MONTHLY WEATHER REVIEW Editor, ALFRED J
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MONTHLY WEATHER REVIEW Editor, ALFRED J. HENRY ~ ____~~~~ ~ . ~ __ VOL. 58,No. 3 1930 CLOSEDMAY 3, 1930 W. B. No. 1012 MARCH, ISSUED MAY31, 1930 ____ THE CLIMATES OF ALASKA By EDITHM. FITTON [C‘lark University School of Geography] CONTENTS for Sitka, the Russian capital. Other nations, chiefly Introduction_____---_---------------------------------. the English and Americans, early sent ships of espIoration I. Factirs controlling Alaskan climates- - - - - -.-. - :g into Alaskan waters, and there are ecatt.ered meteoro- 11. Climatic elements- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ST logical records available for various points where these Sunshine, cloudiness, and fog-- -_--__-----__--- 87 vessels winte,red along Alaskan shores (7, P. 137). Temperature- - - - - __ _____ - - - - - - - - - _____ - _____ 59 Alter the United States purchased Alaska, the United Length of frostless season.. - - - - - - - - - __ - - - - -.- - - States Army surgeons kept weather records in connection Winds and pressure _____._____________________:: January and July _-___-----.--________________91 with the post hospitals. “In 1878 and 1579, soon after Precipitation - - - -.- - - - - - - - - - - - - - - - - - - - - - - - - - - 93 the orga,nization of the United Stat,e,s Weather Bureau, SnowfaU_____________________~_________-_____96 first under the Signal Corps of t’heArmy, later as a’bureau Days with precipitatioil- - - - - - - - - - - - - - - - - - - - - - - 111. Seasonal conditions in the cliniatic provinces-_ - - - - 9”; of the nePartlne11t of &Ticulture, a feltrfirst-class observ- I A. Pacific coast and islsnds (marine) - - - - -_- - - - 98 ing stations, together mth several volunt,ary stations of I B. Pacific coast and islands (rain shadow)------ 99 lamer order, were established in Masl<a” (1, p, 133). 11. Bering Sea coast and islands (semi-ice marine) - 99 1917 appropriationof $l~,~~operlilit,ted the estab- 111. Arctic coast (ice-marine) - - - - - - - - - - - - - __ - - - an IV. Interior (cold cont,inent,al) __ - - - __ - - - lishment of additional first-class observing sta.tions in Bibliography ___----___---__--________________102 Alaska (39, p. 464), SO that there are now 9 such stat,ions, while 44 cooperative observers bring the total .up t,o 53 INTRODUCTION weather stations. The cooperative observers include United States experiment stations, radio stations, mining Popular opillion once pictured all Ahska as a frozen, and railway companies, and religiolls missions as well 8s treeless waste, inhabited only by polar bears and Eskimos, individuals. the latter living the year round in Snow igloos and sub- The present study is an attempt to bring up to date the sisting on seal meat. That such a description is more or climatic dat,a available for ~l~~k~.clevelancl Abbe, jr., less applicable to the tundra areas of the Bering and publishilig in 1906 a section on climate in Alaska as part Arctic coasts can not be denied, but Alaska is t,oo varied of professioIlal pape,rN~. 45, u. s. G. s. (1, 1341, in relief, climate, and resources to be pigeonholed wit’h a summarized the rec,ords used in his report as follows: phrase. In complete contrast with the flat, treeless tundra is t,he bold, fiorded coast of the ‘‘Panhandle ” The observations made up to the end of 1877 have already been summarized by Ddl and Baker, and published. t.ogether with a very wliose scenic beauties of glacier and forested nlountain full bibliography, by the Coast and Geodetic Survey. The results side, coupled with COO1 SUlnner temPeratUres, have nlade of observations made at six United States Army posts, froin 1861 of it a slimmer goal for anincreasing number of tourists to 1871, and the continuous series of RuRsian arid American each year. In contrast again is the broad interior plateau observations at Sitka, from 1847 to 1874, have been suniinarized by c. A. Schott, nud published ill two VOlUlneS by t,he Smit,hsonian region, drained by the lllightY Yukon, where lollg hours Institution. They form valuable suppleme~itsto the earlier mono- of sunshine bring SUIIlmer te;InperatUreS high enO1lgh for graph by ~~u and B&er. * * * ~1,~lllaterial fillmlliarized grains and vegetables to ripen and where berries are in the accompanying tableu was taken from the manuscript records produced in abundance. Still further contrast is ofisred covering the period froin 1868 to the present time, in the custody of the United States Weather Bureau. * * * These records by the lnajestic mountain ranges which flank ~l~~k~to were made by observers who may be grouped in four classes- north and south, the Alaska Range having the hig11est post surgeons at regular United States Army posts, regular Signal peak in all North Anierica-Mount McKinley. Truly Service or Weather Bureau observers, voluntary observers supplied Alaska does not warrant a blanket description of any sort. by the Weather Bureau Rith instruments, and members of various Many people have been attracted