48 JOIRXAI, OF 1*()KI':STRV 



studies on three separate areas — in central Oregon, in soutliern Wash- 

 ington, and in central Washington. Messrs. Sproat, Kraebel, Kloe, 

 Ramsdcll, Ilellen, and (iritifin took the observations and A. .\. Grififin 

 compiled the data. On each area the depth, density, and distril)ntion 

 of the snow throughout the melting season at from 8 to 20 typical 

 ojjservation points or stations were observed during the seasons 1916 

 and 1917. These stations were well distributed, altitudinally. from a 

 minimum of 1,200 feet to a maximum of 6,800 feet. The forests con- 

 sisted largely of Douglas fir, hemlock, true firs, and western pines, and 

 the density of the stand, although somewhat variable, ranged between 

 0.45 to 0.8. The three areas were located upon important tributaries 

 of the Columbia River, and each watershed was important and valuable 

 on account of the irrigation water which it furnished. The stations 

 were located in the open and in the forest in pairs, being similar in all 

 respects except forest cover. Careful notes were taken, especially 

 upon aspect, degree of slope, and distance to trees, stumps, edge of 

 timber, and upon the possibilities of drifting. Snow depths were 

 measured at regular intervals of a week or less, from the period of 

 greatest depth, throughout the melting season. The season varied 

 from 9 to 17 wrecks. Permanent graduated stakes were used. Snow 

 density or water equivalent was measured at each regular observation 

 by means of standard U. S. Weather Bureau apparatus and by means 

 of sampling cans. 



The results of the observations show very clearly that there was 

 more snow in the open than in the forest when the observations began 

 (in early April), but that in spite of this there was still considerable 

 snow left in the forest after the snow had disappeared from all the 

 open stations (in July). Thus, on the Tumalo area, in central Oregon, 

 no snow was left on July 18, 1916, on any of the stations in the open, 

 while the forest stations showed an average of 19.3 inches of snow, 

 equivalent to 8.7 surface inches of water. On the Wind River area, 

 in southern Washington, 28.2 inches of snow remained at the forested 

 stations as the corresponding open stations became bare. On the 

 Yakima area, in central Washington, 19 inches remained after the cor- 

 responding open stations became bare. Thus, on the average, the 

 forest areas conserved 7.5 surface inches of water through a period 

 of from 17 to 42 days — a factor which is of vital importance from an 

 irrigation viewpoint. 



The influence of forests upon the melting of snow was correlated 

 with site factors; but, due to insufficient data, most of the relations 



