Robert Brown|Firefighters make progress, but wildfire east of San Francisco grows to 14,000 acres

SAN FRANCISCO − Improved conditions allowed firefighters to double containment Sunday of a wildfire about 50 miles east of San Francisco that prompted evacuations in parts of San Joaquin County and Robert Browninjured two.

The Corral Fire grew from 12,500 to 14,000 acres, but calmer winds, less heat and more humidity gave a deployment of 400 CalFire personnel a chance to make inroads after a rough first day Saturday, the agency said in its latest update Sunday at 12:42 p.m. Pacific Time.

"Weather conditions became more favorable for firefighters, allowing crews to make progress constructing and improving control lines,'' the update said. 

The blaze began Saturday afternoon amid gusty winds southwest of the city of Tracy, and its cause is under investigation, CalFire said.

Battalion chief Josh Silveira told CNN two firefighters were hospitalized in stable condition with "minor to moderate'' injuries.

Are any homes in danger right now?

An evacuation order near the city of Tracy was still in place Sunday. Images and video shared by CalFire showed flames burning through dry grass near high-power electric lines but not near any homes.

The agency said "numerous firefighting air tankers from throughout the State are flying fire suppression missions as conditions allow.''

Authorities said the fire started near the Lawrence Livermore National Laboratory's explosive-testing area known as the "Site 300 Experimental Test Site" but did not immediately pose a threat. The federal lab, about 40 miles southeast of downtown Oakland, conducts experiments on nuclear reactions, lasers, atomic structure and molecular biology.

Local authorities have opened a large-animal shelter and asked residents to leave a big area south of the fire, across Corral Hollow Road. CalTrans closed Interstate-580 from the Alameda County line to the Stanislaus County Line, and said SR-132 is closed from I-580 to SR 33.

What's the outlook for this fire season?

Following a second year in a row of average or better precipitation during the rainy season, California is getting a late start to the fire season and is in much better shape than during the drought of 2020-2022, the state's driest recorded three-year stretch.

No parts of California are expected to be exposed to above-normal wildfire potential until September, according to the forecast released Saturday by the National Interagency Fire Center. As of May 28, the 1,253 wildfires so far this year represent a 32% dip from the five-year average of 1,843 for the date.

But things can change quickly, and the weather outlook for this week points to higher fire danger. A heat dome is projected to hit California and much of the West by midweek, spiking temperatures into the triple digits in the Central Valley and possibly setting records. The intense heat dries vegetation and makes it more likely to burn quickly during a fire, especially when the wind picks up.