410 • TRANSACTIONS OF THE 



Territory. Gales are very strong from the southeasterly at Cape Men- 

 docino, and at the mouth of the Columbia River, north of which they 

 come more from the south. The temperature is usually high, and at 

 times of steep gradients, from Nevada southward; near Los Angeles the 

 warm " Santa Ana" winds may occur. Plate III serves to illustrate this 

 type, if the pressure over Idaho and Nevada is considered about 30.30, 

 and the low on the North Pacific Coast about 29.80 inches. 



North Pacific Anti-Cyclonic Type. 



This type is very frequent, but sometimes of short duration. It pre- 

 vailed from November tenth to fifteenth, December seventh to thirteenth, 

 December thirty-first to January tenth, February twelfth to twenty-first, 

 February twenty-third to twenty-fifth, March tenth to twelfth, March 

 twenty-third to twenty-eighth, April second to fifth, and April seventeenth 

 to twenty-ninth. While this type is prevalent, the high, as is implied by 

 its name, rests over Oregon and Washington Territory, with a permanent 

 low over Southern California. It is attended with clear weather, only 

 interrupted by an occasional shower near Vancouver Island. During its 

 prevalence in its perfection and greatest intensity, and while the isobars 

 are perpendicular to the coast line, is the time when the dreaded desiccat- 

 ing " north wind " prevails in the Sacramento and San Joaquin Valleys. 

 The temperature is high during the day, especially after several days' con- 

 tinuance of the type, while at night frosts often occur. The winds are 

 usually light and variable on the coasts of Washington Territory and Ore- 

 gon, but on the coast of California high with southerly gales. If in the 

 Spring during the prevalence of this type, high winds and sand storms 

 occur in Southern California, they are almost sure to be followed by rain. 

 The proverb that a succession of frosts is liable to be followed by rainy 

 weather, obtains warrant from the fact that the breaking up of this type 

 is usually foretold by frosts, and most certainly followed by rain. The 

 occurrence of this type on the first ten days of January, 1886, appears to 

 bear a certain relation to the great surges of high pressure from the Arctic 

 regions, moving well westward over British Columbia. The isobar of 30.3 

 to 30.5 inches inclosed the area. The weather on the coast was unusually 

 cool and clear, frosts extended into Southern California. During this 

 period remarkably cold weather was prevailing in the Eastern States. 

 These surges of high pressure, in their movement covering almost the 

 width of the continent during the first ten days of January, caused the 

 development of intense cyclonic areas, originating in the Gulf of Mexico 

 or Texas, and moving northeastward along the Atlantic Coast, accompa- 

 nied by the most severe cold wave of the year east of the Rocky Moun- 

 tains. Plate II illustrates this type. 



The General Cyclonic Type. 



This type is characterized by the most severe storms that occur on this 

 coast. The rain area overspreads all sections, falling in torrents, and gales 

 of the greatest violence with frequent thunder storms occur, rivers over- 

 flow, and washouts impede travel. The barometer drops very low and 

 suffers rapid fluctuations, and remarkable gradients occur between the 

 coast and interior. Simultaneous with this type is a series of exceedingly 

 high pressure waves over the Rocky Mountain plateau and States to the 

 eastward, accompanied by severe storms and intense cold. During the last 

 season there were only two occurrences of this type, viz., from November 



