A helicopter pilot was killed in a crash in western Canada in the third death in recent days connected with efforts to fight fires in the country's worst wildfire season on record.

The pilot was the sole occupant of the helicopter when it crashed Wednesday near Haig Lake in northwestern Alberta province and forestry workers were unable to resuscitate him, the Royal Canadian Mounted Police said. He was declared dead at a nearby airport.

Police said the pilot was a 41-year-old man from Whitecourt, Alberta, but did not release his name.

"There are a lot of people across this country who have been stepping up during these very, very difficult forest fires, protecting their families, protecting their communities, protecting their fellow citizens," Prime Minister Justin Trudeau said. "And to have lost three firefighters, or individuals helping out in fighting the fires, is heartbreaking."

Last week, Devyn Gale, a 19-year-old firefighter, died after a tree fell on her near Revelstoke, British Columbia.

CANADA BATTLES WORST-EVER WILDFIRE SEASON, AS NORTH AMERICA ENGULFED IN SMOKE

Adam Yeadon, 25, died Saturday while fighting a wildfire near his home in Fort Liard, Northwest Territories.

Transportation Safety Board spokesman Chris Krepski said two investigators were due to arrive at the remote scene of the helicopter crash on Thursday.

He said an emergency locator transmitter signal was received Wednesday at about 6 p.m. He said the downed aircraft was in a marshy area.

Krepski added that it was operated by Valhalla Helicopters, based in West Kelowna, British Columbia. The company declined to comment.

As of Thursday afternoon, Alberta had 117 active wildfires, 17 of which were considered out of control.

Thousands of fires have scorched more than 42,000 square miles across the country so far this season.