SAN DIEGO -- The first Santa Ana wind event of the fall in the San Diego area elevated fire danger and other public-safety concerns in the county's mountains and valleys Thursday, with the conditions expected to linger through Friday evening.
In response to the potential hazards, the National Weather Service issued a "red flag" wildfire warning that went into effect at noon and was due to expire 6 p.m. Friday. The alert indicates a likelihood of "critical fire weather" stemming from extremely low humidity levels combined with gusty winds out of the east and northeast.
Cal Fire officials stressed the need for locals to take basic preventative steps, such as avoiding lawn-mowing during high winds; steering vehicles clear of extremely dry vegetation, where sparks might touch off a blaze; limiting campfires to designated places and looking out for suspicious behavior that could be arson-related.
The local threat level over the period was expected to be "moderate," according to the Santa Ana Wildfire Threat Index, meaning any wildland blazes that might erupt could be "difficult to control."
Temperatures will increase slightly through Saturday, when the winds are expected to be much weaker, according to forecasters.
In response to the wildfire warning, San Diego Gas & Electric this week alerted about 30,000 of its customers that it may suspend their electrical service at times over the period to reduce combustion hazards posed by power lines.
Based on improved weather conditions, however, SDG&E lowered its forecast Thursday afternoon of how many customers could be affected by pre-emptive power-downs to roughly 18,000 homes and businesses -- 40% fewer than the original estimate.
SDG&E advised that it plans to provide updated notifications to customers within 24 hours of an anticipated power-down, and again within one to four hours of a shut-off, if possible.
The utility advises those who have received the notification to be prepared by making sure they have such emergency supplies as water, food, flashlights, extra batteries and cellphone battery packs.
Should any precautionary power shut-off last more than 24 hours, the utility plans to open temporary aid centers where customers can get water and snacks, charge their cellphones and get updates.