Heat dome heats mountain snow in the western US, a flashy warning of fire season
Mountains that usually see a lot of snow in March are brown this year, thanks to the spring heat that baked the western US for much of the second half of March. That is a warning sign of a fire season, which is already rising.
John Abatzoglu, a professor of climate science at the University of California Merced, said everything is “preparing for a potentially devastating fire season in the west … the warning signs are flashing.”
Heat wave take it easy on the weekend after temperatures 11 to 17 C above normal – highs in the 30s and 40s most days in some states..
Research released on March 20 found that a wave of this warming is “virtually impossible” without climate change caused by human-caused CO2 pollution, mainly from fossil fuels.
March heat records were broken in more than a dozen states, rapidly melting snow in the western US mountains.
Early melting of ice has been linked to a long fire timeas it dries out the area and gives more time and opportunity for fires to ignite and spread, said Jared Balik, a research scientist at Western Colorado University in Gunnison, Colo.
But if the snowpack was low before the early snowmelt, that doesn’t just lead to a forest fire. The risk of more severe fires also increases – reducing the chance of forest regeneration after a fire, Balik found in a new study. published last week.
This is bad news, given that as of Monday, snowpack was on track to be record low for nearly every destination in the western USaccording to University of California Los Angeles climate scientist Daniel Swain.
And not just at ski resorts — in the western US, Abatzoglu said, the snowpack is the lowest it’s been in 20 to 30 years.
Amid record low snow, fire season is off to a good start
In Colorado, where Balik lives, he saw record-breaking snowpack all winter. And as of Friday, when he spoke to CBC News, almost everything is gone. Balik said it’s the first time he’s seen snowmelt in the decade he’s lived in the region, and a month to a month and a half earlier than normal.
That’s given the fire season as a start for both In Colorado and neighbors Nebraska.
“Colorado is now covered in smoke from those Nebraska fires,” Balik said. As of Monday, they have already it burned more than 25,000 hectares.
Wildfires have also occurred reported in California. Most have been the smallest so far and grassy areas, but Abatzoglu said they suggest that the grass in the region is dry enough to carry the fire.
When he was in central California, it was over 30 C most days, and the greens that used to be green in spring were turning brown. “It’s incredibly warm,” he said Friday. “I kept the air conditioner on last week.”
Low snowpack leads to more intense wildfires
Balik’s research shows that conditions now can lead to more dangerous fires later.
The US Department of Agriculture tracks the amount of water contained in the snowpack in winter – which is important later in the year not just for plants, but for forests.
“It provides the water that trees rely on during their growing season,” Balik said. Less snow means drier, more flammable trees – and more severe fires. His team demonstrated this by correlating satellite measurements of snowpack with satellite measurements of forests before and after wildfires during multiple fire seasons.
“We were surprised that there was a strong relationship between the decline in snowpack and the fire season that followed the warming.”
In less severe fires, he said, the flames may burn dead wood to the ground, leaving mature trees intact.
On the other hand, a big fire in a dry forest destroys everything, including the seeds that allow the forests to grow again.
“That creates an opportunity for other types of plants to attack the system and take the place of the existing forest,” said Balik. It could be convert forest to grassland or scrublandhe added, changing how much carbon is stored in the area and impacting water availability and wildfire habitat.
What can be done to reduce the risk?
While snowpack is seeing a long-term decline due to climate change across North America, Balik said, “It’s not all doom and gloom … every winter is another chance to get a snowpack.”
Climate change may lead to less snowy years, but weather patterns like El Niño and La Niña bring snowier winters from time to time, the study found.
And those years, says Balik, “are the best opportunity to do the prescribed heat.” That can reduce the amount of fuel available to wildfires, reduce their intensity, and such arson fires are easier to control and contain in wet years.
Does this work in Canada?
Hossein Bonakdari, a professor at the University of Ottawa, recently satellite and drought data have been used to look at factors that cause severe wildfires that destroyed more than 8,000 square kilometers in Manitoba last May and how they can be predicted.
That came after unusually low snow cover led to early snow loss, and an early heat wave that brought temperatures up to 37 C in Winnipeg in May.
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Bonakdari said that in Canada, as in the US, low snowpack is a major risk for wildfires, especially in the west. However, he added that other factors, such as extreme heat and drought, may be more important in the boreal forest.
Bonakdari said there have been drought conditions across Canada in the past few years, too warmer temperatures are expected in 2026 due to El Niñomany parts of Canada are still at risk of a severe fire season, although the recent US heat wave did not cross the border.
Meanwhile, in the US, Abatzoglu is worried about how widespread the heat wave is – and that is why the risk of fire is increasing -.
“Actually, that’s all [the] in the western US,” he said. This makes it unlikely that states will be able to borrow firefighting services from other areas.
But Abatzoglu said it is not too late for the risk to change: “I hope for April showers.”
