Experts say Oregon is becoming less resilient to drought as fewer seasons of abundant rain and snow prevent it from bouncing back from hot and dry conditions.
The Capital Press reports that Larry O'Neill, state climatologist at Oregon State University, says the current drought is "historically significant," with about three-quarters of the state experiencing conditions considered "extreme" or "exceptional."
However, the state is actually in the fourth year of below-average precipitation, which has exacerbated the drought during “unprecedentedly” high temperatures this summer, O’Neill told the Oregon Water Resources Commission on Wednesday.
“We don’t recover from droughts as quickly as we did previously,” he said. “We seem to be in perpetual drought.”
Parched soils were insufficiently recharged with moisture over winter and spring, which has harmed vegetative growth, including crops and forage, said Ryan Andrews, a hydrologist at the Oregon Water Resources Department, which is overseen by the commission.
Reservoir and stream flow levels are below average across most of the state, reducing water available to irrigators, while ranchers have sold off livestock due to poor rangeland conditions, he said.
Fish die-offs followed the June heat wave in several important rivers basins, including the Willamette, Grande Ronde, John Day and along the North coast, Andrews said.
The state would need plentiful rain and snow during the autumn to begin emerging from the drought, but the long-term federal climate forecast doesn’t anticipate such a reversal, he said. “We’re anticipating conditions to persist, at least in the near term.”
Between March and July, the state received less rain than during any comparable period in nearly a century, O’Neill said. “The dry spring and summer is one of the main contributing factors to why this drought has become so severe.”
The area under “extreme” and “exceptional” drought ratings is the most extensive in Oregon since the start of the U.S. Drought Monitor more than 20 years ago, he said.
The most severe “exceptional” level of drought now seen across one-fourth of the state would normally be expected to occur every 20 to 50 years, O’Neill said.
However, droughts are judged by historical standards, so the concept of such “recurrence intervals” grows less valid as dry periods become more common, he said.
“It’s going to take some time to get used to the new normal we’re experiencing right now,” O’Neill said.