As Canadian wildfires escalate, outlook for U.S. is for a slower start

• The 2024 U.S. wildfire season is set to pick up over the coming weeks as hotter-than-average summer temperatures set in, according to the National Interagency Fire Center's (NIFC) forecast.

Context: Though last year was the least active in recent decades in terms of the amount of land burned, it was one of the deadliest on record due to the devastating fires that swept the Hawai'ian islands.

• The fires killed at least 101 people and razed the historic town of Lahaina.

The intrigue: Last year also featured expansive columns of dense wildfire smoke infiltrating areas unaccustomed to the hazard, including the big cities along the East Coast.

• With much of Canada mired in even worse drought conditions at the start of this fire season, and an unusual number of "zombie fires," smoke is already proving to be a cross-border problem.
• Fires in Mexico could also send smoke flowing northward into the southern tier of the country.

Threat level: With computer models signaling the likelihood of an unusually hot and dry summer across the West, even states like California, which was inundated with heavy rain and snow last winter, may see a significant uptick in its wildfire activity toward the latter portion of the summer into the fall, UCLA climate scientist Daniel Swain told Axios.

• Above-average potential for significant wildfires is expected for parts of Texas, New Mexico and Arizona throughout the summer.
• Elevated significant fire potential should evolve in central Florida in May and portions of southern Florida in June and should also develop in parts of Nevada, Utah, Idaho, Oregon and Washington starting in July, NIFC forecasts show.

Zoom in: Hawai'i is again at risk this year with most of the state expected to face above-average significant wildfire potential throughout the summer.

• The elevated potential is especially concerning for Maui and the Big Island, where drought conditions have persisted.

What they're saying: Swain is concerned about what computer models are showing for this summer, specifically the second half of the fire season.

• "There's pretty high confidence that this summer and autumn in particular are going to be highly anomalously hot across almost the entire West, even relative to recent standards, which is saying something," he said.
• "My prediction for the West general is that mild start, but very active finish," he said.

• "And this might be particularly pronounced in California where fire season might be pretty ho-hum, through maybe even late August or September, but could become really active in Autumn coinciding with offshore wind season," he said, noting that the wet winter allowed vegetation to proliferate.

Zoom out: Mike Flannigan, a wildfire expert at Thompson Rivers University in British Columbia, told Axios it is "highly unlikely" that Canada's season will meet or exceed last year's record-smashing severity, but it is likely to be unusually active given the drought and a possible warmer-than-usual summer.

• Canada's government predicts "well above average" or "above average" fire weather across its western provinces and territories throughout most of the summer, with conditions significantly worsening into the fall.
• As of May 15, almost 1,000 fires had burned over 832,000 acres across Canada. The 10-year average for this time of the year is about 306,700 acres.

The big picture: Human-caused climate change is leading to longer wildfire seasons in the western U.S. and has made severe seasons more frequent.

• The number of fire weather days has also gone up as the overall climate has warmed, research shows.
• In addition, wildfire activity in the boreal forests of Canada and the U.S. has increased in recent years in another climate-linked trend.

Go deeper: First major wildfires of Canada's season hit northern U.S. air quality