stations show a fairly consistent relationship from year to year. All-station outflow 

 was roughly the highest during 1967-1968, intermediate during 1968-1969, and lowest 

 during 1969-1970. A complete tabulation of seasonal outflows is presented for each 

 year, by study, in table 3. 



By comparing the lysimeter outflow with precipitation observed during all 3 years 

 at station 39, we find that 63 percent of the precipitation observed during 1967-1968 

 had drained from the snowpack by April 1; during 1968-1969 the release by April 1 was 29 

 percent; and during 1969-1970 the release was only 19 percent prior to the spring season. 



Souraes of water released from snowpack .- -Exce^gt for a few of the months of study, 

 throughfall-drip percolate in the forest exceeded rain percolate in the small opening. 

 Throughfall-drip percolate reached significant proportions during brief periods of 

 general thaw from December through March. Four weather events in the interval of 

 December 1969 to January 1970 are cited as typical examples of water being released at 

 moderately high rates in the forest and small openings. The individual events plot as 

 rather sharp inflections on the six accumulation curves in figure 5. The extended rises 

 on the three curves for the forested stations include additional water that apparently 

 resulted from melting snow suspended in the trees. (The suspended snow had accumulated 

 in the canopies prior to each general thaw.) All four events in this example are 

 associated with rainfall and a warming trend. In fact, much of the throughfall-drip 

 percolate originates as rain filtering through suspended snow melting in the canopy. 

 At the end of two of the four events, the canopies were completely bare of snow. 



Figure 5. — Accumulated release 

 of water from snowpack for 

 representative period^ 

 December 1969-January 1970, 

 at small opening stations 

 S0[Z9], S0[45], and S0[49], 

 and forest stations F[40]j 

 F[42]j and F[47]. Number 

 at end of curve represents 

 total release of water in 

 inches for 2-month period. 



6.5 

 6.0 

 5.5 

 5.0 



- 4.5 

 c 



- 4.0 

 I- 



z 



< 3.5 



LEGEND: 



FOREST 



SMALL OPENING 



10 15 20 

 DECEMBER 1969 



30 



15 20 25 

 JANUARY 1970 



10 



