McKinney Fire weather outlook: Thunderstorms could intensify deadly California wildfire

Dry lightning and gusts from scattered thunderstorms could stoke more extreme behavior early this week on or near the McKinney Fire burning in Northern California, which exploded in size and intensity over the weekend, killing at least two people.

The state’s largest wildfire of 2022 by far, the McKinney Fire surpassed 55,000 acres, or 86 square miles, as of a Monday morning update from Cal Fire and the U.S. Forest Service. The blaze, which ignited Friday afternoon at Klamath National Forest in Siskiyou County, is 0% contained.

The Siskiyou County Sheriff’s Office announced Monday two people were found dead Sunday morning inside a burned-out vehicle within the fire zone.

As at least 850 fire personnel raced to rein in the fire, which was burning a little more than 5 miles west and northwest of Yreka as of Sunday and forced the evacuations of about 2,000 people, authorities also braced for unpredictable monsoon weather that could bring a combination of dry lightning and wind gusts to the fire zone.

The Forest Service in a 10 a.m. incident update Monday said rainfall overnight helped keep fire growth minimal, but that vegetation in the area remains “extremely dry.”

Weather service forecasts showed an “uncertain weather pattern” blanketing California. Scattered, isolated thunderstorms were more likely Monday but could linger into Tuesday, according to the National Weather Service.

The weather service early Monday issued a red flag warning for severe wildfire risk in far northern portions of California, including central Siskiyou County.

“Heat, instability, and increasing moisture along with multiple low pressure impulses moving through this afternoon/evening and again Tuesday are expected to bring isolated to scattered thunderstorms and abundant lightning on dry fuels to the area,” the agency’s Medford, Oregon, office wrote in a 6 a.m. bulletin.

By Monday afternoon and evening, “lightning threat will be greatest from the Cascades eastward as well as over western Siskiyou, Josephine and western Jackson Counties,” weather officials wrote. Josephine and Jackson counties are in Oregon.

“On Tuesday, the lightning threat will be greatest from the Cascades east, Siskiyous south and into southwestern Jackson County.”

The Forest Service in its own incident report Monday said gusts up to 50 mph could develop near thunderstorm cells. That means the McKinney Fire could spread rapidly if thunderstorms develop.

“Fire growth is expected to spread in all directions,” the Forest Service wrote in a 48-hour incident projection Monday morning.

The blaze is burning in timber, tall grass and brush, all of which are extremely dry because of California’s ongoing drought.

Dry lightning – thunderstorms with minimal accompanying rainfall making it to the ground – have been a major source of wildfire danger in California in recent years.

Many of the largest and most dangerous incidents of 2020, including the North Complex in Butte and Plumas counties that killed 16 people as well as the more than million-acre August Complex that ignited one day earlier, started during a massive thunderstorm system that saw dry lightning pass through the Bay Area and Northern California in mid-August of that year.