MLRA 43 - Northern Rocky Mountains Idaho, Montana, Oregon, Washington, and Wyoming 282,650 km2 (109,130 mi2)

Climate:
Average annual precipitation--Mainly 625 to 1,525 mm, increasing with elevation, but almost 375 mm in the western part of the area and almost 2,550 mm in high mountains. Most of the precipitation during fall, winter, and spring is snow. Summers are dry. Average annual temperature 2 to 7 C in most of the area, but it is 8 C or more at low elevations. Average freeze-free period--45 to 120 days, decreasing with elevation, and as long as 140 days in low valleys of Washington. Frost occurs every month of the year on high mountains; some peaks have a continuous cover of snow and ice.

12/16/98