Climatological data for the States falling within the area of 

 interest were obtained from the National Oceanic and Atmos- 

 pheric Administration, National Climatic Center, Ashville, 

 N.C. Monthly precipitation and temperature records were ex- 

 amined for October through April 1976-77. The monthly actual 

 and percentage of normal climatic divisional average precipita- 

 tion was computed for each State. Only those divisions that tell 

 within the survey limits were used to obtain the average for 

 each State. The average monthly means and degrees (°Faren- 

 heit) temperature departures from normal were computed for 

 each State for the same climatic division as for precipitation. 

 Precipitation and temperature normals were based on the 

 1941-70 record. Precipitation in areas of little or no reported 

 winter injury was compared with that of those where the most 

 extensive injury was reported. This was done by matching 

 management areas with climatic divisions and selecting those 

 that corresponded most closely. Other factors considered were 



elevation (that is, mountains, valleys, plateaus) and distribution 

 of shrubs, particularly big sagebrush. 



RESULTS 



Description of Winter Injury 



In the areas of sagebrush injury we visited in south-central 

 and southern Idaho and northern Utah, damage occurred pri- 

 marily above 6,000 ft ( 1 800 m). This was generally true with 

 survey reports, although in California and Oregon the elevation 

 was somewhat lower. Typically the most severe damage oc- 

 curred in mountain valleys (cover photo) and other areas of 

 normally deep snow cover (fig. 2). Southwesterly exposures and 

 windswept ridges were usually free of injury. Virtually all large 

 plants of mountain big sagebrush were killed on the high 

 plateau areas we surveyed on Idaho's Sawtooth National Forest 

 and Utah's Uinta and Manti-LaSal National Forests (fig. 3). 



Figure 2.— A depressed area on the lee of a 

 glacial morain with winter-killed mountain big 

 sagebrush. North of Borah Peak, Lost River 

 Range in Idaho. 



Figure 3.— Extensive sagebrush winter-kill on 

 the high Cassia Plateau of southern Idaho, 

 Sawtooth National Forest. 



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