SDG&E notified nearly 55,000 of its customers Sunday that their power might be temporarily turned off Monday or Tuesday to help minimize the risk of wildfires when the next round of Santa Ana winds begins whipping across much of San Diego County.
Most of the customers are located east of Interstate 15. But notices also went to people in parts of San Diego, and the outages could spread to other parts of the county.
The National Weather Service says a red flag fire weather warning will be in effect from 4 p.m. Monday to 6 p.m. Wednesday in the eastern half of the county. Forecasters said early Monday that the most intense winds could occur on Wednesday, a day later than expected.
Some of the winds could follow the mountain-to-coast corridor that spread the devastating Witch Creek fire in October 2007, the National Weather Service said. The roughly 100,000-acre blaze was largely responsible for destroying more than 1,100 homes and, at one point, appeared headed directly for San Diego.
The Santa Anas will begin to gain strength locally on Monday night and will peak on Tuesday when winds gust 40 mph to 50 mph in many inland areas and 20 mph to 30 mph at some spots along the coast. The relative humidity will fall below 20% from Borrego Springs to Oceanside and San Diego.
“This is going to be another long duration event because it won’t fully subside until Wednesday,” said Brian D’Agostino, vice president of wildfire and climate science at SDG&E.
“The state of the (vegetation) is very concerning because it is so dry, especially above the 2,000-foot level.”
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San Diego International Airport has recorded only 0.16 inches of rain since July 1. That’s close to 4 inches below average. A low-pressure system offshore could spin some moisture into the county on Tuesday. But forecasters said it would do little to nothing to tamp down the risk of wildfires.
The incoming winds will largely arrive from the east and have a fairly clearly path to the ocean. Some winds are expected to flow along a path that cuts through Lake Hodges, Olivenhain, Rancho San Fe en route to Encinitas, Solana Beach and Del Mar — a route similar to the one involved in the Witch Creek fire. A second corridor could funnel winds through Valley Center and Fallbrook all the way to Oceanside and Camp Pendleton.
“The only natural mechanism for starting wildfires is lightning, and we won’t be having that,” said Phil Gonsalves, a weather service forecaster.
“Almost all wildfires are man-made — something that’s controllable by humans. People need to aware, alert and careful about what could happen. And people should that a lot of fires that start in the backcountry — like the 2003 Cedar Creek fire — burn west toward the coast.”
Late Monday afternoon, SDG&E warned that customers should be prepared for prolonged high winds through Thursday.
“The extreme dry conditions in conjunction with the winds have contributed to this prolonged and dynamic event,” the utility said in a statement.
Union-Tribune energy reporter Rob Nikolewski contributed to this article.
