31 30.5 31.5 32 37 5 29.5 29 29.5 34 38 9 36 36 34 37 39 33.5 1 / 1 9 / 6 8 33 32.5 34 32.5 37 T 33 32 22 35 38 T 36 36 34 37 39 22 1 / 2 6 / 6 8 32 32 33 33 37 0 ; 32.5 32 31.5 35 37 T 36 35 34 36 39 24 2 / 2 / 6 8 32 32 33 33 36 10 ! 32.5 32 32 34 37 14 35 35 34 37 38 37 2 / 1 0 / 6 8 32.5 32.5 33 33 35 13 32.5 22.5 J / 35 37 15 35 35 35 37 38 38 2 / 1 6 / 6 8 32.5 32.5 33 33 36 11 33 22.5 22 25 37 14.5 35 35 35 37 38 33 2 / 2 2 / 6 8 32.5 32.5 33 34 36 4 34 33 32.5 25 37 6 34 35 34 36 37 26 3 / 1 / 6 8 44 40 41 37 36 0 40 33 40 37 37 T 34 35 34 36 37 20 3 / 9 / 6 8 34 34 35 26 37 11 35 34 34 37 37 9 33 34 34 36 36 9 3 / 1 5 / 6 8 33 33 34 35 37 5 34 33 33 36 37 6.5 34 34 34 36 36 7 3 / 2 2 / 6 8 33 33 33 35 37 4.5 34 33 33 36 37 6 34 34 34 36 36 4 3 / 2 9 / 6 8 53 49 46 40 36 0 47 52 52 39 37 0 54 49 61 43 37 0 4 / 5 / 6 8 41 39 39 33 38 0 41 40 40 29 39 0 42 40 64 40 40 0 4 / 1 9 / 6 8 4c 45 42 23 39 0 42 44 42 39 40 0 46 43 57 41 41 0 4 / 2 6 / 6 8 5 0 48 46 41 29 0 5 0 51 51 41 39 0 54 49 80 45 41 0 5 / 3 / 6 3 57 53 51 47 41 0 53 48 54 45 41 0 58 51 86 48 43 0 5 / 1 0 / 6 8 72 50 60 46 43 0 49 ■ 49 50 45 42 0 6 0 50 84 47 44 0 5 / 1 6 / 6 8 50 51 46 43 42 0 43 43 44 42 42 0 56 49 78 46 44 0 5 / 2 4 / 6 8 65 42 53 43 44 0 45 43 47 43 43 0 53 46 76 45 45 0 -C _c _c CL' - CL'—- STATION 13 14 15 A 2 ® s C C THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 | c D W Inchi l Uc C*— c C CO DATE • CO CO 9 / 2 2 / 6 7 62 6 2 5 0 53 52 0 61 55 59 54 56 0 58 61 64 54 56 0 9 / 2 9 / 6 7 65 66 63 55 53 0 70 61 62 58 58 0 63 70 65 59 59 0 1 0 / 6 / 6 7 50 48 51 45 50 0 6 0 55 51 45 47 0 44 46 48 45 43 0 1 0 / 1 3 / 6 7 61 63 58 50 50 0 7 3 59 58 50 53 0 58 79 64 52 52 0 1 0 / 2 0 / 6 7 58 56 55 47 49 0 82 53 78 51 52 0 53 56 55 51 52 0 1 0 / 2 7 / 6 7 58 51 51 45 49 0 63 51 64 50 51 0 52 56 54 50 52 0 1 1 / 3 / 6 7 55 51 50 44 48 0 58 52 59 51 52 0 52 58 57 50 52 0 1 1 / 1 0 / 6 7 53 49 50 43 47 0 57 51 58 49 50 0 51 65 62 48 51 0 1 1 / 1 7 / 6 7 48 47 48 43 47 0 6 3 57 57 49 49 0 49 61 57 47 50 0 1 1 / 2 0 / 6 7 43 41 42 41 47 0 41 43 44 44 46 0 43 43 43 44 49 0 1 1 / 2 7 / 6 7 35 32 36 35 43 0 48 42 49 42 43 0 44 60 49 40 45 0 1 2 / 1 / 6 7 34 34 36 36 42 11 35 35 35 39 41 4 35 34 35 39 43 6 1 2 / 8 / 6 7 35 34 36 37 42 30 32 32 31.5 36 39 2 33 3 1 .5 31.5 37 42 4 1 2 / 1 5 / 6 7 35 34 36 36 41 24 39 31.5 40 32.5 35 T 29 39 32.5 35 39 T 1 2 / 2 3 / 6 7 35 33 36 36 40 34 32.5 31.5 32.5 32.5 34 T 32 32 31 32 36 T 1 / 5 / 6 8 34 34 36 36 40 27 39 33 37 35 36 0 3 2 .5 34 33 35 38 0 1 / 1 2 / 6 8 34 33 35 35 39 34 42 32.5 47 34 35 0 33 49 37 34 37 T 1 / 1 9 / 6 8 34 34 35 35 39 23 54 44 48 37 37 0 35 47 41 36 37 0 1 / 2 6 / 6 8 34 33 35 35 39 19 48 36 44 38 40 0 34 35 33 38 40 0 2 / 2 / 6 8 34 33 35 35 38 46 33 32.5 32.5 34 35 4 33 32 32.5 34 37 9 2 / 1 0 / 6 8 34 33 35 35 38 44 34 34 33 36 36 4 34 3 2 .5 33 35 37 10 2 / 1 6 / 6 8 34 34 35 35 38 45.5 33 33 3 2 .5 36 36 6 34 33 33 36 37 9 2 / 2 2 / 6 8 34 33 34 34 37 33 48 45 49 40 38 0 48 63 46 37 37 0 3 / 1 / 6 8 34 33 35 34 36 24 43 44 50 42 41 0 45 53 46 42 40 0 3 / 9 / 6 8 34 33 34 34 36 15 35 36 34 38 39 1 36 33 34 37 39 7 3 / 1 5 / 6 8 34 33 34 24 35 12 34 33 36 36 36 T 34 3 2 .5 33 36 38 3.5 3 / 2 2 / 6 8 34 34 34 34 37 7 41 34 40 35 36 T 34 41 33 36 37 T 3 / 2 9 / 6 8 51 62 49 26 36 0 54 52 54 43 41 0 50 51 53 42 39 0 4 / 5 / 6 8 44 44 42 38 39 0 47 41 43 40 40 0 41 42 41 40 40 0 4 / 1 9 / 6 8 52 54 48 39 40 0 54 42 47 40 40 0 47 46 46 39 41 0 4 / 2 6 / 6 8 62 65 55 42 41 0 53 47 52 43 42 0 51 54 51 43 41 0 5 / 3 / 6 8 8 2 69 76 46 42 0 69 49 60 47 45 0 59 57 62 47 44 0 5 / 1 0 / 6 8 76 70 89 46 44 0 61 49 62 47 46 0 59 62 55 46 45 0 5 / 1 6 / 6 8 71 67 69 45 44 0 51 48 56 43 43 0 62 45 52 44 43 0 5 / 2 4 / 6 8 62 60 71 44 46 0 52 45 51 44 44 0 52 51 51 42 45 0 APPENDIX !.-• (CONTINUED) STATION 16 17 18 THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 (In c h e s ) { (In c h e s ) | (Inches) j] Snow Depth)! Snow Depth;! DATE Snow DepthS 9 / 2 2 / 6 7 60 6 3 61 56 57 0 59 61 58 57 58 0 83 66 80 63 64 0 9 / 2 9 / 6 7 64 68 73 60 58 0 67 67 77 6 0 58 0 93 78 90 71 66 0 1 0 / 6 / 6 7 52 55 58 43 53 0 53 55 60 49 54 0 69 57 67 50 55 0 1 0 / 1 3 / 6 7 6 0 65 76 56 55 0 64 63 74 56 55 0 89 77 86 66 59 0 1 0 /'2 0 '6 7 55 73 65 52 54 0 55 57 69 51 54 0 80 69 76 58 58 0 1 0 / 2 7 / 6 7 52 64 57 50 54 0 52 53 61 49 54 0 67 60 68 52 52 0 1 1 / 3 / 6 7 52 61 61 50 53 0 53 54 59 50 52 0 65 63 65 55 56 0 1 1 / 1 0 / 6 7 51 60 64 48 51 0 54 53 61 48 52 0 72 66 69 50 54 0 1 1 / 1 7 / 6 7 51 57 63 47 50 0 51 52 58 47 51 0 74 67 72 51 52 0 1 1 / 2 0 / 6 7 44 44 44 44 49 0 46 46 45 44 50 0 48 44 47 44 49 0 1 1 / 2 7 / 6 7 42 47 53 40 45 0 43 44 47 40 47 0 56 55 54 41 45 0 1 2 / 1 / 6 8 37 36 35 40 43 11 39 40 35 39 45 8 .5 33 35 34 36 42 9 .5 1 2 / 3 / 6 7 36 36 35 39 42 23 33 39 36 39 43 25.5 33 36 33 35 40' 18.5 1 2 / 1 5 / 6 7 36 35 35 38 41 17 33 38 35 38 42 20 33 34 33 34 39 15 1 2 / 2 3 / 6 7 36 34 35 37 40 25 38 38 35 38 42 26 33 35 33 34 38 22 1 / 5 / 6 8 35 32.5 33 36 39 10 35 37 35 38 40 25 33 33 33 34 37 1 6 .5 1 / 1 2 / 6 8 34 32.5 33 36 38 28 36 37 35 38 40 29 33 32.5 33 34 37 2 6 .5 1 / 1 9 / 6 8 34 33 33 36 33 15.5 35 37 83 38 39 20 33 33 33 34 37 18 1 / 2 6 / 6 8 34 39 33 36 38 12 35 36 34 36 39 13 33 33 32.5 33 36 15 2 / 2 / 6 8 34 33 32.5 35 37 31 34 34 32.5 35 37 30 33 32.5 33 33 36 19 2 / 1 0 / 6 8 35 34 33 35 37 28 35 36 34 36 37 30 33 33 33 33 36 2 6 .5 2 / 1 6 / 6 8 35 34 34 35 37 36.5 35 36 34 36 33 24 33 34 32.5 33 36 2 2 .5 2 / 2 2 / 6 8 42 51 35 34 36 16 34 35 35 35 36 20 3 2 .5 35 32.5 3 2 .5 35 14 3 / 1 / 6 8 46 51 50 41 40 0 43 42 56 39 38 0 56 47 55 42 40 0 3 / 9 / 6 8 37 35 35 33 40 6 37 33 35 37 39 9 34 36 34 36 40 9 3 / 1 5 / 6 8 35 34 36 36 35 T 35 35 33 36 38 T 33 34 | 39 34 37 T 3 / 2 2 / 6 8 39 43 43 36 33 0 40 40 48 33 38 0 45 41 45 38 39 0 3 / 2 9 / 6 8 57 62 65 45 42 0 50 68 48 41 0 72 61 71 56 45 0 55 4 / 5 / 6 8 45 48 51 42 43 0 45 45 65 42 42 0 56 49 56 44 46 0 4 / 1 9 / 6 8 48 53 56 42 43 0 43 47 63 43 43 0 69 52 69 52 43 0 4 / 2 6 / 6 8 55 64 7 2 45 44 0 57 55 97 47 44 0 81 66 86 59 51 0 5 / 3 / 6 8 58 66 67 49 47 0 5S 56 96 49 46 0 82 64 88 60 54 0 5 / 1 0 / 6 8 56 65 68 49 48 0 55 54 84 48 47 0 78 60 86 57 55 0 5 / 1 6 / 6 8 54 59 64 46 47 0 57 53 87 48 46 0 78 58 80 58 53 0 5 / 2 4 / 6 8 5 0 56 55 45 45 0 51 50 76 46 48 0 69 51 75 52 54 0 .e■ _c _c Q--—- Q.'—' Q--— STATION 19 v r 20 © 21 C’ « Q -C Q x THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 * g l g * S c —' C —' e ' DATE in LO en 9 / 2 2 / 6 7 67 57 55 54 0 55 53 53 54 52 0 82 63 65 56 56 0 9 / 2 9 / 6 7 68 62 60 - 60 0 62 59 55 56 52 0 80 69 75 62 57 0 1 0 / 6 / 6 7 47 42 41 _ 50 0 46 45 44 45 49 0 69 51 54 47 50 0 1 0 / 1 3 / 6 7 6 0 52 53 - 49 0 53 52 5 0 50 49 0 70 62 68 54 52 0 1 0 / 2 0 / 6 7 55 49 49 - 49 0 50 48 47 48 48 0 69 68 62 49 50 0 1 0 / 2 7 / 6 7 56 47 47 - 49 49 46 46 47 48 0 57 S3 53 46 49 0 0 1 1 / 3 '6 7 61 48 49 _ 43 0 50 47 46 46 47 0 58 54 57 46 48 0 1 1 / 1 0 / 6 7 65 47 49 _ 48 0 43 46 45 45 47 0 56 52 57 44 47 0 1 1 / 1 7 / 6 7 61 46 48 - 47 0 46 46 44 44 46 0 54 49 60 44 46 0 1 1 / 2 0 / 6 7 42 40 40 _ 47 0 42 42 41 42 46 0 44 43 43 41 45 0 1 1 / 2 7 / 6 7 49 35 36 - 44 0 37 35 35 36 43 • 0 36 36 36 34 41 0 1 2 / 1 / 6 7 32.5 33 34 _ 42 7 35 35 36 37 42 7 .5 34 35 34 36 39 15 1 2 / 8 / 6 7 33 33 34 _ 41 15 35 35 34 37 41 19 34 35 35 36 39 35 1 2 / 1 5 / 6 7 30.5 32 33 - 40 13.5 34 33 35 35 41 15.5 34 35 35 36 38 24 1 2 / 2 3 / 6 7 31.5 31.5 33 - 39 15 34 33 34 35 39 23 34 35 36 35 38 37 1 / 5 / 6 8 31 31.5 33 _ 38 9.5 32.5 31.5 34 34 38 13.5 34 34 36 35 38 . 