Find updates on the Lava Fire from the U.S. Forest Service.A wildfire in Siskiyou County nearly doubled in size on Sunday, growing to more than 550 acres and pumping out a massive cloud of smoke that rose over 25,000 feet into the sky and made Mount Shasta appear as if it were an erupting volcano. The so-called Lava Fire burning near the community of Weed is 20% contained. "Very impressive shot of the #LavaFire, currently burning on western flank of Mt. Shasta," Daniel Swain, a climate scientist with the Institute of the Environment and Sustainability at UC Los Angeles, wrote on Twitter. "In the pre-social media era, I suspect more than a few folks would have been concerned that Shasta was experiencing a volcanic eruption (which, to be clear, it is not!)."The Lava Fire was one of four confirmed fires that started from lightning strikes on Friday in the U.S. Forest Service's Shasta-Trinity National Forest, according to the incident report. Crews jumped on the incidents quickly and only the Lava Fire is still burning. The blaze is moving across rough, rocky terrain 3.5 miles northeast of Weed and 4.5 miles southeast of Lake Shastina, according to the Forest Service.The Forest Service posted evacuation warnings Sunday at 6 p.m. for areas along State Route 97 north of Weed and for Angel Valley Road, Carrick Addition and Solus Drive.Firefighting efforts Sunday were hindered by extremely hot and breezy conditions. "Winds are expected over the next several days over the burn site," the Forst Service said. "Sunday will be the hottest day with temperatures likely reaching near the triple digits. Daytime humidities will be even lower on Sunday and winds will shift to be from the south to southeast and begin increasing through the day on Sunday, even through the evening."