LOS ANGELES -- Southern California sizzled Friday in record-breaking heat from the desert to the sea, with widespread triple-digit highs and withering conditions stoking wildfires.

Officials urged people to take advantage of cooling centers in libraries and other facilities and to watch out for the elderly and very young, warning minor heat-related illnesses can worsen quickly.

Sidewalks and outdoor lunch tables were left to the blazing sun.

"There are no people," said Gloria Aguilar, 37, a food vendor in the Los Angeles piñata district. "Because it's too hot, and they want to stay inside the house. We sell more water than the food."

Firefighters worked in extreme temperatures as they battled outbreaks of wildfires, including a destructive blaze in the San Diego County community of Alpine and another spreading from a truck fire on Interstate 15 in Cajon Pass east of Los Angeles.

The heat was being produced by a "humongous" dome of high pressure spreading oppressive conditions into parts of Arizona, Nevada and Utah, the National Weather Service said.

"Today will be one for the record books," the Los Angeles region weather office said before sunrise -- and within a few hours records began to fall.

In downtown Los Angeles, it was only 10:15 a.m. when the mercury topped the July 6 mark of 94 degrees set in 1992 and kept on rising, hitting 100 before noon.

LA's Woodland Hills neighborhood was a record 115 degrees by early afternoon, just a few degrees behind the 119 punishing the aptly named community of Thermal in the low desert southeast of Palm Springs.

Southeast of Los Angeles in Orange County, Los Alamitos Race Course canceled daytime racing after two races because of the heat.

The offshore flow of air pushing back the normal moderating influence of the Pacific Ocean had produced startling early morning temperatures: At 3 a.m., it was 98 degrees in Gaviota on the Santa Barbara County coast about 125 miles west of Los Angeles, the weather service said.

While beaches offered relief from the furnace-like conditions, forecasters warned a lingering south swell from former Hurricane Fabio would continue to combine with a local northwest swell to produce dangerous rip currents and the possibility of sneaker waves.

Residents toughing it out in the valleys around Los Angeles and in the inland region to the east faced the possibility of unhealthy air quality. Air pollution regulators said the conditions were likely to produce an atmospheric inversion increasing ground-level ozone, which is linked to a host of respiratory troubles ranging from trouble breathing to asthma attacks.

The highest fire danger stretched from Los Angeles County westward into several counties up the coast where a north wind added another element to the mix of hot, dry air and parched vegetation. Elsewhere, the fire risk was characterized as elevated.

An additional threat was likely to develop by Sunday with the arrival of seasonal monsoonal moisture and the possibility of thunderstorms.

"Any lighting strike is going to be a concern," said Alex Tardy, a meteorologist with National Weather Service in San Diego.