‘Wildfire-generated storm’ develops around Great Slave Lake

Last modified: July 12, 2022 at 8:05pm

A large wildfire along the North Arm of Great Slave Lake created its own massive thundercloud on Tuesday, experts reported.

Storm clouds carrying an orange-grey hue rapidly built up west and southwest of Yellowknife as Tuesday afternoon wore on, bearing with them an acrid smell of fire.

Lightning subsequently rolled across the city in the early evening, though this appeared to be a glancing blow at the edge of the storm.


Dr David Peterson, a meteorologist at the US Naval Research Laboratory in California who studies such phenomena, said on Twitter the “fire-generated thunderstorm” spawned near the North Arm was the 15th of the season in Canada.

NOAA and GOES-East images arranged by Zoom Earth show the growth of a pyrocumulonimbus cloud near Yellowknife on July 12, 2022.

A satellite meteorology institute at the University of Wisconsin-Madison also reported the “large and very hot wildfire” had produced a pyrocumulonimbus cloud, the name for the towering, signature clouds formed by wildfire-generated storms.

Dr Peterson’s previous work includes a study of a similar storm near Great Slave Lake in 2014, a notoriously bad wildfire season in the Northwest Territories.

In this instance, the culprit is a fire dubbed ZF009 by the territorial government.


ZF009 had burned some 32,500 hectares by Tuesday, making it the territory’s third-largest wildfire of the season to date.

Fire ZF009 is seen in a Sentinel-2 satellite image on July 7, 2022.
Storm clouds at the edge of a wildfire-generated storm gather beyond Yellowknife's sandpits on July 12, 2022
Storm clouds at the edge of a wildfire-generated storm gather beyond Yellowknife’s sandpits on July 12, 2022. Ollie Williams/Cabin Radio

The fire, on the west side of the North Arm, is being monitored but is not near any communities.

On its wildfire update page, the NWT government states ZF009 will “cause considerable smoke across most of the region – with especially intense smoke across Tłı̨chǫ communities.”

“Yellowknife should see varying intensity, which will at times be very high,” the webpage adds.