The Glass Fire, which began as a 20-acre brush fire near Deer Park, could spread further by winds that are expected throughout the day, Cal Fire said. The fire is 0% contained.
PT, Napa County spokeswoman Janet Upton said. The fire is burning near St. Helena, about 25 miles east of Santa Rosa. Cal Fire said the cause is under investigation.
Upton said about 660 homes -- or about 2,000 people -- have evacuated. St. Helena Hospital was evacuated out of an abundance of caution, the second time the hospital has evacuated this fire season.
Residents are heeding the warnings, said Napa County Sheriff's Office spokesman Henry Wofford.
"We activated the high-low siren on our vehicles because we knew we needed to get people out of there quickly," Wofford said. "When they hear that high-low siren coming from cars as we drove through their neighborhoods they know it's time to evacuate. The motto is, 'If I can hear it, it's time to go.'"
Craig Philpott posted photos and videos to his Twitter account that show the Glass Fire blazing red overnight and the fire's smoke choking the air on Sunday morning.
In California, five of the state's top 10 largest fires in recorded history, in terms of acreage, have occurred in 2020 and are still burning.