A giant cluster of rapidly spreading wildfires in Northern California has torn through more than 1,500 homes and businesses and led to the deaths of 15 people on Monday and Tuesday in one of the most destructive wildfire events in the state’s history. More deaths and destruction are expected.

The fires whipped through the arid wine country north of San Francisco, frenzied by high-speed hot and dry winds. According to the Washington Post, the at least 15 fires in nine counties are not predicted to succumb to the firefighters’ efforts soon, and strong winds that can exceed 50 miles per hour are likely to fuel their spread in the next few days. According to the Associated Press, the cause of the fires is not known, and they are not connected to one another.

Sonoma County officials said they had received more than 100 calls to the county’s missing persons hotline, and 20,000 people have been forced to evacuate their homes. More than 100 people have been injured, mostly through smoke inhalation. According to the Chicago Tribune, the fires together burned more than 100,000 acres in California on Monday. Most of the deaths, according to the Los Angeles Times, occurred in Sonoma County, where a smaller but faster-moving fire is raging.

One of the fires, called the Tubbs Fire, burned 27,000 acres of the Santa Rosa area, according to Cal Fire, the state agency dealing with fire protection. Another, the Atlas Fire, consumed 25,000. In Santa Rosa, according to USA Today, entire neighborhoods, a hotel, big-box stores, and a trailer park have all burned down, and two hospitals have been forced to evacuate their patients.

California Gov. Jerry Brown initially declared a state of emergency in Napa, Sonoma, Yuba, and later added Butte, Lake, Mendocino, Nevada, and Orange counties. The largest fires have raged in Napa and Sonoma counties, where reports have depicted vineyards and popular tourist spots as charred and wineries as heaps of debris.

According to the Associated Press, Napa and Sonoma counties were finishing the harvest of wine grapes at the time of the fires. Most wineries were reported as closed because of evacuations and power outages. The destruction of the vineyards might have significant economic repercussions for the wine industry and California in general.

The National Guard has been sent to help fight the fires, and Cal Fire sent the world’s largest firefighting air tanker to make drops on the fire, according to USA Today.

The fire captain for Cal Fire told reporters that the rapid and powerful bloom of fires was likely linked to a warming climate, according to the Guardian. The fire seasons have been longer, she said, and fires “are burning more intensely.”

Update, Oct. 10, 2017, at 12:10 p.m.: This post has been updated to include new numbers of fatalities and total acres burned.

Correction, Oct. 10, 2017, at 12:15 p.m.: This post incorrectly gave the number of homes and businesses burned as 2,000. At the time, 1,500 homes and businesses were being reported as burned.

Update, Oct. 10, at 1:26 p.m.: This post has been updated to include new numbers of fatalities.

Update, Oct. 10, at 3:45 p.m.: This post has been updated to include new numbers of fatalities.