31 1 / 1 2 / 6 8 31.5 31.5 32.5 - 37 17 33 32 34 34 38 20 34 34 36 35 37 37 1 / 1 9 / 6 8 32 32 33 _ 37 12 34 33 34 34 37 15 34 35 36 35 37 34 1 / 2 6 / 6 8 32 32 33 - 37 9 34 33 34 34 37 13 34 35 35 35 37 32 2 / 2 / 6 8 _ 32 33 _ 37 16 33 32.5 34 33 37 15 34 35 35 35 36 49 2 / 1 0 / 6 8 32.5 32 33 - 37 21 34 34 34 34 37 27 34 35 36 35 37 49 2 6 1 6 /6 8 32.5 32.5 33 _ 37 24 34 34 34 34 37 25.5 34 35 35 35 36 4 9 .5 2 / 2 2 / 6 8 32.5 32.5 33 - 35 13.5 33 34 33 33 35 15.5 33 35 35 34 36 35.5 3 / 1 / 6 8 32.5 32.5 33 _ 36 7 34 34 33 35 35 7 34 35 35 34 36 28 3 / 9 / 6 8 32 32.5 32.5 - 36 7 33 34 33 34 36 8 34 35 35 34 35 29 3 / 1 5 / 6 8 32 32.5 32.5 36 7 33 33 34 34 36 34 36 35 35 36 29 145 APPENDIX 1.-- (CONTINUED) -C - C. Q.' ' "q_-—' Cl-— STATION 19 *> ? 20 t> w 21 o * THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 Si (In c h * c —' (In c h c I/O S n ow D DATE S n ow D 3 / 2 2 / 6 8 32 32,5 33 _ 36 4.5 33 24 34 36 3 34 36 35 35 36 30 3 / 2 9 / 6 8 57 46 4? 36 T 47 34 | 90 36 T 33 35 34 34 36 14 4 / 5 / 6 8 45 38 39 - 39 0 41 40 37 38 38 0 40 ! 34 J 48 35 37 T 4 / 1 9 / 6 8 51 40 41 - 39 0 43 41 40 40 40 0 54 49 56 43 41 0 4 / 2 6 / 6 8 86 56 46 - 40 0 69 49 43 43 40 0 66 65 75 5 0 43 0 5 / 3 / 6 8 6 0 55 52 _ 42 0 70 43 47 47 42 0 77 73 76 53 46 0 5 / 1 0 / 6 8 68 61 56 - 44 0 54 48 47 47 43 0 98 71 70 SO 48 0 5 / 1 6 / 6 8 57 52 48 - 43 0 62 44 44 44 42 0 71 66 67 51 46 0 5 / 2 4 / 6 8 86 5 0 47 - 45 0 49 44 46 44 43 0 76 60 62 47 47 0 -C JC. -C STATION 22 CL'-' 23 Q.—' 24 Q. v r O w THERMISTOR 1 2 3 4 5 o i 1 2 3 4 5 <=>_£ 1 2 3 4 5 Q S S i S i 8 -5 C —' C — c c DATE tO CO tO CD 9 / 2 2 / 6 7 8 3 76 80 I 60 62 0 77 83 60 62 59 0 70 83 88 59 59 0 9 / 2 9 / 6 7 93 88 78 63 71 0 85 94 6 0 70 61 0 76 92 88 65 61 0 1 0 / 6 / 6 7 66 61 62 50 48 0 60 7 0 45 47 53 0 54 74 70 45 55 0 1 0 / 1 3 / 6 7 84 79 68 54 61 0 78 79 SO 61 54 0 68 90 90 69 55 0 1 0 / 2 0 / 6 7 76 69 69 52 54 0 55 79 47 52 52 0 57 79 81 49 54 0 1 0 / 2 7 / 6 7 63 58 57 51 49 0 56 64 46 47 51 0 51 63 70 46 53 0 1 1 / 3 / 6 7 7 0 64 61 50 49 0 56 72 44 48 49 0 53 70 72 47 52 0 1 1 / 1 0 / 6 7 72 65 55 48 47 0 57 75 43 45 48 0 54 74 76 45 51 0 1 1 / 1 7 / 6 7 67 6 2 6 0 47 48 0 59 69 43 46 47 0 52 73 70 44 50 0 1 1 / 2 0 / 6 7 45 44 44 44 41 0 44 46 42 41 45 0 46 47 45 42 49 0 1 1 / 2 7 / 6 7 42 38 34 39 36 0 34 37 32 34 41 0 33 49 55 34 45 0 1 2 / 1 / 6 7 33 32.5 34 38 35 12 22 32 32.5 35 39 12 34 32 34 36 43 9 1 2 / 8 / 6 7 33 32.5 34 37 34 26 33 32 35 35 39 29 35 33 34 36 42 14 1 2 / 1 5 / 6 7 22.5 31 34 37 34 23 33 30 34 34 38 28 34 26.5 34 35 41 11 1 2 / 2 3 / 6 7 22.5 3 1 .5 33 36 34 33 33 31 34 35 38 35 34 - 33 35 40 IS 1 / 5 / 6 8 32.5 3 1 .5 34 36 34 26 33 31 34 35 37 30 33 28.5 33 35 39 16.5 1 / 1 2 / 6 8 3 2 .5 32 33 35 34 31 32.5 31.5 34 35 37 36 34 30.5 33 35 39 16 1 / 1 9 / 6 8 33 3 2 .5 33 36 34 33 23 32 34 35 36 32 34 33 33 35 38 14.5 1 / 2 6 / 6 8 33 32.5 33 36 34 28 32.5 32 34 34 36 32 34 3 2 .5 3 2 .5 34 38 11 2 / 2 / 6 8 32.5 _ 33 36 34 46 32.5 32 34 34 36 47 33 33 32.5 34 37 17 2 / 1 0 / 6 8 33 33 33 35 34 49 32.5 32.5 34 35 35 55 34 34 32.5 34 37 20 2 / 1 6 / 6 8 33 33 33 36 34 46.5 33 32.5 ■ 34 35 36 5 3 .5 24 34 32.5 34 37 20 2 / 2 2 / 6 8 3 2 .5 33 33 35 33 35.5 32.5 3 2 .5 34 35 35 36.5 34 34 32.5 34 36 19.5 3 / 1 / 6 8 32.5 33 33 35 33 28.5 32.5 3 2 .5 34 35 35 33.5 43 63 3 2 .5 34 36 11 3 / 9 / 6 8 32.5 33 33 - 33 29 22.5 32.5 34 35 35 33 35 34 33 35 38 11 3 / 1 5 / 6 8 33 33 33 35 34 27 22.5 32.5 34 35 35 32 34 33 32.5 34 37 5 3 / 2 2 / 6 8 33 33 34 36 24 25 32.5 3 2 .5 34 35 36 28 34 J 52 33 34 37 4 3 / 2 9 / 6 8 33 4 0 33 35 33 19 3 2 .5 33 34 35 35 26 65 87 80 51 40 6 4 / 5 / 6 8 49 51 34 37 38 9 3 2 .5 ! 53 34 35 35 16 50 56 54 42 43 0 4 / 1 9 / 6 8 61 6 0 56 42 47 0 55 64 34 J 46 39 T 56 77 64 46 45 0 4 / 2 6 / 6 8 86 81 73 46 56 0 70 90 49 55 43 0 70 100 90 53 46 0 5 / 3 / 6 8 91 86 76 52 59 0 73 93 57 58 47 0 75 104 92 57 49 0 5 / 1 0 / 6 8 88 81 73 53 55 0 68 90 60 55 5 0 0 70 101 86 81 51 0 5 / 1 6 / 6 8 76 75 72 50 54 0 69 82 58 55 48 0 69 98 81 53 49 0 5 / 2 4 / 6 8 77 70 72 51 49 0 65 SO 57 51 50 0 64 94 75 49 51 0 - c - c -C STATION 25 26 27 Q.'—' fs c ** r O -C THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 s ^ j o w D Inche Si c —• C DATE to t o 9 / 2 2 / 6 7 8 0 76 51 60 58 0 64 53 53 52 _ 0 59 61 56 54 56 0 9 / 2 9 / 6 7 96 8 3 57 66 59 0 66 56 59 54 - 0 65 70 69 58 57 0 1 0 / 6 / 6 7 62 6 0 41 45 51 0 51 43 42 42 0 42 56 47 42 54 0 1 0 /1 3 '67 74 74 46 54 51 0 63 50 51 47 _ 0 59 62 57 51 53 0 1 0 /2 0 67 61 66 39 47 49 0 60 46 46 44 _ 0 44 69 54 48 52 0 1 0 / 2 7 / 6 7 48 61 41 43 48 0 62 45 45 43 - 0 47 49 48 47 52 0 1 1 / 3 / 6 7 50 63 4 0 42 45 0 62 45 46 42 _ 0 5 0 57 66 45 51 0 1 1 /1 0 '6 7 50 6 3 41 41 44 0 54 44 44 41 _ 0 48 51 51 45 50 0 1 1 / 1 7 / 6 7 39 56 38 39 44 0 49 43 42 41 _ 0 49 52 50 45 50 0 1 1 / 2 0 / 6 7 44 47 42 40 43 0 40 41 41 40 _ 0 45 47 46 44 49 0 1 1 / 2 7 / 6 7 31.5 37 3 1 .5 31.5 39 0 40 3 2 .5 32.5 34 - 0 31.5 41 33 34 45 0 146 A P P E N D IX !.-• (CONTINUED) CL-— Q--—- o. s t a t i o n 25 O * 26 C) V) 27 OJS THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 lncn« Si o w D o w D ich es C'-' c c D ATE l/> t/> CO 1 2 / 1 / 6 7 3 1 .5 28.5 32 2 7 .S 28 9.5 30.5 24 32.5 34 . _ 10 34 34 33 36 43 4 1 2 / 8 / 6 7 32.5 30 33 33 37 37 32 25 24 35 - 24 34 33 33 35 42 10 1 2 / 1 5 / 6 7 3 2 .5 27.5 34 33 37 32 30.5 - J 33 24 - 22 32.5 31 27.5 34 41 7.5 1 2 / 2 3 / 6 7 32 2 9 .5 34 33 37 40 31 34 33 34 - 26 32 3 1 .5 30.5 33 39 10 _ 1 / 5 / 6 8 32.5 28 34 33 26 32 32 24 34 35 21 31 29 26 33 38 7.5 1 / 1 2 / 6 8 32.5 29.5 34 33 36 34.5 31.5 24 33 34 - 25.5 31.5 31 30.5 32.5 37 10 1 / 1 9 / 6 8 32.5 32 34 34 36 22.5 32 24 34 34 - 24 32.5 32.5 3 2 .5 33 37 5 1 / 2 6 / 6 8 33 31.5 34 34 36 30 32 24 24 34 - 22 32.5 3 1 .5 32 33 37 0 2 / 2 / 6 8 33 32 34 34 35 4 4 .2 32 24 33 34 39 32 32 32 32.5 36 7 2 / 1 0 / 6 8 33 32 34 34 36 45.5 22.5 24 34 34 - 41. 32.5 3 2 .5 32.5 32.5 36 4 'i A 2 / 1 6 / 6 8 33 32.5 34 24 36 53 32.5 34 34 _ 40 32 32 32.5 33 36 4 2 / 2 2 / 6 8 33 32.5 33 33 34 40 32 24 34 34 - 29 45 47 44 38 37 0 3 / 1 / 6 8 33 33 33 34 35 34.5 32 24 34 34 _ 23 42 45 43 38 40 0 3 / 9 '6 8 3 2 .5 32.5 33 - _ 33 32 34 33 34 - 34 34 34 34 35 39 4 3 / 1 5 / 6 8 33 33 33 34 35 24 22.5 24 34 34 - 28 32.5 32.5 32.5 34 38 T 3 / 2 2 / 6 8 33 33 33 34 35 34 32.5 35 24 34 - 28 38 41 39 34 37 0 3 / 2 9 / 6 8 33 33 33 34 35 34 32.5 25 34 34 - 25 49 48 51 41 38 0 4 / 5 / 6 8 33 33 33 33 35 26 22.5 34 34 34 _ 17 42 43 42 39 40 0 4 / 1 9 / 6 8 33 62 33 34 35 T 32.5 34 33 34 — T 39 42 40 37 40 0 4 / 2 6 / 6 8 3 2 .5 96 32.5 35 34 T 35 j 34 34 33 - 0 42 44 48 41 40 0 5 / 3 / 6 8 7-3 99 59 49 41 0 75 47 46 43 - 0 49 51 55 47 43 0 5 / 1 0 / 6 8 72 91 58 48 45 0 76 46 45 43 - 0 47 46 51 45 46 0 5 / 1 6 / 6 8 7 4 94 61 50 45 0 69 44 44 41 - 0 45 44 55 45 45 0 5 / 2 4 / 6 8 68 83 57 46 47 0 67 43 43 42 0 47 45 54 45 47 0 -n Jc _c STATION 28 CL—' 29 Q-—' 30 Q.