June means trouble for B.C. wildfires with hot, dry forecast set to compound drought

The Donnie Creek wildfire. Courtesy: BCWS.

Underlying drought, unseasonably warm temperatures last month and hot, dry conditions in the June forecast mean “the table has been set” for significant wildfire activity this summer, an official with the British Columbia Wildfire Service says.

Lead fire weather forecaster Matt MacDonald said he and his colleagues have been waiting to see if this month might bring desperately needed rain.

“The classic adage we hear every year is the intensity of the fire season will greatly depend on the amount of rain received in June,” he said.

Now that it's here, the June forecast does not bode well.

MacDonald said the service has been looking at how much rain would be needed to alleviate persistent drought conditions and lower the risk of wildfire. They found it would require two to three millimetres of rain per day for 10 to 20 days in a row, he said.

“I can almost guarantee that is not going to happen,” he said.

A day or two of heavy rainfall here and there isn't likely to reduce the risk, said MacDonald, explaining that it's more likely to run off than replenish moisture in soils that lose their capacity to absorb water after a prolonged dry spell.

The Donnie Creek wildfire currently burning across more than 1,700 square kilometres north of Fort St. John offers a perfect example, he said.

The blaze received about 40 mm of rain on May 22 and 23, about 10 days after it was discovered, which slowed its activity for a day or so, he said.

But within three days, it was burning at class-five intensity on a scale of one to six, with “crown fire” igniting and consuming whole trees, MacDonald said.

Forty or 50 mm of rain sounds substantial, “but given the underlying drought conditions, it's only a drop in a very empty bucket,” he said.

B.C. had a relatively dry January with snow packs significantly below normal levels before they caught up in March and April, as temperatures stayed relatively cool.

Then, “May came in like a lion,” MacDonald said of the record-shattering heat wave that helped spur early-season wildfires in northeastern parts of the province.

Matt Loney, a meteorologist with Environment and Climate Change Canada, said it was either the first- or second-warmest May ever recorded for at least 15 stations in B.C.

With spring drawing to a close and hotter-than-normal temperatures in the forecast again, MacDonald said he expects to see grass drying out, turning yellow and becoming primed for potential ignition by the third or fourth week of June.

“We're going to start to turn the corner and those deeper, persistent drought conditions are going to begin to rear their ugly faces,” he said.

The story of the 2023 wildfire season actually began last fall, he said.

Unseasonably warm, dry conditions last October meant an extension of summer activities for many in B.C., but they also “cranked up the drought dial,” he said.

The province then headed into an early winter freeze and when spring 2023 arrived “we uncovered even deeper drought conditions” in many areas, he said.

“It has a lot of us concerned, to be honest,” he said.

“I think we're lining up for what could be a very active fire season.”

MacDonald said there are different types of drought, and they don't always occur at the same time.

This year is “one of the rare occurrences where all the droughts, no matter how you define them, be it rivers, soil moisture, or the fuels, the forests, are all very clearly indicating elevated drought” in pockets of the province, MacDonald said.

Right now, those pockets extend from the Cariboo region west of the Fraser River - around 100 Mile House to Prince George - over to the Smithers area and the Peace Region to the east, where B.C.'s most significant fires are currently burning, he said.

Suspected causes are currently split 50/50 between humans and lightning this year in B.C., MacDonald said.

While people tend to picture a cigarette flicked out the window of a car as the spark for human-caused wildfires, that's not so common anymore, he said. Ignition could come from a train, a chainsaw, a campfire that hasn't been fully doused, or from people running gas-powered vehicles in the bush.

“If you're riding a dirt bike or a quad or a side-by-side, maybe you don't have a spark arrestor on your muffler, on your exhaust,” MacDonald said.

“We're really trying to encourage people to be extremely cautious.”

This report by The Canadian Press was first published June 4, 2023.