APRIL,1911. MONTHLY WEATHER REVIEW. 609 CLIMATOLOGICAL DATA FOR APRIL, 1911. DISTRICT No. 11, CALIFORNIA. Prof. ALEXANDEBG. MCADIE,District Editor. GENERAL SUMMARY. Weather Bureau. The weather map of April 12 indi- cated a ra id rise in pressure with moderate to brisk April, 1911, was the coldest April since 1900, and with north win& during the ni ht of the 12th, followed by this exception the coldest since the tabulation of such heavy or killing frost,s on tie mornings of the 13th and records began in 1897, and it was also rather a dry montsli. 14th. The winds continued as expected, and in most Compared with April of last ear it was niuch colder, portions of the Sta.te the temperature did not fall so low but with a greater rainfall. Tiere was an average nip- as it would otherwise have done and was several de ees ber of rain da although these occurred mostly dunng higher than anticipated. In t.he San Joa uin Vsey, the first &caz: It is somewhat difficult to classify however, the wind lulled before sunrise of t% e 13th and the present April, as it belongs neither in the dry class the temperature fell in the vineyards as low as 27'. It nor yet in the wet class. Nor was it exactly a normal was not, however, of long duration. Under ordinary month, as it was too cloudy and too cold to be thus conditions the fall would not have been dangerous, but classified. The season as a whole has been a late one, the time was a critical one in the district under consid- and the month of April showed the influence of some eration, as the grape vines were in a tender condition. general cause operating over the entire Pacific slope and The first reports were to the effect that Mala a and seed- tending to retard the usual seasonal change from winter less vines were injured beyond recovery, an% would not conditions. There have been Aprils when rain fell on sprout again, but that the Muscats would niake a fairly more than half of the days of the month. Such was the good second crop. At the time of writing, however, it April of 1880. On the other hand, in April, 1857, little, would seem that the first estimates of damage were if any, rain fell and a similar condition occurred agaiu in entirely too large, and that the damage in general will 1909. Entirely unlike the April of last year, when the not exceed 10 per cent of the anticipated yreld. snow cover in the mountains was of less depth and mea Tree fruits were not materially injured. It was stated than had been known in 40 years, the present A ril was that throughout the Santa Clara Valley, ortions of the one of comparatively heavy snowfall, and at tf e close bay valleys, and part of the Sacramento $alley, a ricots of the period there was every prospect of an abundant and prunes suffered severely; but later reports f;o not supply of water for the summer months. This means confirm this view. The frost was neither severe enough much to the aFiculturists, the stockmen, and irrigation nor of sufficient duration to do the injury estimated. and power projects. The forecast can be safely made Pears were hardly out of bloom when the frost came and that the season will be a late one in the mountains so were protected by their jackets. Almonds, apricots, and far as travel is concerned, and that many of the-mountain prunes had passed their most critical st e and, more passes will not be open before the first week 111 July, if over, the minimum temperature in most orcY ards was not not later. below 32' at the level of the fruit. Garden truck and April 1910, was noticeable for its com arative dry- fruit near the ground were dama ed to some de ee. ness, whereas April, 1911, was distinctly (Yam g, cloudy, Tomatoes, otatoes, and berries in Pow places and w ere and cool. The highest temperature reache at any not covere(P were injured; but all high-ground vegetationT point in the State was 13' lower than the highest~ recorded escaped injury entirely. Ample warning of the condition during April, 1910. was given and in some places where protective methods No unusudv hkh winds occurred during: the month were resorted to the results were satisfactory. except on the"18th, when a maximum velocity of 84 One of the most interesting features connected with the miles from the northwest was recorded at Mount Tamal- frost condition was the estrenie dryness of the air in the ais, 75 miles at Point Reyes and 56 miles at Farallon interior valleys. It is not easy to explain the cause of fsland. These high velocities did not last long, and in