City officials are urging residents who live in Berkeley hillsides to stay elsewhere during extreme fire weather events.

“During ‘Extreme Fire Weather’ — rare periods of extremely low humidity and high winds defined by Berkeley Fire Department — residents living in hillside fire zones are advised to make plans to stay elsewhere,” a statement from the city reads.

City officials are encouraging these residents to sign up for emergency notifications, look up their evacuation zone on Zonehaven and to make plans to leave when warnings are issued.

A graphic shows the relationship between low humidity and high winds in contributing to “Extreme Fire Weather” events such as those that spawned the 1991 Oakland/Berkeley Hills firestorm in addition to most of California’s major wildfires. (Image courtesy of city of Berkeley)

The areas of the city a greatest risk, officials said, are in fire zones 2 and 3 that are close to regional parklands in the hills on the eastern edge of the city, just north of state Highway 24 and stretching to the northern and eastern border with Contra Costa County.

City officials said the evolving fire threat demands a different type of response.

“Severe fire weather conditions are now more common and as a result, so are catastrophic wind-driven fires,” according to the news release.

The Berkeley Fire Department has identified the types of very dry, windy conditions that create “Extreme Fire Weather” and compiled a chart and a video series to help residents understand.