Drought conditions are spreading in Oregon and Washington, and an El Nino forming in the Pacific Ocean will tilt the odds in favor of more warm and dry months ahead, federal officials reported.
The percentage of Oregon in moderate or severe drought was up to 80 percent from 68 percent from the week before, according to the U.S. Drought Monitor. Meanwhile, a moderate drought in Washington expanded to 26 percent from 17 percent of the state.
Conditions in Idaho and California were unchanged, with 6 percent of Idaho and 44 percent of California in some degree of drought. The Drought Monitor has four stages of drought, ranging from moderate to exceptional.
Also the National Weather Service’s Climate Prediction Center reported that the odds favor above-average temperatures in the four states during August, September and October.
Looking further ahead, the center puts the chances that an El Nino will form in the Pacific Ocean by November at 70 percent. An El Nino, a warming of equatorial sea-surface temperatures, usually leads to warmer and drier winters in the Pacific Northwest.
Forecasts of an El Nino have missed the mark before. A large amount of warm water below the surface makes forecasters slightly more confident this time, according to the center.
Drought conditions in Oregon are most severe east of the Cascades, where 25 percent of the state has fallen into a “severe” drought, the level above “moderate.”
In Washington, the moderate drought conditions are mostly west of the mountains, though drought conditions extend up the Columbia Gorge as far east as Benton County.
River flows in southwest Washington are particularly low, resembling levels during the 2015 drought, according to Ecology. The department last month curtailed the water-rights of 93 irrigators in the Chehalis basin.
East of the Cascades, the water-rights of about 40 irrigators in the Walla Walla basin in southeast Washington have been curtailed.
Ecology has warned 65 irrigators in the Methow basin and 25 along the Similkammen River in Okanogan County they may have their water rights restricted because of low flows.
The Bureau of Reclamation projected this month that junior water-right holders in the Yakima Valley will receive 100 percent of their water supplies for the irrigation season.