—' t, c> v " Q £ THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 o J! o w D In c h e si C '-' C'— DATE i/j CO CO 9 / 2 2 / 6 7 66 70 75 64 66 0 61 69 65 58 62 0 55 6 0 55 55 56 0 9 / 2 9 / 6 7 80 85 86 68 67 0 7 0 81 76 64 6 3 0 59 62 58 56 56 0 1 0 / 6 / 6 7 55 68 59 51 6 2 0 47 52 52 43 68 0 46 48 45 48 53 0 1 0 / 1 3 / 6 7 67 91 73 59 51 0 53 65 64 54 56 0 52 5 3 51 5 0 52 0 1 0 / 2 0 / 6 7 57 78 6 3 54 61 0 49 55 55 47 53 0 48 49 47 47 51 0 1 0 / 2 7 / 6 7 51 65 55 52 60 0 44 47 47 44 52 0 45 48 45 46 51 0 1 1 / 3 / 6 7 56 66 62 5 0 56 0 47 53 52 44 5 0 0 48 47 45 45 49 0 1 1 / 1 0 / 6 7 51 6 2 52 48 56 0 45 47 47 43 49 0 46 47 45 45 49 0 1 1 / 1 7 / 6 7 51 74 56 43 55 0 46 50 51 43 48 0 46 46 45 45 49 0 1 1 / 2 0 / 6 7 48 5 3 49 46 54 0 47 47 47 44 48 0 44 46 44 45 48 0 1 1 / 2 7 / 6 7 33 61 37 37 49 0 32 32 32 32 42 0 3 2 .5 36 33 37 45 0 1 2 / 1 / 6 7 35 3 2 .5 35 37 47 6 .5 33 35 34 35 40 6 .5 36 36 36 39 44 6 .5 1 2 /8 '6 7 34 3 1 .5 34 37 45 5.5 25 34 35 35 40 8 36 37 36 38 43 14 1 2 / 1 5 / 6 7 29.5 22 30.5 33 43 4 .5 33 34 32.5 34 39 8 34 35 35 37 42 11.5 1 2 / 2 3 / 6 7 32 3 0 .5 32 32.5 41 9 33 34 33 34 38 13 35 35 35 37 41 17 1/ 5 / 6 8 3 0 .5 2 9 .5 30.5 34 39 4 .5 34 33 32 33 37 6 34 34 35 36 40 15.5 1 / 1 2 / 6 8 32 29 32.5 32.5 38 5 34 34 32.5 33 37 17.5 34 34 35 36 39 2 1 .5 1 / 1 9 / 6 8 32 39 32 32 38 T 24 34 33 34 37 6 35 35 35 36 39 14.5 1 / 2 6 / 6 8 2 6 .5 38 32 32.5 37 34 34 33 34 36 7 34 35 35 36 39 11 0 2 / 2 '68 32 32.5 32.5 32.5 37 8 34 34 34 34 36 20 34 34 35 35 38 2 3 .5 2 / 1 0 / 6 8 3 2 .5 32.5 32.5 33 37 6 35 34 34 34 36 13 34 35 35 35 38 2 1 .5 2 / 1 6 / 6 8 32.5 32.5 32.5 23 27 4 .5 35 34 34 33 36 12 34 34 35 35 38 21 2 / 2 2 / 6 8 54 74 56 40 38 0 37 33 40 33 35 3 34 34 34 35 37 14 3 / 1 / 6 8 45 59 46 42 43 0 42 41 42 38 39 0 34 38 35 35 36 3 3 / 9 / 6 8 35 33 36 38 43 3.5 36 35 36 35 39 7 35 35 35 36 38 7 3 / 1 5 / 6 8 34 | 62 24 41 0 34 34 33 34 37 T 34 34 35 35 37 4 3 / 2 2 '’68 44 58 44 90 41 o 4 0 ~ L 34 1 40 35 37 T 34 34 35 35 37 2 3 / 2 9 / 6 8 69 90 69 51 45 0 63 63 56 48 41 0 45 49 45 41 39 0 4 / 5 / 6 8 51 59 50 48 48 0 50 46 45 43 44 0 40 42 42 40 41 0 4 / 1 9 / 6 8 58 67 59 48 49 0 60 64 52 45 45 0 41 37 47 39 4 ] 0 4 / 2 6 / 6 8 55 78 5 9 51 50 0 55 78 52 47 47 0 41 43 46 41 42 0 5 / 3 / 6 8 68 95 77 57 54 0 78 84 68 57 52 0 5 0 51 55 45 44 0 5 / 1 0 / 6 8 60 92 77 54 56 0 68 73 62 53 54 0 46 50 49 45 45 0 5 / 1 6 / 6 8 65 97 77 56 54 0 70 76 64 57 53 0 48 48 50 44 45 0 5 / 2 4 / 6 8 65 80 81 52 56 0 71 72 59 53 55 0 44 48 46 44 46 0 147 APPEND JX I.-- (CONTINUED) -C STATION 31 c ? 32 33 T HERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 In ch e ( ( In c h e s ) DATE (In c h e s ) S now D Snow Depth Snow Depth • 9 / 2 2 / 6 7 53 52 52 54 55 0 55 54 56 5 5 53 0 51 52 55 51 49 0 9 / 2 9 / 6 7 56 66 62 56 55 0 61 57 65 53 54 0 54 54 61 52 SO 0 1 0 / 6 / 6 7 43 38 39 46 52 0 47 46 51 47 5 2 0 43 44 44 45 48 0 1 0 / 1 3 / 6 7 49 50 49 49 51 0 55 52 61 52 51 0 49 50 55 47 47 0 1 0 / 2 0 / 6 7 44 42 42 46 49 0 51 49 54 43 50 0 45 46 51 44 46 0 1 0 / 2 7 / 6 7 43 41 41 46 49 0 48 46 49 47 5 0 0 43 44 47 44 46 0 1 1 / 3 / 6 7 42 41 42 44 47 0 47 46 49 46 49 0 43 44 46 42 45 0 1 1 / 1 0 / 6 7 43 44 45 43 46 0 47 45 45 45 48 0 42 44 46 42 45 0 1 1 / 1 7 / 6 7 43 42 42 44 46 0 46 45 47 45 48 0 43 44 44 43 45 0 1 1 / 2 0 / 6 7 43 45 44 44 46 0 44 44 44 44 48 0 42 43 44 42 44 0 1 1 / 2 7 / 6 7 32 3 1 .5 31 37 42 0 33 26 35 37 45 0 35 34 31.5 36 42 0 1 2 / 1 / 6 7 24 32 32 38 41 12 36 37 35 38 44 7 .5 36 35 3 2 .5 36 41 12 1 2 / 8 / 6 7 35 33 33 39 40 23.5 35 37 35 26 43 15 5 36 36 34 37 40 32 1 2 / 1 5 / 6 7 35 33 33 38 40 20 24 36 34 37 42 13 35 35 34 37 40 24 1 2 / 2 3 / 6 7 35 33 33 38 39 26 34 35 24 37 41 17.5 34 34 33 37 40 33 1 / 5 / 6 8 34 33 33 37 38 22 34 34 33 36 40 10.5 36 35 33 36 39 30 1 / 1 2 / 6 8 34 34 34 37 3S 33.5 24 24 36 40 20.5 36 35 33 36 39 40 1 / 1 9 / 6 8 34 34 34 37 38 24.5 34 25 24 36 39 13 36 35 34 36 39 32.5 1 / 2 6 / 6 8 34 34 34 36 38 21 34 35 34 36 39 11 36 35 34 36 38 28 2 / 2 / 6 8 _ _ 34 36 37 41 34 35 34 35 38 26 36 35 34 36 38 50 2 / 1 0 / 6 8 34 34 34 36 37 36 34 35 34 35 38 20 26 35 34 35 38 47 2 / 1 6 / 6 8 34 34 34 36 37 36 34 35 34 36 38 20 36 35 34 36 38 4 4 .5 2 / 2 2 / 6 8 34 34 34 36 36 24 33 33 33 35 36 n 35 34 34 35 33 40 3 / 1 / 6 8 34 34 34 35 36 13 37 37 37 35 36 T 35 34 34 35 37 29 3 / 9 / 6 8 34 34 34 35 36 10 35 36 24 36 39 6 35 34 33 35 36 17 3 / 1 5 / 6 8 34 34 34 35 36 5 34 35 34 36 33 3 35 35 34 35 37 27 3 / 2 2 / 6 8 34 34 35 35 36 4 34 34 24 35 3S 1 35 35 34 35 37 27 3 / 2 9 / 6 8 43 55 54 39 38 0 48 42 52 42 39 0 39 37 33 34 36 T 4 / 5 / 6 8 41 46 47 40 40 0 40 40 41 40 41 0 38 38 41 37 37 0 4 / 1 9 / 6 8 40 48 46 39 41 0 42 42 44 39 41 0 38 38 44 37 39 0 4 / 2 6 / 6 8 40 46 42 42 42 0 42 41 44 41 41 0 40 39 43 39 39 0 5 / 3 / 6 8 52 63 74 47 44 0 52 48 54 45 43 0 46 46 66 43 40 0 5 / 1 0 / 6 8 46 47 47 47 46 0 51 43 58 45 44 0 47 45 58 44 42 0 5 / 1 6 / 6 8 49 52 68 45 46 0 50 48 51 43 43 0 46 45 56 42 42 0 5 / 2 4 / 6 8 44 43 46 46 48 0 49 44 53 43 45 0 46 44 51 44 44 0 -C -C -C Q -— • Q.'—' 36 Q .-~- STATION 34 V " 35 THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 * g c o* _ o_5* c DATE C — ' C ' - ' C'-' lO t n 9 / 2 2 / 6 7 56 61 61 54 55 0 74 66 78 66 69 0 61 58 59 52 51 0 9 / 2 9 / 6 7 58 60 6 2 56 55 0 85 89 S3 73 72 0 6 3 59 64 54 51 0 1 0 / 6 / 6 7 43 42 42 45 51 0 66 72 64 53 63 0 45 44 49 43 48 0 1 0 / 1 3 / 6 7 54 53 55 49 51 0 84 90 82 63 67 0 54 55 62 47 48 0 1 0 / 2 0 / 6 7 50 49 53 47 50 0 84 86 74 63 66 0 54 52 60 44 46 0 1 0 / 2 7 / 6 7 47 47 49 46 50 0 79 77 64 58 64 0 53 53 55 42 45 0 11 / 3 / 6 7 47 48 48 45 49 0 6 3 69 65 60 64 0 52 52 54 42 44 0 1 1 / 1 0 / 6 7 47 46 48 44 48 0 6 3 62 57 54 61 0 48 49 50 40 43 0 1 1 / 1 7 / 6 7 47 46 48 45 48 0 76 78 65 53 59 0 45 45 45 40 43 0 1 1 / 2 0 / 6 7 43 43 44 43 47 0 43 47 47 46 57 0 41 41 41 38 42 0 1 1 / 2 7 / 6 7 32.5 32 33 35 44 0 7 2 66 55 46 45 0 32.5 33 32.5 33 39 0 1 2 / 1 / 6 7 34 33 34 37 43 10.5 33 34 36 38 49 9 .5 32 32 32 34 38 17 1 2 / 8 / 6 7 35 34 34 37 42 21 33 34 35 37 45 14 33 33 34 33 37 3 2 .5 1 2 / 1 5 / 6 7 34 34 33 37 41 17 33 33 32.5 32.5 41 T 33 3 2 .5 33 34 37 26 1 2 / 2 3 / 6 7 34 33 33 36 40 26 3 2 .5 33 33 33 40 5 .5 33 3 2 .5 34 34 37 29 1 / 5 / 6 8 34 33 33 36 40 18.5 70 82 38 37 42 0 34 3 1 .5 33 34 36 32 1 / 1 2 / 6 8 34 33 33 36 39 27.5 48 33 35 36 41 4 .5 33 32 33 34 36 40 1 / 1 9 / 6 8 34 34 33 35 39 23 66 72 46 40 42 0 34 33 34 34 35 39 1 / 2 6 / 6 8 34 33 33 35 38 22 52 47 42 42 47 0 34 33 34 34 35 25 2 / 2 / 6 8 34 33 33 35 38 41 32.5 32.5 34 35 40 11 34 33 34 34 35 64 2 / 1 0 / 6 8 34 34 33 35 38 37 33 33 35 36 41 2 34 34 34 34 35 5 6 .5 2 / 1 6 / 6 8 34 34 33 35 38 36.5 36 35 36 37 41 0 34 34 34 34 35 64 2 / 2 2 / 6 8 34 34 33 35 37 26 68 77 59 45 61 0 34 34 34 34 35 54 3 / 1 / 6 8 34 34 33 35 37 17.5 57 67 54 50 5 0 0 34 34 34 34 35 43 3 / 9 / 6 8 34 34 33 34 37 19 33 38 36 40 48 2 34 34 34 34 34 48 3 / 1 5 / 6 8 34 34 33 35 37 22 58 46 5 3 41 44 0 34 34 24 34 35 48 ] k 8 APPENDIX 1. ■■ (CONTINUED) _C -C STATION 34 Q_-— 35 36 THERMISTOR 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 o J * UC DATE c —' c — C —' in in 3 / 2 2 / 6 8 34 34 33 35 37 19 47 45 47 43 38 0 34 34 34 34 35 48 3 / 2 9 / 6 8 34 34 33 35 36 9 70 7 0 72 56 49 0 34 34 34 34 35 35 4 / 5 / 6 8 40 41 42 38 38 0 49 47 50 47 50 0 34 34 34 33 34 19 4 / 1 9 / 6 8 41 54 53 39 40 0 66 SR 6 3 SO 51 0 4? 