The Berkeley Fire Department is advising residents in the Berkeley Hills neighborhood to have a plan ready to evacuate and stay elsewhere in the event the department designates “extreme fire weather,” which is more severe than a red flag warning.

The guidance from the fire department was issued last week. Residents living in Berkeley Fire Zones 2 and 3 are particularly encouraged to make plans to stay away from or be prepared to leave their homes when the fire department identifies extreme fire weather.

Extreme fire weather occurs when conditions are very dry and windy, causing heightened risk of the ability of a fire to spread rapidly, according to the fire department.

Such conditions are rare, with the last extreme fire weather recorded in the area in 2020. That year, according to the department, there were 25 red flag warnings issued by the National Weather Service identifying heightened fire risk, but only two days of extreme fire conditions.

The fire department is advising residents to sign up for Alameda County’s unified “AC alert” system, which will be used to declare extreme fire weather.