to Alaska-esplorers, espeditions. prospectors, * settlers, and tourists. Its resources of In 1925, Melvin B. Summers, Alaska section director gold and copper, seal:, salmon,.and scenery are the main of the United States Weather Bureau at Juneau, published support of the mhabitants, which according to the. 1920 a Summary of the Cliniat’ological Data for Ahska, by census numbered 55,061. Sections inc,orporating dat’a from the e.stablishnient of Of primary interest to prospective Alaskan travelers the stations t>hrough 1921 (29). The present, study and settlers are climatic conditions. The two nations makes use of these and other sources, as well as Climato- that have controlled Alaska have always been interested logical Data for Alaska, both monthly and annual pub- in its climate, because, being on the borderland for lications (37), and some manuscxipt data supplied by the human habitation, the extremes that would have to be Weather Bureau. endured there were of special concern. Before 1867, Although t’he data are pract’ically comple,t,e through when the United States purchased Alaska, Russian mis- 1927, a survey reveals t.he fact tha.t’only 29 stations have sionaries to the Eskimos kept weather observations at adequate records fiveraging over 10 years and covering their various posts and Government officials kept records (besides rainfall and temperature) wind direction, frost 111758-30-1 85 86 MONTHLY WEATHER REVIEW MARCH,1930 period, days with rain, snowfall, clouds, and so forth. The continuation of the North American Coast Ranges Even these data are not for the same series of years in in Alaska and the Alaska Range bear the chief responsi- many cases, but in spite of the seeming inadequacy of the bility for this contrast in climat,e between the Pacific records they are much fuller than those available when coast and the interior. The Alaska Range attaina heights former studies were made for they cover a longer and of over 20,000 feet and the whole of southeastern Alaska more nearly consecutive period of years. is backed by ra.nges of between 5,000 and 10,UOO feet. Such high inount,ains eflectively interrupt t.ho surface I. FACTORSCONTROLLING ALASKAN CLIMATES atmospheric circulation; hence in Alaska, they cut off the The title of this paper, The Climates of Alaska is used iiit,erior from the winds off the Pacific, thereby concen- advisedly for Alaska, has no climatological homogeneity. trat,ing prec.ipitation on the coast and decreasing it in the Regions adjacent on the niap are found to have widely interior; at the same hie they prevent t'he oceanic winds different climatic charac,teristics and it is the study of from moderating the temperatures of the interior and these striking contrasts and the reasons for them that hinder the passage of winter cold wind3 from the interior lend the major int,erest to Alaskan climatology. to the coast. The climatic. provinces into which Alaska has been Back of the Coast and Alaska Ranges is a rurd divided and the location of the climatological stations plateau region of 1,000 to 2,000 feet elevation, stretc mg therein are shown in Figure 1. northward t,o the Brooks Range. This range was crossed The Pacific coast and islands region is marked by heavy several times by Wilkins (42, p. 530) in his air flights from rainfsll, the rest of Alaska by little; the Pacific coast rain- Fairbanks to his base at Point Barrow preparatory to his fall has a cold season maximum, the precipitation over exploratory trip that culminated in hi3 fanlous flight from the rest of Alaska has a summer maximum; the Pacific Alaska to Svalbard (Spitsbergen). He found the moun- coast is equable, the interior est'renie, in temperature tains to be approximately 10,000 fe,et high, or about 5,000 characteristics. It is evident then that Alaska presents feet higher than was previously supposed. They, as well a marine climate along its Pacific border and a conti- as the Alaska Range,. play their part in keeping oceanic nental climate over the rest of its area. influences out of the mterior, and consequently the wide MARCH,1930 MONTHLY WEATHER REVIEW 87 Yukon Valley has the coldest and hottest temperatures is brought out that in no month does Boston’s percentage in all Alaska and only a meager precipitation. of possible hours of sunshine received reach as low a fig- Beyond the Brooks Range a coastal plain about 50 ure as the highest for Juneau. Nor does Juneau, even miles in width slopes to t’he Arctic Ocean. The interior in the long days of summer yhen ita possible hours of plateau slopes from its elevation of 5,000 feet just over sunshine are 17 or 18 a day, ever equal Boston in actual tho Canadian boundary gradually westward and finally hours of sunshine month by month. Boston has a disappears under the Bering Sea; the Coast Ranges also yearly total almost twice that of Juneau, though both gradually decrease in height to the westward but maintain places have, of course, practically the same yearly amount their identity far out into the ocean as the volcanic chain of possible sunshine.