The fire began on Monday just before 7 a.m. PT east of Irvine, a city about 40 miles south of Los Angeles. Powerful Santa Ana winds and red flag conditions conducive to fanning wildfires helped the blaze quadruple in size throughout the day, according to CNN. The winds were so strong on Monday—clocking in at up to 60 miles per hour—that officials could not use aerial crews.

Allen Schaben, a photographer for the Los Angeles Times, filmed a video showing the gusts.

The Silverado Fire has burned through 11,199 acres and is only 5 percent contained, according to a Tuesday morning update from the Orange County Fire Authority (OCFA), which is managing the blaze.

While there haven’t been any reported structure losses yet, around 91,000 people in various Orange County neighborhoods have been forced to evacuate. Firefighters in the Foothill Ranch area are focused on keeping the blaze confined to the hill so it doesn’t reach any of the homes below, according to KCBS-TV.

Schaben filmed another video on Monday of firefighter Raymond Vasquez as he tried to beat back the advancing flames.

About 750 firefighters are working to put out the Silverado Fire, KTLA reported. Two OCFA firefighters were severely injured Monday afternoon. They suffered second- and third-degree burns, which left them hospitalized and placed on ventilators, according to KCBS-TV.

Southern California Edison (SCE), an electricity supply company, said that a power line could have played a role in causing the wildfire, according to a report filed with the California Public Utilities Commission. The initial safety incident report found overhead electrical facilities in the area where officials believe the fire started, but noted there was no activity on the circuit, CNN reported.

“[It] appears that a lashing wire attached to a telecommunications line may have contacted SCE’s power line above it, possibly starting the fire,” SCE Southern California Edison spokesman Chris Abel told CNN.

Twitter user Matt Bragman, who lives in nearby Huntington Beach, shared a photo captured by KABC-TV showing the Silverado Fire’s proximity to Irvine.

In an update Tuesday morning, the OCFA’s public information account tweeted that the weather is expected to improve in the area, with wind speed lowering drastically to a predicted 10 miles per hour, with gusts at 20 miles per hour.

While red flag conditions were expected until around 2 p.m., they were anticipated to eventually taper out and allow aircraft usage, OCFA tweeted.

“This is a tough fire,” OCFA Chief Brian Fennessy said Monday. “We’re experiencing very high winds, very low humidity…. Any time winds are that bad you can’t fly, and that certainly has an impact on both hand crews and bulldozers and firefighters at the end of those hose lines.”

A photographer based in Carlsbad captured a group of firefighters standing in front of the Silverado Fire.

Officials in Orange County are also battling the Blue Ridge Fire, which is burning in Corona, about 10 miles north of the Silverado Fire. It is approximately 8,000 acres and remains zero percent contained. One home was damaged in Yorba Linda, according to an OCFA update.

The latest wildfires add to an extremely busy fire season in the state. The California Department of Forestry and Fire Protection has reported at least 8,000 fire incidents this year and a record 4 million acres burned.