Early forecasting shows above-normal potential for large, costly fires west of the Cascades through spring into early summer, according to officials at the National Interagency Fire Center.
The Boise fire management office’s latest four-month forecast says there’s an above-normal potential for larger fires in Western Washington and Northwest Oregon this month and in May. The area for potential large fires is forecast to grow to include Northeast Washington in June, then, in July, all of Western Oregon.
The forecast shows even odds for big fires for much of the Northwest into early summer. The forecast does not extend into August and September, often the peak of the Northwest fire season.
John Saltenberger, a meteorologist at the Northwest Interagency Coordination Center in Portland, said significant fire activity seems unlikely this month, even in the forecasted higher-odds areas.
“I don’t anticipate large, costly fires to really be likely in those areas for April,” he said in a video stream from the center exploring the forecast. “However, the risk for escaped backyard burns or escaped prescribed fires, I think, is correspondingly elevated due to the dryness we see in large fuels in those red-colored areas in April.”
According to the U.S. Forest Service and Bureau of Land Management’s summary of the 2018 Pacific Northwest fire season, there were about 3,700 wildfires in Oregon and Washington, burning 1.3 million acres, or about 2,000 square miles. That’s roughly the area of Delaware. The agencies estimated the fires cost about $707 million to fight.
Warm, dry and windy weather has already contributed to several fires around Southwest Washington. Nationwide, early-year fire activity has been low, with what little burning there was occurring in the Southwest, Western Oregon and the Southeast.
Mountain snowpack is largely near or above average for much of the Northwest, with late March snowpack at high elevations around 75-100 percent of normal in Washington and 100-158 percent of normal in Oregon, according to forecasters.
However, the rate at which that snowpack will melt, not its extent, is typically a more important factor in estimating fire season severity.
An average or slower rate of melting would keep higher-elevation, wooded areas less susceptible to fire until later in the year. A faster melt could dry them out sooner.
Wet, but not here
While California and other western states saw a wet winter, that wasn’t the case in the Pacific Northwest. Much of Oregon and Washington remain under dry to mild drought conditions. Longer-term forecasts from the National Weather Service Climate Prediction Center say dryness is likely to persist or develop further in Western Washington, North Central Washington and Northwest Oregon.
Bryan Henry, a meteorologist at the National Interagency Fire Center, said fire managers are watching Northern Washington and along the Canadian border, where there’s less snowpack.
“Drought conditions do remain, and it is slightly intensifying there. Conditions over the past several months have been drier than average, and the soil moistures are also reflecting very dry conditions as well,” he said in a video from the center. “With snowpack in those areas being around 70 percent of average, we’re expecting for that snowpack to come off slightly sooner than average, so there is an area of concern especially across Western Washington state, and then eventually extending eastward … possibly as far east as the Idaho Panhandle come June and July.”
In addition, climate forecasters say the Pacific Ocean is currently seeing a mild El Nino effect. Saltenberger said weak El Nino conditions are likely to continue through summer.
Historically, that’s meant higher odds of unusually high temperatures and lower odds of unusually low temperatures in the Northwest.
“From that, I conclude that in 2019, assuming that the El Nino designation continues, that we’re at good risk of being unusually warm going into the April-May-June period of 2019, based on what we’ve seen in past El Ninos,” he said.
How El Nino conditions affect the chances of precipitation is largely indeterminate for much of the Northwest, he added.