the rapid drying of the air, as neither the season nor the that respect were unlike the steady and rolonged high general air movement warranted any unusual decrease northwest winds of May an-d June, so c Earacteristic of in humidity. ap roaching summer in thls section. TEMPERATURE. $he most important climatic occurrence during the month was the killing frost condition of April 12-13. The niean temperature for the State was nearly 2' Elsewhere will be found an article describing in some below the nornial, making the month, as above stated, one detail the effects of the frost in the San Joaquin Valley, of the coldest on record. The following table gives the and it will only be necessary here to refer briefly to the iiiean values for California during the time for which general conditions and the service rendered by the records have been kept. Unauthenticated | Downloaded 09/28/21 01:39 AM UTC 610 MONTHLY WEATHER REVIEW. APRIL, 1911 The following table gives the nieans and departures for EARTHQUAKES. each April from 1897 to 1911, inclusive: Earthquakes were re orted at Brawley, 26th, 28th; int Loma, 28th; at anta Clara, 6th, 11:49:36 p. m., Years. Mean. Depar-ture. Years. ‘ Meau. 8 I 1 I period 1 second, origin 110.7 kilometers southeast; loth, 10:51:15 a. m., period 1.5 seconds, .origin 190.7 kilo- OF. OF. OF. meters west, 30’ 58‘ N., small tremors all da 1887... .............. GO. 6 +4.5 1905 ................. Ism..... ............ w. 9 +4.8 1906 .................i 56.3 +0.2 10:26:84 p. m., period 6 seconds, origin 157 kiometers24thJ lsw.. ............... 58.1 +?.0 1907 ................. 58.2 I +?.1 a. 1800. ................ 53.9 -2.2 1908 ................. I 58.4 +2.3 east, 24O 21’ N., hght shock felt; 28th, 2:01:52 m., 1901 ................. 55.8 -0.3 1m. ................. +l. 5 period 1 second, origin 212.5 kilometers west, 42’ 16’ N., ISM.... ............. 56.2 fO. 1 1910 .................I E:! +3.i Irn.... ............. 54.8 -1.3 1911.. ............... I -1.9 second shock, 2:lO:Ol a. m., ended 2:11:30 a. m., many la................. 57.2 +l. 1 i %.-I small tremors during day. Berkeley: 19th, 12:20:19 p. m. Perceptible motion The hi hest tem erature reported at any station waa ended 12:23:05 p. m. The shock was ve feeble, but 97’ at Or7 eans on tg e 23d. This was 13’ lower than the was sharply marked on the seismogram. Pt originated highest recorded in April, 1910. The lowest temperature at a distance of about 24 miles south-southeast from at any station during April, 1911, was -2’ at Suniniit Berkeley. Magnified SO times the earth motion (double on the 12th, which was 11O colder than the lowest recorded amplitude) reac.hed a maximum value of 1.75 milli- during April, 1910. meters. The sec.ond shock, 4 trifle feebler than the first, occurred at 9:40:48 p. m. Origin about 25 miles south- PRECIPITATION. southeast. The third shock at 4:39:02 a. m. Direction The average monthly precipitation for the State was and distance of the origin could not be determined. 21st, 1.93 inches. m., feeble and no estimate of direction or distance The following table gives the average and departure can6m45 E e made. 35th, a near shock at 10:27:34 p. m., from the normal fl r each April from 1897 to 1911, with a magnification of SO times a mmimum earth shift of inclusive : 8.5 millimeters was registered in the north-south direction and 2.25 millimeters in the east-west direction. The in lay to the south at a distance of about lS0 miles. Y-. Mean. , 2:02:16 a. m., origin 1,700 miles from Berkeley; di- __ -- ~- -___ I- rection uncertain. The shock is feebly recorded here, in- Inches. Inches. Inches. Inches. dicating that it had no great strength at ori 1897... .............. 0.51 -1.61 1905. ................ 1.18 -0.94 1m................. .41 -1.71 1906. ................ 1.68 - .44 maximum earth shift registered was 1.5 1m................. .(10 -1.52 1907.. ............... 1.11 -1.01 1800.. ............... 2.14 + .m 1908.. ............... .G7 -1.45 magnification SO. 1801 ................. 2.16 + .M 1m................. .12 -2.00 EcZipse.-A artial eclipse of the sun was noted at San 1802 ................. 1. ss - .24 1910.. ............... .62 -1.50 1WN. ................ 1. ?8 - .M 1911.. ............... 1.93 - .19 Franclsco on tR e 28th, beginnin about 3.05 p. m. and 1904.. ............... 2.18 + .OB ending about 4.36 p. m. At #an Diego the observer states that the moon’s shadow caused an interruption of The greatest monthly rainfall was 8.65 inches, at Inskip.