California’s largest wildfire grows to 70,000 acres

California’s largest wildfire of the year grew to an estimated 70,801 acres Friday, producing smoke that has affected millions of residents across the southern part of the state.

The Madre Fire in San Luis Obispo County erupted early Wednesday afternoon near the small town of New Cuyama along Highway 166 on the Carrizo Plain, according to Cal Fire.

Fueled by strong winds, the blaze quickly expanded to nearly 53,000 acres by Thursday afternoon, and had scorched roughly 82 square miles of dry brush by Friday afternoon, prompting evacuations in both San Luis Obispo and Santa Barbara counties.

Fifty structures were threatened, with containment at 10%, incident commanders said.

More than 600 firefighting personnel were battling the fire on the ground and from the air, using seven air tankers and two helicopters. No injuries had been reported.

The cause of the fire remained under investigation.

A temporary evacuation shelter was established at the California Valley Community Services District facility at 13080 Soda Lake Road in Santa Margarita.

Smoke from the fire has drifted south and east into metropolitan Los Angeles, prompting health officials to issue an air quality alert for areas including the Santa Clarita and San Gabriel valleys, as well as the San Bernardino Mountains.

“(Air pollution) levels due to Independence Day fireworks are also expected to reach Unhealthy for Sensitive Groups or higher,” the South Coast Air Quality Management District said in an advisory, “with the Air Pollution Index expected to reach hazardous levels at times on Friday and Saturday in large parts of Los Angeles and Orange counties and the Inland Empire.”

The AQMD offered the following tips for residents in smoke-affected areas:

• Limit exposure by staying indoors with windows and doors closed, or seek alternate shelter.
• Avoid vigorous physical activity.
• Run air conditioning and/or an air purifier. Avoid using swamp coolers or whole-house fans that bring in outside air.
• Avoid burning wood in fireplaces or fire pits, and minimize indoor air pollution from candles, incense, pan-frying and grilling.
• If you must go outside, a properly fitted N95 or P100 respirator may offer some protection.