43 46 39 36 0 4 / 2 6 / 6 8 48 45 68 41 40 0 55 52 57 51 52 0 51 56 75 39 37 0 5 / 3 / 6 3 52 65 70 47 43 0 74 68 71 58 56 0 67 57 82 47 41 0 5 / 1 0 / 6 8 57 67 90 47 45 0 64 62 66 56 57 0 64 64 93 47 43 0 5 / 1 6 / 6 8 51 58 6 2 46 45 0 59 63 67 54 54 0 53 53 67 45 42 0 5 / 2 4 / 6 8 54 6 2 86 45 46 0 6 0 54 6 0 50 55 0 53 57 72 45 44 0 -C _c STATION 37 Q-— 38 O VI THERMISTOR 1 2 3 4 5 o j 1 2 3 4 5 I s I- c —' c —' DATE in in 9 / 2 2 / 6 7 59 55 58 50 50 0 8 0 72 68 52 52 0 9 / 2 9 / 6 7 58 61 59 52 50 0 60 61 6 2 56 52 0 1 0 / 6 / 6 7 45 44 46 44 47 0 32.5 33 43 39 45 0 1 0 / 1 3 / 6 7 50 5 0 51 47 47 0 69 69 56 44 47 0 1 0 / 2 0 / 6 7 49 49 52 45 46 0 53 58 51 41 44 D 1 0 / 2 7 / 6 7 48 50 5 0 44 46 0 54 60 47 39 43 0 1 1 / 3 / 6 7 49 51 50 44 45 0 50 46 46 38 42 0 1 1 / 1 0 / 6 7 45 46 46 43 45 0 44 46 42 37 40 0 1 1 / 1 7 / 6 7 43 43 44 43 44 0 39 42 41 36 40 0 1 1 / 2 0 / 6 7 40 4 0 40 41 44 T 34 34 35 36 39 5 1 1 / 2 7 / 6 7 32.5 32.5 3 2 .5 37 41 0 28 27.5 30.5 30 36 3 1 2 / 1 / 6 7 34 33 33 37 40 10.5 30 30 32 31 35 23 1 2 / 8 / 6 7 35 35 34 37 40 19.5 32 32 33 32 35 34 1 2 / 1 5 / 6 7 34 34 34 36 39 15.5 31.5 30.5 32.5 35 35 26.5 1 2 / 2 3 / 6 7 33 34 33 36 38 17 31 30 32 32 35 34 1 / 5 / 6 8 33 34 3 2 .5 35 38 16 32 29.5 32.5 32.5 34 33.5 1 / 1 2 / 6 8 33 34 33 35 37 28.5 31 29.5 32 31.5 34 4 5 .5 1 / 1 9 / 6 8 34 34 33 35 37 20.5 33 3 1 .5 34 32.5 34 39.5 1 / 2 6 / 6 8 34 34 33 34 37 20 33 31 33 32.5 34 35 2 / 2 / 6 8 34 34 33 35 37 39 33 30.5 33 33 34 65 2 / 1 0 / 6 8 33 34 33 35 36 41 33 31 33 33 34 70 2 / 1 6 / 6 8 33 34 33 35 36 39 33 31.5 33 33 34 7 3 2 / 2 2 / 6 8 33 34 33 34 35 32 6 3 .5 3 / 1 / 6 8 33 34 33 35 36 2 6 .5 33 33 33 33 34 6 0 3 / 9 / 6 8 33 34 33 35 36 31 33 3 2 .5 32.5 33 34 6 7 3 / 1 5 / 6 8 34 34 33 35 36 3 2 .5 34 33 33 33 34 70 3 / 2 2 / 6 8 33 34 33 35 36 31.5 34 34 33 33 34 70 3 / 2 9 / 6 8 33 34 33 35 36 25 33 33 33 33 34 70 4 / 5 / 6 8 33 34 33 34 36 21 34 33 33 33 34 65 4 / 1 9 / 6 S 33 34 32.5 34 35 13 34 33 33 33 34 55 4 / 2 6 / 6 8 33 34 3 2 .5 34 35 12 34 33 33 33 34 51 5 / 3 / 6 8 44 57 47 35 35 T 33 3 2 .5 32.5 32.5 32.5 37 5 / 1 0 / 6 8 44 44 5 0 39 38 0 33 33 32.5 33 33 25 5 / 1 6 / 6 8 43 44 47 38 38 0 33 33 32.5 33 32.5 17.5 5 / 2 4 / 6 8 41 42 42 39 40 0 34 64 54 35 _34 T J_/ Degrees Fahrenheit. 2/ Inches 3/ Snow covered thermistor between dates indicated by lines. 149 Appendix 2. Summary of soil temperature data collected at each temperature plot near Slide Mountain during winter of 1967-1968. C 0 XJ — 1 • - U — c L. 1- 05 3 a) U- 0 0 0 05 SZ 4-J _ IZ •— O 4—> C. c 05 C in 4-J 05 U) 3 <1) ^ 05 05 i_ .— 4—> L - Plot 2 1 3^.0 32.5 0.3 111 1 i tter + 1.5" soil 2 3*».l 31.5 1 0.5 1" 1 itter 3 32.9 32 1 0.2 0.5" soil A 3*1.3 33 0.8 1" 1i tter + 6" soi 1 5 37.0 35 1 .2 24" s o i1 Plot 3 1 3*i.9 3*i 0.5 1.5" litter 2 32.*» 30 4 1 .1 above surface 3 33.7 32 1 0.8 0.5" 1i tter 4 3*i.3 3*i 0.6 2" 1i tter + 5" soil 5 36.9 35 1.4 24" so i 1 Plot 4 1 32.5 30.5 5 0.6 above surface 2 35.0 33 1.3 3" 1i tter 3 3*1.5 3*i 0.8 1" litter + 1.5" soil 4 35.0 3*i 1.1 1" 1i tter + 5" soil 5 37.2 36 1.6 24" soil Plot 5 1 35.6 35 0.6 above surface 2 36.3 35 0.7 4" litte r 3 35.2 35.2 0.6 above surface 4 35.7 34 0.8 6" soil 5 38.3 36 1 . 1 24" s o i1 “U 32.5 "U 3^.6 1 8 Plot -o 13 o o o o Vn Jr-v-o ro — vn jr-vo ro —- V n S r V o M v n -tr- v o ro vn - t - v o ro Thermi s tor m 1/ U) UJ U) U) OJ U ) U ) Va ) U ) Va J U VO VO VO VO VO VO v o VO VO VO Mean temperature ~ MIO W N) N) V I U UJ UJ Va J vn vo v o ro CO Vn VO VO VO "O -C - v o VO ro (degrees Fahrenheit) COU) -t-U ) CO v a j v n c o o n f o VH CO OO OO o O VO VO VD v o c o ro vo vo ro ro ro \ a ) CJ OJ CJ V a ) U J U ) Va ) C O v o VO VO VO VO v o v o VO VO VO ON — ' \J1 -t- U1 _tr- NJ ro — —< 4r- ro —■ —• o n ro •—* ro vn - t - — * — * o Minimum temperature Vn VH Ul v n v n v n vn (degrees Fahrenheit) MU) — — co ro — — ro ro v n Number of weeks frozen ro — vaj c o c o o o o o o — r o litte 3" o o 0.6 _ O O o o . o o o o Standard deviation of to s i m ro o n q n c h c n c d o n O Jr- 4T- Jr- o n c o c_n vn " O v n o n v n ON temperatures recorded at each thermistor ro —» ro ro —« —>vn —. —. ro o — O ro ro VO -£~ • • ~ CO ~ z • z -c- • • • _ ~ - t - • — Z o vn “ vn z vn vn Vn z v n z ~ —■ CO to — m m * “ ~ z —* — * —• m m * — * — * - cn — — CO O O — • vn + + c r - — — vn — Jr- ro IS) “ • to to to CO O v_n o o o o —* to “ — ■ O __ , __ , . __ _ —• to —* O "O -U "0 ~U -U (Continued) 2. Appendix —• —* —* ---• o o o o o rt rt rt rt r t _ __ _, cn -Cn co ro cn -E" CO ro — cn -E- co ro — cn E “ CO ro — cn -e - co ro — cn -E-CO ro — Thermi stor co CO CO CO CO CO CO CO CO CO CO CO CO CO CO co CO co co CO CO CO CO CO CO Mean temperature — co v i co cn CN co cn co oo cn cn CO -E“ on -E- cn oo cn ro ro CO oo cn (degrees Fahrenheit) X- CO ~~~* CO CD CD on —' —* -E~ ro ON oo ro jn —* cn on ro cn ro U) CO CO CO ro CO CO CO CO CO CO CO co CO CO CO CO CO co CO co CO ro ro ro Minimum temperature on ro —* — ■CD -E- ro —* —* ro on E~ E~ ro -E- ON ON -E* 4r- Co -E- ON OO U3 • • • • • • • (degrees Fahrenheit) cn cn cn cn cn cn cn 9 — to co ro — co — — 7 •E- Number of weeks frozen Standard deviation of to ro -E“ CD -E* ro ro ON -E~ ON ro O O o O ro o O — - ro . ro ro ro temperatures recorded O CO CO ro on ON ON o CD oo cn 4E- o CO -E- O o to cn cd co cn at each thermistor c in -E~ ro ro ro o O CO ro ro ro to to -E- CO D “ o co “ “ ~ ~ ■E- • • • -E- • • ~ » -E" “ — • ~ _ CL CD cn cn cn ~ cn cn cn ~ cn CD —* —•r t c n —* — ■ — ■ —• ” ~ — * ~ — > —» — ■ Material over U) —• —• rt c n o —• — • —• c n —• c n —• i n —- —* —• o rt rt CD o — rt rt- rt o —* —- cn rt o —• — * r t —- o rt r t —•rt thermi stor —•-i rt rt n —•—>r t rt rt o r t —• —•r t r t —•r t —•o CD ro CD —• ro ro CD —• rt r t — CD —»rt rt CD rt —•ro CD rt ro O CL “l 1 r t rt —* ”1 rt rt “i r t n rt 7T CD CD ro ro CD CD —■ t n n “i n /■—, —• n + CJN r t + + ON rt “ CD c n ON CL “l o cn CD —• o CD —» cn — - “D —• v—' o —■ "O “U T3 "U (Continued) 2. Appendix —» —* —# —* o o o o o rt r t r t r t r t ro _, _.. _ _, o VO OO ON vn -t- OJ ro — vn Jr- VO ro — vn jr-vo ro — vn Jr- vo ro — vn -C- VaJ ro — Thermistor VO VO VO VO VO vo VO VO VO VO VO VO VO VO vo vo VO vo VO vo VO VO VO VO Mean temperature Jr- Jr- vo vo 1 VO ro ro 