The drought gripping the Western United States continues to worsen in Eastern Washington. In this week’s update of the U.S. Drought Monitor, exceptional drought (level 4/4) was noted as stretching from the northern end of Rattlesnake Mountain to Sprague Lake, which lies between Ritzville and Spokane. A small sliver of exceptional drought conditions also reaches in from Idaho to include Clarkston. This is the first time since the U.S. Drought Monitor came into being in 2000 that exceptional drought has been observed in the state.
While the U.S. Drought Monitor only extends back about twenty years, we can use other metrics to see how this year’s drought compares to those that came before 2000. At Ritzville, 2.75 inches of precipitation have been observed so far this year. This is the lowest year-to-date value recorded there since records began in 1905 and is well below the average year-to-date value of about eight inches. Other locations throughout the Columbia Basin are seeing similar readings.
The worsening this week is the result of above average temperatures that have continued since the Great Northwest Heatwave that started toward the end of June. This, plus the lack of rainfall, helped to accelerate the drying out of soils that weren’t already parched. With this being the first time exceptional drought has been noted in Washington, the National Drought Mitigation Center does not list anything in their historically observed impacts section for the state. We can, however, get an idea of things to expect from what California has observed in the past when experiencing this low of water supply. Many of these impacts are likely unsurprising and include the following:
- A bad fire season with extensive areas burned
- Impacts to recreation
- Wetlands dry up
- Wildlife death is widespread
- Poorer air quality
No improvement is currently forecast with the Climate Prediction Center favoring below average precipitation for the Pacific Northwest through at least the beginning of August. In fact, it seems likely that the exceptional drought region will spread to include other parts of Eastern Washington over the next month or so. Elsewhere throughout the state, most of Eastern Washington remains in the extreme drought (level 3/4) category. West of the Cascades, Vancouver is seeing severe drought (level 2/4), but moderate drought (level 1/4) has now spread to include the I-5 corridor south of Tacoma, portions of the Olympic Peninsula, and the Bellingham area. Abnormally dry conditions are now being noted throughout the rest of the state.
Most of the Washington Cascades are not yet in a drought (though they are now listed as abnormally dry) and the drought is not quite as bad in southern British Columbia. These are some main source regions for the water used for irrigation in the Columbia Basin. Their current status is healthier than in the basin itself, which will help mitigate some drought impacts to agricultural interests who are able to irrigate.
The U.S. Drought Monitor is released each Thursday and is based on conditions on and leading up to that week’s Tuesday. It is created by the National Drought Mitigation Center in Lincoln, Nebraska. You can keep up to date on precipitation and other forecasts for the Pacific Northwest by using the Forecast Map tool on my website.
