Evacuation warnings were in place in for parts of north and west Yreka by Saturday afternoon; areas closer to the fire, which is burning in the Klamath National Forest near the Oregon border, were under evacuation orders. In a sign of its extreme behavior, the wildfire sent a 50,000 foot pyrocumulonimbus cloud — a plume generated by intensely burning fires — into the air, pushing smoke high above the clouds, climate scientist Daniel Swain noted on Twitter. On Saturday, officials said firefighters and air resources were continuing an “aggressive extended attack” on the fire, but that the cumulus clouds in the area “have potential to exacerbate fire behavior.” No information is available on the cause of the fire. The McKinney fire in Siskiyou County seen at around 7:15 a.m. Saturday from the Antelope Mountain Yreka 1 observation camera. Cal Fire Remarkable satellite imagery this AM in NorCal/OR. #McKinneyFire exploded last night, generating massive pyrocumulonimbus cloud ~50,000 ft tall (!!). You can see smoke at two different heights: most in troposphere, but some (possibly) injected into stratosphere (!). #CAwx #CAfire pic.twitter.com/Ri7IKcsnk8 — Daniel Swain (@Weather_West) July 30, 2022 On Saturday afternoon, a meteorologist with the National Weather Service in Medford, Ore., which is the forecast office for Siskiyou County, said that there thunderstorms could develop over the fire into the late afternoon and evening. The area around the fire was under a fire weather watch through Monday as abundant lightning was expected over dry fuels. “Fire managers are expecting a very dynamic day on the fire as predicted weather is expected to be problematic for the firefighters,” an incident update said. Crews from multiple agencies are battling the flames. Firefighters from the U.S. Forest Service are currently in charge, but a California Incident Management Team, which coordinates agencies like the Forest Service and Cal Fire, was scheduled to take over Sunday morning. Danielle Echeverria is a San Francisco Chronicle staff writer. Email: [email protected] Twitter: @DanielleEchev