What are holdover fires? Thousands of hectares burn in northeastern B.C.

Thousands of hectares of land in northeastern B.C. are burning from holdover fires, with officials saying persistent drought conditions through the winter and a challenging wildfire season last year have "amplified" challenges for crews.

Officials gave a wildfire update Monday morning, saying additional properties were placed under evacuation order due to fires burning in the northeast corner of the province. While most current evacuation orders are due to the Parker Lake wildfire, which is burning just outside of the town of Fort Nelson, some are in effect because of holdover fires.

BC Wildfire Service describes a holdover fire as one that remains dormant or undetected for a "considerable period of time after it starts."

"It is possible for large fires to move deep underground and 'slumber' undetected for a period of time. Heat can simmer underground for days, weeks, or even months," an information bulletin from BCWS explains. "As the weather dries out and temperatures rise, these fires can flare up."

One holdover fire that remains out of control in the Prince George Fire Centre is Patry Creek, which is measured at 34,306 hectares. Southeast of that is the 60,615-hectare Nogah Creek holdover fire, which is also classified as out of control. Both fires have led to nearby evacuation alerts and orders.

"In the past, winter conditions are what put out a lot of holdover fires," Emergency Preparedness Minister Bowinn Ma said Monday. "In this case, what we've seen is that due to higher temperatures and persistent drought through from last year, many of these holdover fires were not put out the way that they normally are."

Cliff Chapman, director of BCWS, explained during Monday's update that the province has dealt with holdover fires for decades, saying they aren't new for B.C.

He explained some fires that remained underground through the winter were "not producing heat signatures" because of snow resting on top.

"Obviously the impacts of how much landscape was on fire last year amplified this challenge for the BC Wildfire Service, but more importantly for citizens of northern B.C. in particular," he said, adding the BCWS team anticipated holdover fires flaring up in that region, resulting in an incident management team being sent to Fort Nelson. That team arrived before the Parker Lake fire broke out and forced thousands from their homes.

"I am proud of the BC Wildfire Services team and everyone in the northeast for coming together to do everything we could to plan for these fires, but obviously they have come out of their existing boxes from last year and we continue to respond as we can," Chapman said.