Ominous weather forecast as crews battle McKinney Fire

Hazardous weather conditions continued to exacerbate the McKinney Fire over the weekend, with moderate to severe thunderstorms, record heat and wind gusts of up to 60 mph inhibiting fire crews as they were trying to fight the rapidly growing fire.

The wildfire broke out Friday afternoon in the Klamath National Forest near Yreka, about 15 miles from the Oregon border. It swelled to 18,000 acres overnight, burning 51,468 acres in total Sunday morning, the US Forest Service said. There is no containment.

Hot, dry and windy weather is currently favoring the fire’s growth, Brad Schaaf, a meteorologist with the National Weather Service office in Medford, Oregon, told SFGATE on Sunday.

“There were several thunderstorms in the area last night which can create gusty and erratically changing winds that very quickly push the fire in different directions,” Schaaf said. “And lightning is always dangerous because it can start new fires, and it’s dangerous for firefighters, or anyone, to be in the area.”

He added that the surrounding wind gusts ranged from 40 to 60 mph, noting that wind speeds of 58 mph or more constitute a “severe thunderstorm” warning. Brett Lutz, another meteorologist with the Medford office, said 62 lightning strikes built from the blaze’s huge pyrocumulus cloud fell within 30 miles of its point of origin on Saturday evening. Just over a half inch of rain came in a few short bursts, along with thunderstorms and gusty winds, but any moisture was likely evaporated by the fire as it fell, Lutz said.

“When things happen like this in a fire, it gets really tough and people have to take a step back,” Lutz said. “Monsoon humidity entering a hot, dry environment is a great firefighting hazard.”

Meanwhile, thick blankets of smoke are also choking the area as far north as Rogue Valley. Schaaf described the situation as “a mixed bag.” The smoke helped inhibit the development of thunderstorms over Rogue Valley and quell some of the region’s sweltering heat. Temperatures in the area are in the high 90s to 100s, with Montague reaching 110 degrees and breaking daily heat records. Air quality is reaching “unhealthy” to “dangerous” levels, according to AirNow.

“We advise people to pay attention to the air quality in their area, especially if they are near the fire, as the smoke will continue for the next few days as the fire develops,” Schaaf said.

Schaaf is hoping for some respite with a few days of slightly cooler temperatures, which are expected to range in the low to mid-90s before rising again next weekend. But a red flag warning for heavy lightning over dry vegetation is in effect until Monday; Isolated and scattered thunderstorms are expected in the afternoon or early evening. Forecasters believe they will move east of the Klamath River and south of Scott Bar in Siskiyou County, through Montague and Eureka.

“What we would expect is that thunderstorms south of the fire could move over the fire, which is dangerous,” Schaaf said. “On Monday we could see more potential for strong and severe storms in the region, as well as gusty winds up to 60 mph and occasional to heavy lightning.”

Lutz noted a chance for “significant rain” to increase through Monday evening, which could help slow the fire. He said half an inch of rain can dampen the potential for fire spread for 12 hours to a few days, depending on subsequent weather conditions. However, the thunderstorms are also creating concerns for new fires due to high winds and lightning strikes hampering firefighting efforts, so the impact, if any, remains to be seen.

“The weather service is working closely with firefighting partners to monitor the weather and communicate any hazards as quickly as possible,” Schaaf said.