4T- Jr- Jr- Jr- vo ^0 vn ON oo on vn vn ON — O -E- O -t-'vj ON 1 o ro o vn ON VO ON vn ro vo ro vn vo oo ro ON ON (degrees Fahrenheit) W OJ vo vo VO VO VO VO VO VO VO VO vo vo vo vo VO vo vo vo vo vo VO Minimum temperature W UJ — ro vn 1 ro —* o vn ro ro ro ro on vn ro jn Jr- on jr- ro ro Jr- (degrees Fahrenheit) vn vn 1 vn vn vn vn vn vn vn vn vn vn ro OO VO Number of weeks frozen — O — o ro 1 o o o ro ro vn vo vn ro vn ro ro ro ro Jr- jr- vo Standard deviation of —’ ro O o 1 Jr- vn o VO VO ON vo vn Jr--^J Jr- o o ro -C- temperatures recorded at each thermistor ro ro vo Jr- ro ro 1 O —■ ro vn vo ro ON i ro ro ~__~ — • Jr- • • • • • • OO — • — “ Jr- 1 Jr- 5 0 5 oo i o l vn o vn vn i —< —» —» — 1 — —» ~ ~~ “ — to — —» n i —» —* cn — — — 10 1 — to CO co o — — LT) o i — — Material over o r t r t r t —• o 1 —' r t —• o CO co o co o —• r t —> r t o r t i r t r t —• r - r r t r t —• —* —• r t —• —• o o — o —• —• r t —• r t —• rt i r t r t thermi stor —- CD CD fl> r+ —' rt n> r t —■— —• —•—• — > CD r t CD —» CD i n> CD “1 “I rt rt n r t —•—* —» 1 rt n D i n 0) CO n> CD + ■ “1 n + n —■ o Vn + ro CQ O ro vn vn “* CO - CO o o —• CO —• —* o —* ~TD “O “U "O ~U (Continued) 2. Appendix —* —# _# o o o o o rt rt rt rt rt K> ro ro ro ro vn -t- vo ro vn -c -v o N3 — vn jr -v o ro — vn -c- vo ro — vn .c- vo ro — vn -E" VO ro — Thermistor VO vo vo VO vo VO V J vo VO VO vo vo vo vo vo VO vo VO VO VO vo vo vo VO VO Mean temperature — vo vo vn CO -C- VO —* -t- ON Jr- -E- ro ro vo vn vo ro ro ON -E* vn E " VO (degrees Fahrenheit) QN fO -C“ On O —• ON JTOOO o vn OO CO vo vn oo vo vo — •vo vo vo vo vo ro VO VO VO VO ro VO vo vo vo vo vo vo VO vo VO vo VO vo vo VO vo Minimum temperature -t - — ' — » —* on -c- ro ON VO vn _t- ro o ro vn vo vo —•ro vn -E- -E" -E* VO • • • • • • • • (degrees Fahrenheit) vn vn vn vn vn vn vn vn cn — N> O VO -e - vo -E- Number of weeks frozen o o __ o NJ o O co ro — o o o o o o o O O . o o o o Standard deviation of ON ON vo vn — ' '-J O ' ro vo -e - e - -E* co ro vn vo vn •'*0 ro ro O O N U l vo temperatures recorded at each thermistor vn ro QJ to 1 o cu ro on ro ro ro jr- o ro ■E------o CO cr • -t - 1 • cr “ -E- z ~ o • E~ Z ~ ~ • -E* ~ • • • o vn Z i vn o ~ vn ~ vn “ vn vn vn \n in < 1 — < to to — ■ ~ -i to to ~ to ” “ “ i/> o o fD in i CD o in O —• in 1/1 O o o in o o in O i in —• o — rt o to o o —• —• to o — • — - —• — ■ —• — • —' lO o — 1 o in —• — • — » r t —• o — 7T — > —« o —• — « — • —• —• Material over —' c —• — • 1 — • c —« CD —« —• —• —• — > r t r t r t n — 1 —- n —* + —* r t r t r t thermi stor “h ”h CD CD CD DJ QJ —• “1 **T “1 O O “ CD CD + to o to —• o —• —• “U -u "U "O 2. Appendix —• ——- —• —• —■ o o o o o rt rt rt rt rt Co to ro ro ro O CO oo CN cn CO ro —* cn Jr-co to — cn Jr co ro — cn j r co ro — cn jr-co ro — Thermistor o o D CO co co ViJ Oj CO Co co co co Jr VO CO Co CO Co CO VO VO CO i VO VO VO CO Mean temperature —^ VO on cn J=” Jr- Jr- Jr Jr Jr o cn cn CN Jr oo Jr CO CO Jr i j - CO Jr —* D (degrees Fahrenhei t) C —■“* O —* CO Jr- jr* ro cn J^CD co O ro co -c- -J- ro O CD O o CN —* CD CD O. Co CO Co CO CO CO CO CO CO co CO CO CO ro ro CO co ro ro VO i CO CO CO CO M i n imum temperature cr* cn co 4r- ro cn ro ro ro ro N*sl ro o ro cn CN ro ON VD —> i CO ro to o • • • • • i • • • (degrees Fahrenheit) cn cn cn cn cn cn cn cn CH . J r 6 — ro vn vn o 7 CN to Number of weeks frozen N> —•o — o —*—■ ro —* ro CO Co cn co cn ro —» J^-cn Jr o o o o Standard deviation of • • • • 2 8 3 CO ro Jr* ro oo cn 8 CO ro co cn to CD oo — O Jr cn Jr cn temperature recorded at each thermistor to ro ro ro J ------i o ro ON ro 0) ro ro CTN O O o to cn c ro • • • • “ • i • Jr cr • —• ~ • • • Jr ~ ZJ ~ ~ cn cn O cn ~ cn i cn ~ o o — cn cn cn “ CL ~__■ co z i z CO CO < ~ CO - — — CO CD —•—- CO CO o i CO o o CD CO o CO o n — — o —*—■—• —• O —• —- i —* o —•—• CO o —• ——• —• o —• rt rt Material over —•—• —• i —• — •—•— > CO o —* —• —• —*4r- rt rt —•r+ rt rt rt — rt- rt —» c —• —* rt rt rt —* z CD n> thermi stor rt rt rt rt rt rt “t —» rt rt rt + n “1 CD CD CD CD CD 0) ~h CD 01 CD n n “V n n *1 0 ) n n ~ \ 1 o + o o o -f CD + + + O 7 T — ' 7 T Z on o o o O co cn cn cn D O co O CO i/i 10 (/) c o o o “I -t> O CD “K j= ~U ~u “O “U ~D (Continued) 2. Appendix —* —• —- —» —• o o o o o rt rt rt rt rt CO CO CO co Co \J1 x - CO ro ro — cn A 3 2 — cn x - co ro — cn X - CO ro — Cn x - co ro — Thermistor X -c o co x - X- CO CO co co co CO CO CO Co CO CO Co Co co CO CO Co Mean temperature x - oo co on cn c o cn co x - oo cn co x - cn co co ON jr- cn X“ NJ ONCO CO x - (degrees Fahrenheit) kD Ui jr-ui Co ONcn — on CO *■—| On CD CO — t — * ro x - O \JVsJ ON ro W U ) U ) U) CO CO CO co CO CO CO co co co CO CO CO CO CO CO CO CO CO CO CO Minimum temperature Co M N) M fO on X - co ro ro On X~ — •x - x - on cn co CO CO on cn —• —' ro • • • • • • • (degrees Fahrenheit) Cn Cn \J~| Cn vn cn cn — — ro to — Number of weeks frozen vn x- oo CO X- ro o o o o — o o o — ro — ■ — — ■ o — - — o O o Standard deviation of ,6 .3 00^1 — o CO o vd u j vn ro x - oo cn o CO o o to VO ON x - temperatures recorded at each thermistor ro on —• cr O ro ON — o ro on ro co x - ro ro ro ro ro ro cr ro x - z z cd • X- ~ z • * x - z z ~ x - — - ~ -e- re • • • Z ZJ CH cn cn ~ ” z o o o cn tn in CD ~ C/) — ' I ~ in — ■—■» — > — < — » —- —• CD ~ in o O QJ in o — w O — in in qj O — — rt m o —• rt —- —• O — rt rt rt o rt rt rt rt O rt —* —• —-» — — — IT o —- — ■ rt —• —• — • — * rt rt rt —» rt rt rt rt — zr —• —• —• Material over —» —* —- n> rt rt — CD n> CD —- re re (0 re —* rt rt rt —* -1 rt rt T "I “t “I 1 “t “i rt rt rt thermi stor o 0) CD o re CD CD o “l T + o n “1 7T 7T + + Xj _. O — “ • t/r vn o in ~ — in O ro — lt 8 3. 2 7 . 1 si + gravel + soil 1" 1.5 7 28 32.6 1 38 Plot Plot 37 1 33.4 32.5 32.5 33.4 1 37 Plot 1 -o o CD r t s c 3 ZT vo r t (D 3 O' i n i r r t O CD — < CD — • CD 3 — ■ 3 i n —• r t x > 3. 3 5 . 6 soil 6" 1.1 5 32.5 30 34.3 32.8 5 4 3. 2. 1 16 ." otn log rotten 0.5" 1.6 12 27.5 31.7 2 2 33.9 32.5 32.5 33.9 2 3. 3. 4 . 15 soil 1.5" 0.8 4 30.5 32.8 35 3 34 37.0 35.1 5 4 f t i n CD 32.5 33.0 3 JT-VaJ N3 —• Thermi stor CD r t r t 3 (Conti 3 O 3 —• X > 3 CD O CD O CL 3 z CD DJ CD —« VJ W Ul Ul w Mean temperature r t i n O QJ v n 0 0 vaj v>o \_o c - h i n (degrees Fahrenheit) 3 0 r t w v f i s ; n v j CD O i n CD 3 3 CL £ i n O CD — £ - h i n CL 3 CD O O W W Va I W V J Minimum temperature 3 3 < 3 M —• N3 (D CD CD (degrees Fahrenheit) O CL 3 r t O 3“ ~ t> CD CD CL “ l CD CD CD 3 -i Number of weeks frozen CL CD —• —• < 3 — u O CD i n 3 - t i 3 r t 0 . 2 1itter 2" 0.6 . 2" soil 24" 1.3 . 15 lter litte 1.5" 0.4 . 2 lter litte 2" 0.5 . 2" soil 24" 1.7 3 i n r t 3 soil 6" + r litte 1.5" 1.0 OOOO Standard deviation of 3 3 " CD O O O CD W C T 'V ) O ' temperatures recorded 3 £ 3 in CD 3 c at each thermistor £ —. 3 £ = r in CD CD CD r t c r CD 3 O —• N) —•O —- —* 7T 3 CD ■ P- • • ~ 0) • “ Ln Ul r t r t —• ~ —■ O — ■ 3 in — CD — CD O rt in —■rt r t 3 3 O —•rt O —•rt Material over D " IO CD —■CD — rt O CD CD r t 3 —■rt 3 thermi stor z r O CD 3 —• CD “ t» + + 3 CD 3 X O in in — r t 3 ■O 3 V2 • CD 3 O " rt QJ —• £ in rt in 3 O CD CD ID r t — 3 - O 157 Appendix 3. Maps of winter of 1968-19&9 study sites Figure 6 3 .