(KRON) Four fires burning in the North Bay have merged into a single massive blaze burning in Napa and Sonoma counties.
The Partrick, the Nuns, the Norrbom and the Adobe fires are now one.
The Pressley fire is also close to merging with the four others.
Firefighters gained some ground on a blaze burning in the heart of California’s wine country but face another tough day ahead with low humidity and high winds expected to return.
The death toll climbed to 31 on Thursday, making it the deadliest week of wildfires in California history.
Hundreds more are injured or missing. In areas where they were able, cadaver dogs were sniffing through the ashes.
Smoke from wildfires is creating the worst air quality in the San Francisco Bay Area on record, sending people to the emergency rooms, forcing schools to close and people to wear masks when they step outside.
The region has endured several days of choking smoke since the fires began Sunday night destroying some 3,500 homes and businesses.
Regulators say the air quality in most of the region has sank to the same unhealthy level as some of China’s smog-choked cities.
With winds expected to continue blowing smoke from the fires to populated areas this weekend, many schools decided to close Friday.
Organizers canceled weekend events, such as a half marathon in San Francisco, and sports teams such as the Oakland Raiders are monitoring the air quality as they prepare to host games.
- INTERACTIVE MAP: SEE IF YOUR SANTA ROSA HOME SURVIVED THE FIRE
- SONOMA COUNTY FIRE VICTIMS IDENTIFIED
- COMPLETE LIST OF AREAS UNDER MANDATORY EVACUATION
- INTERACTIVE FIRE MAPS
- WINERIES DAMAGED BY NORTH BAY WILDFIRES
- LIST OF NORTH BAY FIRE RESOURCES
- NORTH BAY FIRES: HOW TO HELP
- WATCH KRON4 NEWS LIVE