CLIMATIC CONDITIONS 



On the average, the study area receives about 14 inches of precipitation 

 annually. However, precipitation varies greatly between years and between sites 

 near the study area (Prodgers 1978). Because convective storms, rather than 

 cyclonic storms, often account for much of the spring-summer precipitation, 

 neither records at Circle (23 kilometers southeast of the study area) nor Fcrt 

 Peck (60 kilometers north-northwest of the study area) accurately represent 

 precipitation at the study area. Plans to establish meteorological stations at 

 the study area have not materialized. 



In 1977, which was a very dry year, some exclosures suffered from heavy 

 grasshopper infestation. The winter of 1977-78 was severe and resulted in 

 above-average snowfall. The spring and summer of 1978 were extremely wet and 

 were followed by another winter of heavy snowfall. These conditions ameliorated 

 the effects of the rather dry year of 1979. The winter of 1979-80 was quite 

 dry, and by summer 1980, the area was in a severe drought. The study area 

 sustained very little grasshopper damage in 1978, 1979, and 1980. 



The study area received an estimated 1.5 inches of precipitation from 

 January through July 1980. In early August, about 1.5 inches of rain fell. 

 Vegetation was still responding to this precipitation at the time of clipping. 

 Once again. Circle precipitation records failed to reflect conditions in the 

 study area. At Circle, May-June precipitation was 2.35 inches, while April-July 

 precipitation was 4.15 inches. Such differences in rainfall illustrate the need 

 for on-site monitoring of the water balance. 



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