--Canyondam study site. General reconnaissance conducted in area indicated by arrow. U.S.G.S., Almanor, California, Quadrangle, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile. Figure 6A.--Copperva1e study site. General reconnaissance conducted in crosshatched area. U.S.G.S., West- wood, California, Quadrangle, 15 minute series, contour interval bO feet, scale: 1 inch to 1 mile. 158 Appendix 3. (Continued) Figure 65.--Susanvi11e Summit study site. General reconnaissance conducted in area indicated by arrow. U.S.G.S., Susanville, California, Quadrangle, 15 minute series, contour interval ^0 feet, scale: 1 inch to 1 mile. --Deans Ridge study site, Arrow indicates location of transects. U.S.G.S., Fredonyer Peak, California, Quadrangle, 15 minute series, contour interval kQ feet, scale: 1 inch to 1 mile. Figure 67.--Milford study site. Numbered arrow indicates location of transect. U.S.G.S., Milford, California, Quadrangle, 15 minute series, contour interval kO feet, scale: 1 inch to 1 mile. 160 Appendix 3. (Continued) Figure 68.--Constantia study site. General reconnaissance conducted in crosshatched area. Arrow indicates location of transects. U.S.G.S., Chilcoot, California, Quadrangle, 15 minute series, contour interval AO feet, scale : 1 inch to 1 mile. Figure 69.--Yuba Pass study site. General reconnaissance conducted in areas indicated by arrows. U.S.G.S., Sierraville and Sierra City, California, Quadrangle, 15 minute series, contour intervals 40 and 80 feet, scale: 1 inch to 1 mile. Appendix 3. (Continued) Figure 70.--Dog Valley study site. General reconnaissance conducted in areas indicated by arrows. U.S.G.S., Loya1 ton , California, Quadrangle, 15 minute series, contour interval 40 feet, scale: 1 inch to 1 mile. Figure 71.--Sand Harbor study site. Arrow indicates location of transect. U.S.G.S., Carson City, Nevada, Quadrangle, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile. 1 6 2 Tayyiracfc l. Figure 7 2 .--Slide Mountain study site. Numbered arrows indicate location of transects. General reconnaissance con ducted in area indicated blank arrows. U.S.G.S., Mt Rose, Nevada, Quadrangle, 15 minute series, contour interval ^0 feet, scale: 1 inch to 1 mile. n aruor (Continued) 3. Appendix Figure 73.“Spooner Summit study site. Numbered arrows indicate location of transects. General recon naissance conducted in area indicated by blank arrows. U.S.G.S., Carson City, Nevada Quadrangle 15 minute series, contour interval 80 feet, scale: 1 i nch to 1 mile. Figure ~]l\.--Luther Pass study site. General reconnaissance conducted in area indicated by arrow. U.S.G.S., Freel Peak, Ca1ifornia-Nevada , Quadrangle, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile. Figure 75.--Cloudburst Canyon study site. General reconnaissance conducted in area indicated by arrow. U.S.G.S., Freel Peak, Ca1ifornia-Nevada, Quadrangle, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile. Figure J 6 .--Bootleg Canyon study site. Arrow indicates location of transects and area of general reconnaissance, U.S.G.S., Fales Hot Springs, Ca1ifornia-Nevada, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile. Figure 77.— Pimentel Meadows study site. Arrow indicates location of transects. U.S.G.S., Fales Hot Springs, California- Nevada, 15 minute series, contour interval 80 feet, scale: 1 inch to 1 mile. Appendix k . Soil frost transects (winter I 9 6 8 -I 3 6 9 ) T ransect: SLT-1 Area: Slide Mountain Date: 10-16-1968 E1evat ion: 8570 West end of Tahoe Vegetat ion: scattered lodgepole Meadow pine poles and sma11 sawt i mber Point Snow Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) ( in .) ( in.) (in.) 1 2.5 0 0.5 granular S85W 5 2 2 0 1.5 granular S60W 0 3 2 0 0.5 g ranu 1 a r South 0 h 3 0 0.5 granular S15E 5 5 1 0 1.5 granular S05E 5 6 1.5 0.5 0.5 granular S20E 5 7 5 T 1 granular S10E 5 8 3 T 0.5 granular S35E 5 9 1 0 0 S10E 5 10 0 1 0 S10E 5 T ransect: SLT-2 Area: Slide Mountain Date: 10- 16-1368 Elevation: 9000 Slide Mountai n Vegetation: mountain hemlock, Campground lodgepole pine, and whitebark pine poles Point Snow Litter Frost Frost Type Aspect Slope Depth Depth Depth (percent) (in.) (in.) (in.) 1 5 0 0.5 stalactite N60W 10 2 2 0 0 N65W 5 3 3 0 0 N70W 5 k i* 0 0 S85W 5 5 2.5 0 0 West 5 6 2 0.5 0 S70W 10 7 6 1 0 slow 10 8 2.5 0 0 S25W 10 9 3 0 0.5 g ranu1 a r S25W 10 10 5 0 0 S30W 10 167 Appendix b. (Continued) Transect: SLT-3 Area: Slide Mountain Date: 10- 16-1968 Elevation: 8500 0.75 mile west of Vegetat i on: lodgepole pine, red Mt. Rose Ski Area f i r and Western white pine poles and small sawtimber Point Snow L i tter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in .) (in.) (in .) 1 2 0.5 0.5 granular N70W 5 2 2 1.5 1 frozen 1i tter N80W 5 3 3 0.5 0.5 stalactite N60W 5 1 granula r b 3 2 1 frozen 1i tter N05W 5 5 2.5 1 0.5 frozen 1i tter N25W 5 6 2.5 1 0.5 frozen 1i tter N15W 5 7 2 0.5 0.5 frozen 1i tter N05E 10 8 2 log 1 frozen litte r log S70W 10 9 1 2 0 ------S/f 5V/ 10 10 1.5 0 0 ------North 5 1 6 8 Appendix A. (Continued) T ransect: SLT-A Area: Slide Mountain Date: 11-1-1968 Elevat ion: 8600-8960 South end of Vegetat ion: point 1 to 3: Tahoe Meadow lodgepole pine Western white pine poles; point A to 2k mountain hemlock, lodgepole pine poles and Western white pine; point 25 to 26 Western wh i te pine poles Point Snow Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) (in.) (in.) 1 0 0 0 N75E 5 2 0 1 0 N60E 10 3 0 0 3.5 porous concrete N30E 10 A 0.5 0.5 1 porous concrete N20E 10 5 0 1.5 1 .5 frozen 1i tter N10E 15 6 0 0.5 2 granular North 15 7 0 1.5 1.5 frozen 1i tter N10E 15 8 5 0 3.5 porous concrete N10E 20 9 3 0 3.5 porous concrete N10E 20 10 0 3 3 frozen 1i tter North 20 11 0 0 2.5 porous concrete North 20 12 0 A 2 frozen litter North 20 13 1 .5 0.5 1 .5 porous concrete North 20 1A 0 3 1 frozen 1i tter North 20 15 3 0 3 porous concrete North 20 16 0.5 3.5 2.5 frozen 1i tter North 20 17 0 0.5 A granular North 20 18 0 0.5 0 North 20 13 2.5 0 A porous concrete North 20 20 A 0 1 .5 granular North 20 21 1 .5 0.5 3.5 granular North 20 22 0 0 1 granular North 20 23 3.5 0 2 granular North 15 2A 0 0 2.5 porous concrete North 5 25 0 0 0 S10E 5 26 0 0 0 S10E 5 169 Appendix b. (Continued) T ransect: SLT-5 Area: Slide Mountain Date: 11- 15-1968 Elevat ion: 7650 Lake Tahoe Overlook Vegetati on: Jeffrey pine, red fir, and white fir poles, sma11 and large sawtimber Point Snow L i tter Frost Frost Type Aspect Slope Depth Depth Depth (percent) ( in .) (in .) (in. ) 1 b.5 1 1 stalact i te S70E 15 0.5 granular 2 3.5 1 1 frozen 1i tter S70E 15 3 A.5 1 1 frozen 1i tter S20E 15 b 3 b 1 frozen 1i tter S40E 15 5 b.5 2 1 frozen litte r S65E 15 6 rock rubble 7 6 3 1 frozen 1i tter S80E 15 8 6 1 1 frozen 1i tter S75E 15 9 b.5 b 1.5 frozen litte r N80E 15 10 6 2.5 1.5 frozen 1i tter S65E 10 Transect: SLT-6 Area: Slide Mountain Date: 11- 15-1968 Elevation : 7080 0.1 mile west of Vegetat i on: Jeffrey pine poles Christmas Tree and small sawtimber Point Snow L i tter Fros t Frost Type Aspect Slope Depth Depth Depth (percent) (in.) (in .) (in.) 1 1 .5 6 2 frozen 1 i tter S70E 10 2 1.5 1 .5 1 frozen 1 i tter S20E 10 3 2 0.5 0.5 granular S20E 10 b 1 2.5 1 frozen 1i tter S50E 10 5 0.5 1 1.5 granular N30E 10 6 1 6 2 frozen 1i tter East 5 7 0 1 0 East 5 8 0.5 1 1 frozen 1i tter S60E 5 9 1 3 1.5 frozen 1i tter S65E 5 27 Transect: SHT-1 Area: Sand Harbor Date : 11- 15-1968 E1evat ion : 6350 0.25 miles northeast Vegetat i on: Jeffrey pine, wh? te of park entrance fir, and i ncense- 10 cedar, sma11 and large sawtimber 1-■- L- ' " * " " '■ — ■— ■■ ■ " Point Snow Litter F rost Frost Type Aspect S 1 ope Depth Depth Depth (percent) ( in .) (in.) ( in .) 