Observed and Projected ERC and 100 hr Fuel Moisture Graphs by PSA

ZONE 631:	COLUMBIA BASIN OF OREGON AND SOUTHEAST WASHINGTON (WFO Pendleton)

This area is characterized as flat or smooth rolling hills in the Lower Columbia Basin of Northeast Oregon and Southeast Washington. Elevations range from about 200 ft MSL to approximately 3000 ft MSL along the foothills of the Blue Mountains. The weather in this area is characterized as warm to hot and dry during the summer with little precipitation, especially July through September. This is one of the two driest zones in the district. Precipitation averages range from 5-8 inches at the lowest elevations of the basin to near 20 inches along the foothills of the Blue mountains. The Cascade Mountains to the west and the Blue Mountains to the east have a considerable influence on this area. A rain shadow is often created from weather systems that move inland from the Pacific. Down slope foehn type winds are not uncommon during the fire season. The Columbia River Gorge frequently causes strong channeling of westerly winds into the area after a cold front passage, but with little rainfall. Gusts 20-25 mph are common on ridge tops. Occasional summer thunderstorms bring localized heavy rain, however average precipitation July through September is about .50 inches. This zone has a low frequency of lightning with around 5 thunderstorm days west of Arlington and 5-10 thunderstorm days east of Arlington. Agencies responsible for fire protection in this area are ODF Pendleton, ODF The Dalles, Prineville BLM, Spokane BLM, Vale BLM, and southeast DNR.