Winds spread a brush fire 156 acres on the south Santa Barbara County coast early Thursday amid a spell of hot and dry weather.

The fire erupted on a ridge near Hollister Ranch shortly after 2 a.m. as “significant” offshore winds swept the area, said county fire Capt. Daniel Bertucelli.

Containment was estimated at 50% by later afternoon. Officials earlier estimated the fire spanned about 200 acres, but later said it was more than 150 acres in size.

Voluntary evacuations of several houses on the ranch were requested.

A water-dropping helicopter aided about 120 firefighters battling the flames about 35 miles (56 kilometers) west of the city of Santa Barbara.

The cause of the fire was under investigation.

The National Weather Service said the extended period of gusty northerly winds was slowly coming to an end after howling overnight. Gusts in the Montecito Hills just east of Santa Barbara reached up to 67 mph (108 kph).

A heat advisory for the area and other parts of Southern California was expected to remain in effect until 9 p.m. Thursday.