With the autumn season’s first significant Santa Ana wind event forecast this week, state and local officials Tuesday advised Riverside County residents to be prepared for wildfires and do what they can to prevent them.
The National Weather Service issued a Red Flag Warning, meaning “critical fire weather” stemming from extremely low relative humidity is anticipated for the duration of the easterly winds.
The warning is in effect from 3 a.m. Thursday to 6 p.m. Friday throughout California. The Weather Service said a ridge of high pressure will begin to settle over the Great Basin in Nevada and Utah mid-week, churning up offshore winds that will be particularly fierce in mountains and passes.
Winds of 20-30 mph are likely to be the norm in the Inland Empire, with isolated gusts as high as 70 mph in narrow passages, such as the Banning Pass, forecasters said.
“With some of the most destructive and deadliest fires occurring October through December, we need Californians to not be complacent,” Cal Fire Chief Thom Porter said. “Wind-driven fires move fast, and residents need to be ready to evacuate at a moment’s notice in the event of a wildfire. We have increased our staffing but need the public to remain vigilant. It is important to follow evacuation orders and leave early as fires move very fast under these conditions.”
Porter stressed the need for people to take basic preventative steps, such as not mowing lawns during high winds, not driving vehicles over extremely dry vegetation, where sparks or hot engine components might touch off a blaze, limiting campfires to designated places and being on the lookout for suspicious behavior that could be arson-related.
Caltrans District 8, which serves the inland region, issued a statement warning motorists that light signals could go out if utilities implement “public safety power shutoffs,” which are permitted by the California Public Utility Commission.
The shutoffs, also known as “de-energization,” are permissible during high fire danger to prevent electricity lines from arcing, or transformers from throwing sparks and igniting fires, particularly in places not easily accessible to firefighters.
Southern California Edison, which serves large swaths of Riverside County, has a policy of generally trying to notify customers two days in advance of a prospective shutoff.
“Caltrans is advising motorists that (traffic) signalization on state routes throughout Riverside and San Bernardino counties may be affected during the power outages,” according to an agency statement. “The signals will continue to cycle regularly for approximately three hours after the outage and will then cycle to `red-flash’ for another three to six hours. If the outage remains in place for more than six hours, the signals will then go to `blackout’ mode.”
Officials said flashing and blacked out traffic signals must be treated as stop signs, with the usual right-of-way and yielding protocols in place.
The winds are predicted to dissipate Friday night.
Daytime high temperatures in the Riverside metropolitan area and Coachella Valley will hover in low 80s during the latter part of the week, forecasters said.