As fire consumes vast areas of the U.S. Pacific Northwest, wildfire responders are casting a nervous eye on a dangerously flammable landscape, with forecasts showing that some regions are becoming a tinderbox beyond anything measured in recent memory.
For weeks, fires in Ontario and British Columbia have menaced communities and filled skies with smoke, prompting a threat of retaliation from U.S. President Donald Trump.
But increasingly large parts of the U.S. are now on fire. In Utah and Colorado, more than 235,000 acres have burned. In Oregon and Washington state, the total has now exceeded 1.8 million acres. July has not yet come to an end, but that is already seven times last year’s total for those states.
Worse may lie ahead, in places where landscapes of timber and chaparral have grown exceedingly dry, desiccated by a winter without much moisture and a summer of scorching heat.
Wildfire expert offers reality check for U.S. lawmakers who castigated Canada for smoke
U.S. authorities divide the Pacific Northwest into 12 zones. In nine of them, the energy release component, or ERC, is expected to reach or exceed the 95th percentile of typical annual readings in the coming week.
In at least one zone, the southeast corner of Oregon, the level is expected to reach heights never seen locally in the two decades the ERC has been calculated.
Firefighters battle the Bench Fire in Warm Springs, Oregon, on July 25.Noah Berger/The Associated Press
The ERC is a measure of how much energy is expected to erupt from a section of land if it is set ablaze, based on how much fuel is available and how dry it is. It does not predict whether fire will break out or whether the flames will be whipped by wind. What it does indicate is how much the landscape is primed for inferno.
“You can think of it as an index of flammability. The bigger the number, the more flammable it is, the more energy will be released if there is a fire,” said Larry O’Neill, an Oregon-based climatologist.
“We’ve already seen how flammable central and eastern Oregon are. This suggests we can go even worse.”
Forecasts suggest scorching dry weather ahead and winds reaching 50 kilometres an hour in parts of Oregon where fire has already broken out.
“When you’re blowing winds like that over historically flammable fuels, all we need is one little spark for a big thing to happen,” said Mr. O’Neill, who is also a climate scientist at Oregon State University.
He was in eastern Oregon two weeks ago when a lightning storm lashed the state. Driving the next day, he spotted over a dozen smoke columns. Never before had he seen wildfire start and grow so easily. “These are conditions we don’t typically see any time during the year. To have them in mid-July – it’s astounding,” Mr. O’Neill said.
The outbreak of fire marks an explosive new chapter after a winter with little precipitation. In April, eight states – Arizona, Colorado, Idaho, Nevada, New Mexico, Oregon, Utah and Wyoming – reported record low snowpack levels. Then came a warm spring and, in recent weeks, both lightning and wind.
In the western U.S., “this is about the time of year when we generally see fire activity kick up, and the coming heatwave has a high potential for initiating large, high-energy fires across the region, especially if aided by some dry lightning,” said Park Williams, a professor at the University of California, Los Angeles who studies fire and climate.
Firefighters watch as a helicopter drops water on the Summit Fire in Llano, California, on July 10.Ethan Swope/The Associated Press
Some fire-prone parts of the U.S. have, so far, seen relatively muted fire activity this summer. California, for example, emerged from winter with a comparatively more robust snowpack and has not seen “sustained periods of really extreme fire weather,” said Brandon Collins, a regional ecologist with the U.S. Forest Service.
But the conditions taking shape just to California’s north are more troublesome. The forecast of record-setting flammability in parts of Oregon is “absolutely a warning sign,” said Mr. Collins.
It is driven at least in part by lack of rain. Mike Flannigan, science director for the Canadian Partnership for Wildland Fire Science, has been watching forecasts for precipitation across the region – and seeing almost nothing.
“There’s no rain for the next 15 days in almost all of Oregon, almost all of Washington, a good chunk of California and Nevada, Idaho, Montana,” he said.
“I expect this area to just continue to burn, burn, burn.”
The Aspen Acres Fire burns on July 3 in Colorado City, Colorado.Michael Ciaglo/Getty Images
In Canada, intense fire in southern parts of B.C. has also destroyed some homes and closed highways. But forecasts suggest a greater likelihood of precipitation for the province than for much of Washington and Oregon.
“The next couple of weeks are going to be really rough for fire in that area,” Mr. Flannigan said.
Wildfire fighter Joe Stutler has seen this coming for months. He lives near Bend, Ore. This winter, he golfed in January. In the months since, warm temperatures have repeatedly set daily records. Summer has brought unusually warm evenings.
Then a week ago, a wildfire broke out near his home outside Sisters, Ore., shooting pyrocumulonimbus clouds – thunder clouds created by wildfire – high into the atmosphere, above the altitude that jetliners fly.
Mr. Stutler, now in his 58th fire season, has seen situation reports suggesting some of the current fires may not be contained until November. And with combustible conditions and a chance of more dry lightning in the forecast this week, more may come.
“Who knows what it is going to bring,” he said. “But it’s going to be a long season.”