EXPERIMENTAL RESULTS 



Preoi-pitation and snowpaok. — In the upper reaches of the Experimental Forest, wind 

 reduces the efficiency of precipitation (shielded) gages. This effect results in reduced 

 totals, especially in the openings on the south (windward) aspect. Therefore, it is 

 assumed that the catch in the small openings on the north (leeward) aspect come nearer 

 to representing the "true" precipitation. At these sites, seasonal precipitation ranges 

 from 20 to 26 inches (table 3) . The amounts were above average at this elevation during 

 the 1968-1969 season and near average during the 1967-1968 and 1969-1970 seasons. 



The gages at the forest and small opening sites may register different phases and 

 amounts of precipitation during and after individual storms for reasons not related to 

 the wind factor. For instance, if the trees at the beginning of a storm are bare or 

 nearly bare of snow and the storm is comprised of snow, the gage in the small opening 

 will indicate a much greater catch by a wide margin than the gage in the forest because 

 the overhead canopies are loading and temporarily detaining the snowfall. On the other 

 hand, if it rains when the canopies are snow- loaded from a previous storm, the gage in 

 the forest will invariably show a greater catch than the gage in the small opening 

 because of the addition of sliding snow and drip from the canopy. Occasionally, during 

 storm-free periods, sliding snow and drip will be measured in the gage beneath the 

 canopy; of course, nothing will register in the gage in the small opening (see the 

 precipitation column for February 7-9 in table 2). 



Rainfall is interspersed with snowfall during early November which is the period 

 of transition. By December the annual snowpack begins to accumulate, although rainstorms 

 occur infrequently after that time. At the end of the winter season, total rainfall 

 may amount to several inches (table 3). On the north aspect, the snowpack usually 

 attains maximum depth in late March. On the south aspect, the start of the ablation 

 period may occur 40 to 55 days earlier. As expected, the greatest depth of snow 

 (table 3) is in the small openings. 



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