Crews battling the largest wildfire in California this year braced for thunderstorms and hot, windy conditions that could lead to additional fire growth on Sunday as they worked to protect remote communities.

The McKinney Fire was out of control in Northern California’s Klamath National Forest on Sunday, with thunderstorms looming just south of the Oregon state line, according to US Forest Service spokesperson Adrienne Freeman.

“The fuel beds are so dry that they could just erupt from the lightning,” Freeman explained. “These thunder cells are accompanied by gusty erratic winds that can blow fire in all directions.”

According to a Sunday incident report, the fire grew to more than 80 square miles (207 square kilometers) in size just two days after erupting in a largely unpopulated area of Siskiyou County. The cause was being investigated.

The fire charred trees along California Highway 96, and the scorched remains of a pickup truck sat in a highway lane. Thick smoke blanketed the area, and flames burned through hillsides near homes. In one neighborhood, where a brick chimney stood surrounded by rubble and scorched vehicles, the fire Sunday cast an eerie orange-brown hue.

A second, smaller fire sparked by dry lightning Saturday threatened the tiny town of Seiad, according to Freeman. The two California fires threatened approximately 400 structures. Authorities have yet to confirm the extent of the damage, stating that assessments would begin once it was safe to enter the area.

According to Courtney Kreider, a spokesperson for the Siskiyou County Sheriff’s Office, a third fire on the southwest end of the McKinney blaze prompted evacuation orders for approximately 500 homes on Sunday. Crews had been on the scene since late Saturday, but the fire “became active and escaped its containment line” on Sunday morning, according to the office. “Several people in the sheriff’s office have been affected by evacuation orders as a result of the fires,” she said, “and they’re still showing up to work, so (a) very dedicated crew.” According to her, a deputy’s childhood home was destroyed by fire on Friday.

The McKinney fire “remains 0 percent contained,” according to a late-night Facebook post from the Siskiyou County Sheriff’s Office.

As the McKinney fire threatened, some residents chose to stay, while others obeyed evacuation orders.

Larry Castle and his wife, Nancy, were among the approximately 2,000 residents of the Yreka area who were ordered to evacuate. They left Saturday with some of their prized possessions, including Larry’s motorcycle, and took their dogs to their daughter’s house near Mount Shasta.

After witnessing the explosive growth of major fires in recent years, Larry Castle said he wasn’t taking any chances. A fire that started in grasslands near the town of Elmo in northwest Montana had spread to about 17 square miles (44 square kilometers) after advancing into forest. Crews were working along the fire’s edges on Sunday, and aircraft were expected to continue dropping water and retardant to help slow the fire’s progress, according to Sara Rouse, a spokesperson for the interagency team assigned to the fire. She predicted high temperatures and erratic winds.

Highway 28 between Hot Springs and Elmo was reopened, but drivers were advised to keep an eye out for fire and emergency personnel. According to Rouse, visibility in the area was poor.

The Moose Fire in Idaho’s Salmon-Challis National Forest has burned over 75 square miles (196 square kilometers) of timbered land near the town of Salmon. By Sunday morning, it had been contained to 21% of its original size. Pila Malolo, the fire’s planning operations section chief, said in a Facebook video update that hot, dry conditions were expected to last through Sunday. Officials expect the fire to spread in steep, rugged terrain on the fire’s south side.

As the McKinney Fire raged on, California Gov. Gavin Newsom declared a state of emergency. The proclamation gives Newsom more leeway in making decisions about emergency response and recovery efforts, as well as accessing federal aid.

California law enforcement knocked on doors in the towns of Yreka and Fort Jones to urge residents to get out and safely evacuate their livestock onto trailers. Automated calls were being sent to land phone lines as well because there were areas without cell phone service.