1 1 .5 0 0 N80W 20 2 2 0 0 N80W 20 3 1 T 0 Wes t 20 A 1 0.5 0 West 20 5 1 1.5 0 S75W 20 6 1 .5 0 0 Wes t 10 7 1 3 0 West 20 8 1 T 0 Wes t 20 9 0.5 3-5 0 West 20 10 1 T 0.5 granu1 a r West 20 171 Appendix b. (Continued) T ransect: DRT-1 Area: Deans Ridge Date: 11-27-1968 Elevat ion: 5^00 Vegetat ion: sugar pine, Jeffrey pine, incense-cedar, and white fir saplings, poles, and smal1 and large sawtimber Point Snow Litter Frost Frost Type Aspect Slope Depth Depth Depth (percent) ______(in.) (in.) (in.)______ 1 2 0 1 .5 granular N70E 15 2 1.5 0.5 0.5 frozen 1i tter NAOE 25 3 1 2 0.5 frozen 1i tter N60E 60 b 1 0 1 stalact i te N60E 60 5 1 0 1 stalacti te N70E 60 6 1 0.5 0.5 frozen 1 i tter N70E 60 7 0 1.5 0 S70E 60 8 1.5 0 1 granular Eas t bO 9 1.5 0 1 granular N80E bO 10 1 0 1 .5 stalact i te N70E bO 11 1 1 1 frozen 1 i tter N70E bO 12 1 0 1 granular N70E bO 13 2 0 0.5 granular N70E bO 172 Appendix A. (Continued) Transect: DRT-2 Area: Deans Ridge Date: 11- 27-1968 E 1evat i on: 5350 Vegetat i on: sugar pine, Jeffrey pine, white fir, and incese-cedar, sapling poles, small and large sawt i mber Point Snow Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) ( in .) (in.) (in.) 1 0.5 2 0 S70E 10 2 1 0.5 1 granu1ar S70E 10 3 0.5 0 1.5 granular S70E 5 A 0 0 0 S60E 5 5 0.5 1 0 S60E 5 6 1 .5 1.5 1 frozen litter S50E 5 7 0 1 0 S60E 5 8 0 0.5 0 S60E 5 9 1 0 1.5 stalactite East 0 10 1.5 0 1 granular S80E 5 11 1 0.5 2 frozen 1i tter N60E 5 « — I 173 Appendix k. (Continued) T ransect: PHT-1 Area: Pimentel Meadows Da te: 11-29-1368 E1evat ion: 7500 Vegetat ion Jeffrey pine and white fir large sawt imber Point Snow L i tter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) ( in .) ( in .) 1 0 0.5 2.5 granular S30E 20 2 0 0 1 granular S30E 20 3 0 0 0 S50E 15 A 0 0 0 S50E 15 5 0 0 0 S50E 15 6 0 2 0 SbOE 10 7 0 5 0 N80E 10 8 0 0 1.5 granular East 15 9 0 3 3 frozen litter N50E 60 10 1 0 2 granular N20E 60 11 0 2.5 1.5 granu1ar HkOE 60 12 1 0 k granular N20E 60 13 2 0 3 porous concrete N50E 60 5 granular 1 1 5 granular N10W 60 Appendix (Continued) Transect: SLT-8 Area: Slide Mountain Date : 12-4-1968 E1eva t ion : 6950 Next to temperature Vegeta t ion : scattered Jeffrey plots 1^4 and 15 pine poles Point Snow L i tter Frost Frost Type Aspect Slope Depth Depth Depth (percent) ( in .) ( in.) (in.) 1 0 2.5 0 S30E 10 2 0 0 0 S36E 15 3 0 3 3 frozen 1 i tter S20E 15 A 2.5 2.5 2.5 frozen 1 i tter South 15 5 0 0.5 0.5 sta 1 act i te South 15 6 0 1 1 frozen 1i tter South 15 7 0 0 1 stalact i te South 15 8 0 0 2.5 granular South 15 9 1 1 1 frozen 1i tter South 15 10 0 1.5 1 .5 frozen 1i tter South 15 175 Appendix A. (Continued) T ransect: SLT-9 Area: Slide Mountain Date: 12-A-1968 E1evat ion: 6950 Above temperature Vegetation: White fir and plots 1 and 2 Jeffrey pine poles and sma11 sawt i mbe r Po i nt Snow Litter Frost Frost Type Aspect S1 ope Depth Depth Depth (percent) (in .) (in.) (in .) 1 1.5 1 1 frozen 1 i tter N10W 15 1.5 granular 2 6 1 .5 0 N20W 20 3 A 1.5 1 frozen 1i tter N60E 20 A 3 1.5 1.5 frozen 1i tter N20W 20 5 2.5 1 1 frozen litter North 30 2.5 granular 6 3 1 1 frozen 1i tter North 30 7 2.5 1 1 frozen 1i tter N30E 30 8 3.5 1 1 frozen 1i tter NAOE 30 2.5 granular 9 2 2.5 1.5 frozen 1i tter nAow 30 10 2 2.5 1.5 frozen 1i tter N30W 50 176 Appendix A. (Continued) Transect: SLT-10 Area: Slide Mountain Date: 1 2-4 -1 9 68 E1evat i on: 9000-9200 Mt. Rose H ighway Vegetat ion: point 1 to 10: Summi t lodgepole pine and whitebark pine poles, poi nts 11 to 12: lodgepole pine, mountain hemlock, whitebark pine poles, and small sawtimber Point Snow Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) ( in .) ( in .) ( in .) 1 16.5 0 1.5 porous concrete S30E 20 2 9.5 0 1.5 porous concrete S10E 20 3 10.5 0 2.5 porous concrete S10E 20 A 7.5 0 2 porous concrete S30E 20 2 granular 5 9 0 2.5 porous concrete S20E 20 6 114.5 0 0.5 porous concrete S60E 20 7 16 0 0 slow 20 8 8 0 2 porous concrete S20E 20 9 13 A. 5 1 frozen 1i tter S20E 20 10 20 1 0 S20E 20 11 15 0 .5 porous concrete North 20 12 36 0 1 .5 porous concrete North 20 Appendix k. (Continued) Transect: CTT-1 CTT-2 CTT-3 Area: Constantia Date: 12- 13-1968 Elevation: ^600 Vegetation: CTT-1 Jeffrey pine poles, and small sawtimber CTT-2: Jeffrey pine and whi te fi r saplings and poles CTT-3: Jeffrey pine poles and bitterbrush Point Snow Li tter Frost Frost Type Aspect Slope Depth Depth Depth (percent) (in.) ( in.) (in.) CTT-1 1 0.5 2 1 .5 frozen 1i tter N20W 25 2 0.5 2 1 .5 frozen 1i tter N50W 25 3 0.5 3 0 N70W 10 0.5 1 0.5 granular N20E 10 5 0.5 2 1 frozen 1 i tter Eas t 50 6 0.5 2 1.5 granular S80E 50 7 0.5 1.5 1.5 frozen 1 i tter N75E 50 CTT-2 1 0.5 2 1.5 frozen litter N25W 50 2 1 T 2 granular N05W 50 3 0.5 2 1.5 frozen 1i tter North 50 0.5 2 1 granular North 50 5 0.5 2.5 1.5 frozen 1i tter N10W 50 CTT-3 1 1 0.5 1.5 porous concrete S50E 25 2 0 0.5 1.5 porous concrete S*t0E 20 3 0.5 0.5 1 granular SA0E 20 h T T 2.5 porous concrete S30E 20 5 0.5 0.5 1 granula r S45E 15 6 0 2 1.5 frozen litter S20E 15 7 0 1.5 1 frozen 1 i tter S30E 10 8 1 2.5 1 .5 frozen litter SkOE 10 9 0.5 2 1 frozen 1i tter S50E 15 10 1 0.5 1 granular S65E 20 178 Appendix 1*. (Continued) Transect: MGT-1 Area: M i 1 ford Date: 1-3-1969 Elevation: 6050 West side of Mil ford Vegetat ion: Jeffrey pine Grade summit sap 1i ngs Point Snow Li tter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) ( in .) (in.) 1 ~nr~ 0.5 0 ------S30E 5 2 u 1 0 ------S10E 5 3 16 3 0 ------S50E 5 1* 20.5 2 0 ------S70E 5 5 20 1 0 ------N20E 5 6 18 2 0 ------S60E 5 7 17 1 0 ------South 5 8 16 1 0 ------S20E 5 9 W* 2 0 ------S30E 5 10 22.5 3 0 ------S30E 5 Transect: MGT-2 M i 1 ford Date: 1-3-1969 E 1evat i on: 5920 East side of Mi1 ford Vegetation: Jeffrey pine, white Grade summit f i r and Doug 1as-f i r sapli ngs, poles, smal1 and large sawt imber Point Snow Li tter Frost Fros t Type Aspect Slope Depth Depth Depth (percent) ( in .) (in.) ( in.) 1 ] 6 0 1 porous concrete N50E 15 2 19 3 1 frozen 1litter N60E 20 3 15 0.5 0 East 20 1* 17 1 .5 0 S70E 20 5 15.5 1 0 East 20 6 U.5 2 0 N80E 20 7 12.5 3 0 N80E 20 8 11* 2 0 N50E 20 9 li* T 0 S50E 20 10 13 1 0 S50E 20 Appendix k. (Continued) T ransect: MGT-3 Area: Milford Date : 1-3-1969 E 1evat ion: 5600 1 mile below summi t Vegetat ion: white fir, Jeffrey of Milford Grade pine and Douglas- fi r sap 1 i ngs , and large sawtimber black oak Point Snow L i tter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) ( in .) ( in .) 