60 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



the prompt rendition of reports, are fully appreciated, and effort 

 has been made to attain the highest possible degree of accuracy in 

 these respects. To best accomplish this, however, it is imperative 

 that a more frequent inspection of these stations be provided for. 

 A personal visit to the observer enables the section dn^ector to ac- 

 quaint himself with the general environment of the station, to 

 remedy defects in the exposure of instruments, where such exist, 

 or in the manner of recording the observations, and also encourages 

 the observer to renewed efforts if he has become discouraged at an 

 apparent lack of interest in the work. It is also believed that in 

 the estabhshment of new cooperative stations the equipment should 

 be installed and the observer instructed whenever possible under 

 the personal supervision of a trained Weather Bureau official. 



SNOWFALL AT HIGH ALTITUDES IN WESTERN STATES. 



The Weather Bureau for some years past has sought to determine 

 in the spring of each year the probable amount of water contained in 

 the snow cover of the higher levels that may later be available for 

 irrigation and other purposes. 



The project is a difficult one because of the fact that, as a rule, the 

 higher altitudes are either not inhabited, or, in many cases, only 

 during the summer months; hence, with the exception of the low 

 passes occupied by the continental trunk lines of railroad and a few 

 isolated points where mining camps are located, comparatively little 

 is known of the total amount of the winter snowfall. The total num- 

 ber of high-altitude snowfall stations is gradually becoming less and 

 less, due to the abandonment of mining camps and other enterprises 

 that have been hitherto maintained throughout the year at high alti- 

 tudes. The present method of obtaining observations of the winter's 

 snowfall through persons who may reside on the higher altitudes 

 throughout the year has reached the limit of its development. On 

 the other hand, the plan of intensive surveys in small watersheds, as 

 developed originally by Thiessen, promises relatively valuable 

 results, but of extremely local application. Three such surveys were 

 made during the current year, as follows: One in City Creek water- 

 shed, near Salt Lake City, Utah, at elevations ranging from 8,500 to 

 9,500 feet above mean sea level; a second in the watershed of Cotton- 

 wood Creek, a tributary of Boise River, that joins the main river a 

 short distance above Arrowrock Dam; and the third by the Rock 

 Creek Conservation Co., in cooperation with the Weather Bureau, in 

 the watershed of Sand Lake, Carbon County, Wyo., at altitudes of 

 between 10,000 and 10,500 feet above mean sea level. 



All of these surveys were conducted in fairly accessible regions, the 

 plan being to pack supplies, implements, and tent equipage to some 

 convenient base, go into camp at that point, and make daily journeys 

 thence into the snow fields. The greatest objection to this plan is the 

 time consumed daily in going to and returning from the snow fields. 

 Where it is possible to transport supplies and material into the heart 

 of the snow fields, as was done in the City Creek project, much advan- 

 tage is secured. 



The survey in the watershed of City Creek, in 1915, whence Salt Lake 

 City draws its water supply, showed 30 per cent less water in the 

 snow cover than in the previous year, and also that the snow was in 

 a condition favorable to early melting. 



