CLIMATIC FACTORS : THE AIR 



93 



from snow. To be sure, where snowfall comprises a high per- 

 centage of the total precipitation, it must be of relatively greater 

 importance than elsewhere. Subalpine forests are often almost 

 completely dependent upon soil water derived from snow. The 

 red fir forest along the crest of the Sierra Nevada receives prac- 

 tically no rain throughout the growing season. However, the 

 cool summer days at these high altitudes do not create high water 

 losses, and since snow falls of sixty feet have been recorded here, 

 the resulting water is adequate to maintain the forest and to pro- 

 vide, as it runs off, an excess usable for agriculture at lower alti- 

 tudes. 



FlG. 40. A standard rain gauge and measuring stick. Cutaway view to 

 show funnel and inner tube.— Courtesy Friez Instrument Division, Bendix 

 Aviation Corporation 



