Hundreds of lightning-sparked wildfires have turned the air of Northern California into an unhealthy stew of smoke and ash, forcing the cancellation of athletic events and other outdoor activities.
Health advisories urging residents to stay indoors to limit exposure to the smoky air were issued Saturday from Bakersfield north to Redding, a distance of almost 450 miles.
Air pollution readings in the region are two to 10 times the federal standard for clean air, said Dimitri Stanich, spokesman for the California Air Resources Board.
Some areas are experiencing the worst air quality on record, with the smoke hanging down to the ground like a fog.
Air-quality agencies are especially concerned about small-particle pollution. The tiniest particles can penetrate past the body's immune defenses, traveling deep into the lungs and the bloodstream.
“When you have it on the scale we are seeing now, it is very dangerous to the general public health,” Stanich said.
Changing weather brought smoke-clearing breezes and brief relief to some areas Saturday, but it could also bring lightning storms similar to the ones that ignited fires across Northern California a week ago.
Thunderstorms could strike anywhere in the northern Sierra Nevada or the northern Central Valley on Saturday night, said National Weather Service forecaster Johnnie Powell in Sacramento.
The thunderstorms could also bring a small amount of much-needed rain, he said. The front was expected to pass by today, setting up a second week of abysmal air quality.
The renewed threat of dry lightning and stiffer breezes that could stir the wildfires led fire officials to declare a “red flag warning” – meaning the most extreme fire danger – until 5a.m. Monday for Northern California.
On Saturday, President Bush issued an emergency declaration for California and ordered federal agencies to assist in firefighting efforts in many areas.
More than 17,000 firefighters were fighting more than 1,000 fires Saturday, said state emergency services spokesman Kelly Huston.
“The summer has just begun, and fire conditions will only get tougher,” Ruben Grijalva, director of the California Department of Forestry and Fire Protection, warned in a weekly radio address on behalf of Gov. Arnold Schwarzenegger.
The fires have destroyed 47 structures and injured 85 people and continue to threaten nearly 10,000 homes, businesses and buildings, according to his department.