Thousands of Southern California electrical customers had their power cut Wednesday and more than 200,000 others faced the same prospect as utility companies sought to prevent wildfires as Santa Ana winds developed.

Red flag warnings were posted at late morning and were expected to remain in effect through much of Friday due to predicted strong gusts and very low relative humidity, the National Weather Service said.

Winds were expected to range between 35 and 55 mph before weakening Saturday. Officials were urging people who live in fire-prone areas to be ready to evacuate if necessary. Southern California Edison warned of possible power shut-offs as a precautionary measure.

Gusts to 75 mph were expected near and below Cajon Pass and near the coastal foothills of the Santa Ana Mountains.

“Fire danger will rapidly escalate during the night,” forecasters said.

The Santa Anas brought the prospect of public safety power shutoffs in high-risk areas to prevent wildfires from being sparked if the winds were to damage power equipment or blow debris into power lines.

Edison said power was cut to more than 8,000 customers in Los Angeles, Riverside and San Bernardino counties as of Wednesday night and shutoffs were possible for more than 170,000 customers in six counties.

San Diego Gas & Electric was considering shutting off electricity to more than 53,000 customers.

In North Hollywood, a tree crashed down on two vehicles parked in the 11600 block of Haynes Street, a Ford Focus and a Nissan pickup truck, late Wednesday night.

Forecasters also warned of a possible overnight hard freeze in the Antelope Valley north of Los Angeles.

Expect sunshine across our region. Highs will be in the mid-70s to lower-80s from the beaches to downtown Los Angeles, the 70s to around 80 in the San Fernando Valley, the 70s to lower-80s in the San Gabriel Valley, the mid-60s to around 70 in the Santa Clarita Valley and the upper-50s to mid-60s in the Antelope Valley.

Air quality will mainly be in the moderate range.