The National Drought Mitigation Center updates their Drought Monitor every Thursday, outlining the geographic details of drought conditions throughout North America. In today’s update, the extreme drought category was expanded to include much of Eastern Washington from the Tri-Cities northeast toward the Spokane area. Previously, only small sections near Prosser and Waitsburg were seeing extreme drought. This is part of the larger drought plaguing the western United States.
Droughts are classified on the following five category system based on rainfall patterns, temperatures, soil moisture, and other parameters:
The Tri-Cities and much of Central Washington have been in some form of drought since mid January 2020. During Summer 2020, extreme drought spread into Central Washington (generally along US 97), but modest improvement was made thanks to a few heavy snow storms during the winter. Still, that lowland snow was not enough to refill the water coffers and drought conditions are once again worsening. The drought is now more widespread within Washington than last year.
This year, the Tri-Cities experienced its third driest Spring on record and so far not even an inch and a half of water-equivalent precipitation has fallen. The Columbia Basin is dry, of course, but the average year-to-date value is closer to four inches. It is true that the region saw quite a bit of snow in February. A good average snow to liquid water ratio is 10:1, meaning that ten inches of snow is equivalent to one inch of rain. That ratio varies from wet snow at about 6:1 to dry and cold snow which can exceed 30:1. With how dry the Tri-Cities is, our ratio is often above the 10:1 number, meaning that while we got nearly a foot of snow in February it had an unimpressive water content.
Extreme drought extends south through Central Oregon and into California. Between Bend and Klamath Falls, exceptional drought is occurring. Drought relief throughout the American West is not expected through the summer according to the Climate Prediction Center. In fact, with the exception of the Olympic Mountains, long-range forecasts call for the rest of the west to come into drought. This includes nearly all of Western Washington and large sections of Idaho, Montana, and Wyoming.
In unirrigated farmland the impacts of this drought have been being felt for a while. A farmer in Walla Walla County reported in early June that instead of the typical 90-120 bales of hay they typically get from their land, they got none and that they have no forage. Around the same time, NPR reported that wheat farmers in the Horse Heaven Hills are experiencing widespread empty wheat heads. Historically, extreme droughts in Washington have also caused wells to run dry and a decrease in hydropower generation.
For areas of Washington that benefit from irrigation, especially from the Columbia and rivers draining the Cascades, healthy snow in the Washington Cascades and little drought in British Columbia are helping to mitigate impacts from the drought. Drought has not yet spread into these mountain areas, though it is likely to dry out during the summer months. The Oregon Cascades are not preforming as well. To the south of the Three Sisters, the mountains have severe to extreme drought while to the north there is moderate drought.
Beyond agriculture, widespread dry conditions in the Western United States set the stage for large fires. In their monthly outlook, the National Interagency Fire Center gives an above normal risk for significant wildfires in the Columbia Basin, Oregon Cascades, and on the Palouse for June. This risk spreads to include all of Eastern Washington, Western Oregon, the Washington Cascades, and Idaho for July through September.
The featured image for this blog post is the Washington drought monitor valid June 8, 2021 from the National Drought Mitigation Center.
