VANCOUVER — More than 110 active wildfires were burning across British Columbia and Alberta on Saturday, with thick smoke plumes drifting south into Washington, Idaho and Montana, after the driest April on record across the Canadian Prairies set the stage for what fire officials are calling the earliest serious fire start in a generation.

The BC Wildfire Service said 73 fires were burning in the province as of Saturday morning, 18 of them classified as “wildfires of note” for their threat to communities or critical infrastructure, including a 9,400-hectare blaze northwest of Williams Lake that prompted the evacuation of approximately 1,800 residents Friday night and a fast-moving fire on the eastern flank of the Okanagan Valley that closed a stretch of Highway 97 north of Vernon. Alberta Wildfire reported 38 active fires across the province’s northern and west-central forest zones, with the largest, a 6,200-hectare fire south of High Level, burning under extreme conditions and forcing the evacuation of several Indigenous communities.

“We are watching fire behavior in the first week of May that we would not normally expect to see until the back half of June,” said Cliff Chapman, director of provincial operations for the BC Wildfire Service, at a televised briefing in Kamloops. “Crews who would still be in pre-season training are deploying as initial-attack teams. We are skipping a chapter of the year.”

The early outbreak follows a winter that left snowpack at 64 percent of normal across the southern interior of British Columbia and 71 percent across the central Alberta foothills, according to the most recent provincial snow-survey bulletins. Combined with an April in which Calgary, Edmonton, Kamloops and Prince George all recorded less than a third of average precipitation, the result has been forest-floor moisture readings that fire scientists say are running four to six weeks ahead of the historical curve.

Canada’s Minister of Emergency Preparedness, Charles Sousa, said in Ottawa that the federal government had approved British Columbia’s request for assistance under the national Mutual Aid Resource Sharing arrangement, and that Canadian Armed Forces airlift support and additional crews from Quebec, Ontario and New Brunswick were being moved west. He also confirmed that Ottawa had accepted a U.S. offer of five Type 1 incident management teams and four air-tanker groups under the long-standing North American fire-sharing compact.

“The fact that we are activating cross-border support on May 2 should tell everyone in this country something important about the season ahead,” Sousa said. “We are in the position we expected to be in by late June. The summer is a long way away, and our resources will be tested.”

Air quality alerts blanketed a wide swath of the Pacific Northwest by Saturday afternoon. The Washington State Department of Ecology issued advisories for nine counties east of the Cascades, with hourly fine-particulate readings in Omak and Colville crossing into the “unhealthy” range for the first time this year. In Idaho, the panhandle communities of Sandpoint and Coeur d’Alene were under air-quality watches, and Montana’s Department of Environmental Quality reported visibility of less than two miles in parts of Flathead County.

Pediatric clinics in Spokane and Kalispell said they were already seeing an uptick in visits for asthma exacerbations and other smoke-related symptoms. “We had the asthma binder out of the cupboard weeks earlier than we wanted to,” said Dr. Eileen Yamashita, a pediatrician at Sacred Heart Children’s Hospital in Spokane. “Families that learned to live with smoke seasons in August and September are now being told to keep kids inside on the first weekend of May. The psychological cost of that is real.”

The 9,400-hectare Chilcotin Lake fire west of Williams Lake remained the most aggressive incident in British Columbia. Cariboo Regional District officials said the blaze had crossed an old firebreak from the 2017 season overnight and was advancing on a rural area dotted with ranches and a small cluster of homes near the community of Riske Creek. Air tankers based at Kamloops and Prince George were running back-to-back drops through the day, and helicopter crews equipped with bucket lines worked the fire’s southeastern flank.

“This is country I have fought fire in for twenty-six years, and I have never seen the duff layer this dry on the second of May,” said Marc Doucette, an incident commander with the BC Wildfire Service, by satellite phone from the fire camp at Riske Creek. “We are taking the same approach we would take in late summer, because the fuels are giving us a late-summer fire.”

In Alberta, the High Level fire prompted the evacuation of the Dene Tha’ First Nation communities of Bushe River and Meander River, with Indigenous Services Canada confirming that approximately 1,100 residents had been moved to temporary accommodations in High Level and Peace River. A spokesperson for the Dene Tha’ said elders and families with young children had been prioritized for buses, while a small contingent of community members had stayed behind with structural-protection equipment provided by the province.

Climate researchers said the conditions reflected a now-familiar pattern of compressed snowmelt and early-season drying that has been documented across the boreal interior for more than a decade. “The fire weather index values we are recording today in the Cariboo and the Peace are values that, in the climate of the 1990s, we would have expected once or twice a decade in the third week of July,” said Dr. Mike Flannigan, a wildfire scientist at Thompson Rivers University in Kamloops. “We are not setting outlier records anymore. We are watching the new normal arrive on the calendar three weeks earlier each cycle.”

Insurance industry analysts said it was too early to put a number on losses but warned that a sustained May fire season would put additional pressure on Canadian reinsurance markets already absorbing the cost of the 2024 and 2025 seasons. “Underwriters were budgeting for a June start,” said Renata Kowalski, a senior analyst at the Insurance Bureau of Canada. “If May behaves like this, the math for the rest of the year gets uncomfortable quickly.”

Provincial officials in both British Columbia and Alberta said additional evacuation alerts and possible burn bans would be reviewed through the weekend, with revised situation reports expected Sunday evening.