Update: Red flag warning issued for the Berkeley and Oakland hills through Monday evening, a rarity for December

Update, Dec. 7, 11:30 a.m.: The National Weather Service has extended the red flag warning for the East Bay hills and interior valley until 5 p.m. It originally was expected to last until 11 a.m.

Gusty winds and dry conditions are prompting the National Weather Service to issue a red flag warning for the Berkeley and Oakland hills from 11 p.m. to 11 a.m. on Monday, Dec. 7.

Winds could reach 15 to 25 mph with gusts up to 45 mph in higher locations and local gusts of up to 60 mph, according to the NWS.

The city of Berkeley sent out an email warning residents:

“Hills residents should prepare for a high fire danger warning starting at 11 p.m. on Sunday, December 6 by signing up for alerts, reviewing evacuation routes, packing or refreshing “go bags,” and parking off-street when possible.

This National Weather Service “Red Flag” warning, which is scheduled to end at 11 am Monday, December 7, means that people should use extreme caution when operating BBQs, power equipment, or other heat sources such as idling cars. Fires that start during Red Flag Warnings can spread rapidly due to high winds and dry vegetation. Remember that fireworks are always completely forbidden in Berkeley and the surrounding areas.”

A red flag alert in December is highly unusual but reflects the fact that there has been very little rain this fall. The high winds are coming from a trough of low pressure in Nevada that is generating warm, dry winds blowing toward the ocean, according to the Mercury News. They are known as the Diablo winds.