Updated: 8:05 a.m. May 7
First discovered: 43 hours ago, 12:53 p.m. May 5
Initial location: Putah Creek Road/Olive School Lane, Winters in Solano County, Calif.
Fire unit: Cal Fire Sonoma-Lake-Napa Unit
Fire type: Wildfire
Fire name: Putah Fire
Putah Fire initially started 12:53 p.m. May 5 in Solano County.
It has burned 16.8 acres after being active for 43 hours. By Wednesday morning, a crew of 70 firefighters has achieved full containment of the blaze. The cause of it remains under investigation.
Firefighting efforts included 11 engines, four water tenders, one helicopter, one dozer and one hand crew. According to Cal Fire, “Numerous firefighting air tankers from throughout the State are flying fire suppression missions as conditions allow.”
Cal Fire status update
Situation Summary
The Putah Fire started early afternoon on a Monday during Wildfire Preparedness Week. The Vacaville Fire Protection District and Winters Fire Department were first on scene and reported that the fire was 5-6 acres upon arrival, burning in grass at a rapid rate of spread. Temperatures that afternoon were 81 degrees with a relative humidity of 16 percent and winds blowing from the north at 23 mph with gusts up to 33 mph.
CAL FIRE responded with five engines, one handcrew, a dozer and a helicopter with its Boggs Mountain Helitack Crew. CAL FIRE and the Vacaville Fire Protection District went into Unified Command on the fire.
The gusty winds aided in the spread of the fire, which was burning predominately in grass, up a hillside with one structure was threatened. Short-range spotting was observed, but crews were able to get around the fire fairly quickly and had its forward progress stopped by 2:14 p.m.
The fire ended up burning 16.8 acres. It was the first fire to exceed 10 acres in the Sonoma-Lake-Napa Unit for the 2025 fire year.
Combining all agencies, there were 11 engines, four water tenders, one crew, one dozer, one helicopter and 70 total personnel on the fire.
This corridor of Solano County is no stranger to early May grass fires. Back in 2022 there were two fires in close proximity to the Putah Fire. On May 3, 2022 at nearby Allendale Road south of Winters, there was the 95-acre Winters Fire. Later on May 21 that year, there was also a 135-acre fire off Pleasants Valley Road.
Fire containment
What does 100% containment mean?
Note that full containment doesn’t mean the fire is completely out. In this case, it means that firefighters have managed to get a line completely around the wildfire’s perimeter and it is now stopped from spreading. A fully contained wildfire may continue to burn within the containment perimeter but is not likely to spread.
However, there’s a significant difference between containing and controlling a wildfire. After the fire is fully contained, the next step is to control it. Controlling a fire means ensuring that the fire can’t spread or cross the containment line.
Containment is part of a larger plan for managing a wildfire. It is normally expressed as a percentage and it refers to how much of the fire perimeter has been surrounded/enclosed by a control line that firefighters create. The containment percentage indicates a certain level of control, but it doesn’t always correlate to safety level. Also, it’s important to note that containment doesn’t mean a fire is out.
How is containment measured?
The incident’s central command constantly receives progress reports from firefighters on the ground. As the fireline is constructed, inspected or reinforced, mappers record those details to adjust the containment percentage. The percentage tells the public how much of the fire perimeter is believed to not go beyond the control lines.
Source: Cal Fire