1 10.5 0.5 0 N80W 10 2 10 0.5 0 N60W 10 3 13.5 1 0 N*»0W 10 h ]k 1 0 N30W 10 5 7 1.5 0 N*»0W 10 6 13 T 0 N30W 10 7 13 0.5 0 N20W 15 ] 80 Appendix b. (Continued) T ransect: SGT-1 SGT-3 Area: Spooner Date: 1-4-1969 Elevation: 7120 Near summit of Vegetat i on: SGT-1: Spooner Grade white f ir , red f i r and Jeffrey pine poles and smal1 sawt i mber SGT-3: white fir and Jeffrey pine poles and sma11 sawt imber and bitterbrush Point Snow Litter F ros t Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) ( in .) ( in .) SGT-1 1 23 0 2 granular N10W 30 2 20 2 0.5 frozen 1 i tter North 30 3 21.5 0.5 1.5 granular North 30 b 23.5 0 1 granular North 30 5 2 b T 1 granular North 30 6 2b T 1 .5 g ranu1 a r N10W 30 7 1 b b 0.5 frozen 1i tter N10W 30 SGT-3 1 13 2 0 S30E 10 2 17.5 2 0 S30E 10 3 16 1 0 S30E 10 b 18 1 0 S30E 10 5 23 1 0 S30E 10 6 25 0.5 0 S30E 10 181 Appendix 4. T ransect: SGT-2 Area: Spooner Date: 1-/4-1969 Elevat ion : 6640 1 mi 1e east of Vegetat ion : white fir, Jeffrey Clear Creek pine, sugar pine, Campground and incense-cedar poles and sma11 sawtimber Poin t Snow L i tter Frost Frost Type Aspect Slope Depth Depth Depth (percent) (in.) ( in .) ( in .) 1 19 2 0 ------N60E 50 2 21 1 0 N60E 50 3 15.5 1 0 ------N60E 50 4 13.5 2 0 ------N60E 50 5 15.5 1 0 ------N50E 50 6 12 1.5 0 ------S80E 50 7 7 2 0 ------S60E 50 8 20 0 0 ------S80E 50 9 24 0 1 porous concrete N80E 50 10 23.5 T 0 ------East 50 11 14 0.5 0 ------S60E 50 12 15 T 0 ------S30E 50 13 17 T 0 ------S20E 50 18 2 Appendix 4. (Continued) T ransect: SLT-11 SLT-12 Area: Slide Mountain Date: 1- 18-1969 E1evat i on: 7500 0.2 mile north of Vegetat i on: SLT-11 : highway maintenance Jeffrey pine poles station and small sawtimber SLT-12: white fir, Jeffrey pine, red fir poles and small sawtimber Point Snow Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) (in.) (in .) SLT-11 1 22 3 0 granular South 5 2 20 1 0 S10E 5 3 20 1.5 0 S50E 5 4 12 1.5 0 porous concrete S40E 5 5 9 6 1 .5 frozen 1i tter S20E 10 6 3 0 1 granular S20E 15 4 porous concrete 7 25 1 0 S20E 25 8 14 1 0 S20E 50 9 14 TI/ 0 S10E 50 10 9 0 2 granular S10E 50 11 0 0 2 granular S10E 60 12 0 0.5 2 granular South 60 13 5 0 2 porous concrete S30E 60 SLT-12 1 19 1 .5 0 N30E 15 2 40 2 0 N70E 10 3 36.5 3 0 N60E 10 4 32 1.5 0 N60E 10 5 26 TI/ 0 N20W 10 6 32 1 0 N60W 10 1/ Trace of snow 183 Appendix h. (Continued) T ransect: SLT-13 Area: Slide Mountain Date : 1-18-1969 Elevation: 8200 0.5 mile east of Vegeta t ion: mountain hemlock Mt. Rose Ski Area red f i r and Western white pine poles Point Snow Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) (in.) (in.) 1 61 0 1 .5 porous concrete N10E ^0 2 52 2 1 .5 frozen 1i tter N20E 60 3 52 0 2 porous concrete N2.0E 70 k 51 0.5 0.5 frozen 1i tter N20E 70 0.5 porous concrete 5 67 frozen - no other information ava i 1 able T ransect: PMT-2 Area: Pimentel Meadows Date: 1-28-1969 Elevation: 7500 Vegetation: Jeffrey pine and wh i te fir large sawt imber Point Snow Litter F rost Frost Type Aspect SI ope Depth Depth Depth (percent) ( in .) (in.) (in.) 1 k o 0.5 1 .5 porous concrete North 60 2 T 1 porous concrete North 60 3 50 0.5 2 porous concrete North 60 k 62 0.5 2 porous concrete N20E 60 5 60 0.5 2 porous concrete N50E 60 6 51 0.5 0 N50E 60 7 66 1 0 N30E 60 8 56 0.5 0 East 60 9 55 0.5 0 South 30 10 52 T 0 South 30 1 1 40 1 0 slow 30 12 57 0.5 0 S30E 30 18 4 Appendix 4. (Continued) T ransect: CTT-4 CTT-5 Area: Constantia Date: 2 - 4-1969 Elevation: 4600 Vegetat ion: CTT-4: Jeffrey pine and white f ir sa p lin gs, poles and sma11 sawt i mber CTT-5: Jeffrey pine poles and bitterbrush Point Snow Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) ( in .) (in.) CTT-4 1 2 0.5 3 porous concrete N40W 25 2 3 4 2.5 frozen 1i tter N65W 25 3 2 1 2 porous concrete N70W 25 4 0 0.5 2 porous concrete N60E 50 3 granu1ar 5 0 2 2 frozen 1i tter N70E 50 1 .5 granular 6 5 0.5 3 porous concrete N20W 50 7 2 2 2 frozen 1i tter N20W 50 8 5 2 2 frozen 1i tter N1 0W 50 9 3 1.5 1 .5 frozen 1i tter N10W 50 10 4.5 0.5 1 porous concrete North 50 CTT-5 1 0 4.5 2 frozen 1i tter S40E 20 2 2 T 2 porous concrete S40E 20 3 1 0.5 2 porous concrete S50E 20 4 2 0.5 2.5 porous concrete S50E 20 5 3 0.5 2 porous concrete S30E 20 185 Appendix A. (Continued) T ransect: DRT-3 Area: Deans Ridge Date: 2-9-1969 E1eva t i on : 5^00 Vegetation: sugar pine, Jeffrey pine, incense-cedar, and white fir saplings poles, small and large sawt imber Point Snow Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) (in.) (in.) 1 32 0 S70E 10 2 33 1 0 N80E 20 3 25 1.5 0 N65E A0 A 20 0.5 0 N60E 60 5 27 0 0 N80E 60 6 21 1 0 — • N80E 60 7 15 1.5 0 S80E 60 8 2A 0.5 0 ---- East 60 9 30 0.5 0 N80E A0 10 31 0 0 N60E A0 T ransect: DRT-A Area: Deans Ridge Date: 2-9-1969 E1evat ion: 5350 Vegetation: sugar pine, Jeffrey pine, incense-cedar, and white fir saplings poles, small and large sawt i mber Point Snow Litter Frost Frost Type Aspect Slope Depth Depth Depth (percent) ______(in.) (in.) (in.)______1 23 1 0 ------NAOE 10 2 21 1 0 N70E 10 3 28 1 0 S70E 10 A 27 0.5 0 S70E 10 5 2 A 0.5 0 S70E 10 186 Appendix 4. (Continued) Transect: PMT-3 Area: Pimentel Meadows Date: 3-4-1969 E1evat i on: 7500 Vegetat ion: Jeffrey pine and white fir large sawt i mber Point Snow Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) (in.) ( in .) 1 82 1 0 ------N30W 60 2 72 0.5 1 porous concrete N10W 60 3 60 1 0 ------N20W 60 4 72 0.5 0 ------N10W 60 5 70 0.5 0 ------North 60 6 69 0.5 0 ------North 60 7 72 0.5 0 ------N30E 60 8 74 0.5 0 ------N40E 60 9 79 0.5 0 ------N60E 60 10 74 0.5 0 ------S40E 30 11 72 1 0 ------S10E 30 T ransect: BCT-1 Area: Bootleg Canyon Date : 3-^-1969 Elevation: 6400 Vegetation: Jeffrey pine poles and small sawtimber Point Snow L i tter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percen t) (in.) (in.) ( in .) 1 40 1 0 N70E 10 2 34 3 1 .5 frozen litter N70E 10 3 60 0.5 1 porous concrete N70E 10 4 42 3 0.5 frozen 1i tter N70E 10 5 47 2 1 frozen 1i tter N70E 10 6 39 2 0 N70E 10 7 47 1 1 frozen 1i tter N70E 10 0.5 porous concrete 187 Appendix 4. (Continued) T ransect: CTT-6 CTT-7 Area: Constantia Date: 3-6-1969 E 1evat i on: 4600 Vegetation: CTT-6: Jeffrey pine and white fir sap 1i ngs , poles and sma11 sawtimber CTT-7: Jeffrey pine poles Point S now Litter Frost Frost Type Aspect S 1 ope Depth Depth Depth (percent) (in.) (in.) (in.) CTT-6 1 2 2.5 2.5 frozen 1 i tter N30W 30 2 T 2.5 1.5 frozen 1i tter N50W 30 3 1 2.5 1.5 frozen 1i tter N80W 20 4 1 0.5 0.5 frozen 1i tter N80E 50 1 porous concrete 5 T 0 1 .5 porous concrete N70E 50 6 0 0 3 porous concrete N70E 50 7 8 0.5 1.5 porous concrete North 50 8 2 2.5 1.5 frozen 1i tter N20W 50 9 2 1 1 frozen 1i tter N20W 50 1.5 porous concrete CTT-7 1 I 1 1 frozen litter S60E 20 2 0 0 0.5 porous concrete S40E 20 3 1.5 1.5 1 frozen 1 i tter S60E 20 4 2 0.5 1 porous concrete S50E 20 5 4 1 0 S50E 20 6 8 0 1 porous concrete S40E 20