WASHINGTON, July 18 (Reuters): Wildfire smoke blanketed the eastern US from the Great Lakes to Washington, D.C. on Friday, floodwaters tore through Texas's Hill Country for a third day, and new fires erupted in the Pacific Northwest overnight, with 68 large blazes now burning in 15 states.
Millions of Americans faced hazardous conditions and orders to stay indoors, as the country's summer weather extremes converged on three fronts at once: a smoke-choked East, rising water in the South, and fast-spreading flames in the West.
Firefighters are now battling 68 large fires nationwide, up by nearly two dozen from a day earlier. Some 17 new blazes broke out in the Pacific Northwest after a run of lightning strikes made it the most active fire region in the country, according to a summary from the National Interagency Fire Centre.
More than 17,400 personnel, 140 helicopters and four military C-130 air tanker crews are now deployed across the US to battle wildfires, with record-low snowpack in the Mountain West and drought pushing fuel conditions to the type of dry and fire-prone levels normally not seen until mid-August, according to the NIFC.
Nearly 3.72 million acres (1.51 million hectares) have burned nationwide so far this year, outpacing last year's mid-July tally by over 1 million acres.
Jesse Berman, a professor at the University of Minnesota School of Public Health whose research focuses on how extreme weather affects health, said simultaneous disasters like those playing out now can make them more dangerous.
"These are compound events, and that can sometimes make the impacts of them far worse than what we would experience with any one of these events individually," Berman said.
University of Pennsylvania climatologist Michael Mann said the extreme weather events were linked by a wave pattern in the jet stream that may be a phenomenon known as "resonance." This occurs when large waves in the jet stream become amplified and trapped, causing extreme weather to persist over a region for longer periods, creating more chaos.
Mann said his research shows that human-driven climate change has led to a tripling of these stalled jet stream events since the 1950s.
Climate scientist Jonathan Overpeck, dean of the University of Michigan's School for Environment and Sustainability, said rising temperatures are driving disasters through the same basic mechanism, even though the effects can look opposite.
A warmer atmosphere pulls moisture out of soil and vegetation more aggressively, which has left Canada's landscape drier and more fire-prone. At the same time, a warmer atmosphere can hold more water vapor before releasing it, which is producing the kind of intense, heavy rainfall now battering Texas.
"What climate change is doing is it's rolling the dice so that you're going to get drier conditions and more wildfires at the same time as you're going to get more rain," said Overpeck.
Meanwhile, US President Donald Trump on Friday blamed Canada for wildfire smoke spreading across the United States and said he would add the "incalculable cost" of dealing with the pollution to existing tariffs on Canadian goods.
Heavy smoke from hundreds of Canadian fires enveloped a swath of the US from the Midwest to the Northeast on Thursday and Friday, prompting warnings to residents to stay indoors.
Trump, who has a combative relationship with Prime Minister Mark Carney, said he would be calling the Canadian leader to find out what he planned to do about the "totally unacceptable" situation.
"We are holding Canada responsible for the fact that they are not properly maintaining their Forests ... and the United States is being unnecessarily invaded by filthy, polluted, and unhealthy air," he said in a Truth Social post.
"This is Willful Negligence, and becoming a yearly occurrence, costing the United States Billions of Dollars, which cost of this pollution must of necessity be added to the TARIFFS Canada is currently paying."
Canada's minister of emergency management and community resilience, Eleanor Olszewski, said the government has invested C$12 billion ($8.56 billion) in forest sustainability and fire prevention since 2020 as the country faces increasingly drier, warmer weather.
She also cited a long history of US-Canadian partnership in fighting wildfires on both sides of their border.
"At this time, our first priority is protecting Canadians and keeping communities safe," Olszewski said in a statement.
