Dangerous heat wave continues baking Southland

A Labour Day weekend heat wave in Southern California could set all-time records with the scorching heat escalating the risk of fires. (Photo by Frederic J. BROWN / AFP) (Photo by FREDERIC J. BROWN/AFP via Getty Images)

A historic heat wave took hold of the Southland on Saturday, bringing dangerous conditions through the Labor Day holiday and causing an increased danger of wildfires.  

As of Saturday evening, effective immediately, all trails in the Santa Monica Mountains will be closed through Labor Day, Malibu Search & Rescue says.

The agency says they responded to several heat-related rescues today, including one hiker who died.

They advise against hiking during the heat wave.

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Forecasters said some all-time temperature records could be set in some valley areas, and Woodland Hills broke its all-time record with a temperature of 117, according to the National Weather Service.

The previous record of 114 was set in 1955.  

Elsewhere, Van Nuys had reached 113 degrees by 2 p.m., while it was 114 in Calabasas, 111 in Santa Clarita, 109 in Pasadena, 108 in Burbank and 99 in downtown Los Angeles.  

Temperatures were also expected to rise sharply in Orange County, reaching as high as 113 in Anaheim on Saturday and Sunday and 113 and 114 in Fullerton, with a sharp decrease forecast for Monday.  

"The very hot conditions through Labor Day will bring an increased threat of large fire activity including fires with large vertical growth," the NWS tweeted.  

"These highs on Saturday and Sunday will be about 15-25 (degrees)above normal across the region," according to an NWS statement.

"Temps will become dangerously hot for most areas, even over the coastal plain away from the beaches Saturday and Sunday. This kind of heat can be life-threatening and people are urged to use common sense, keep hydrated and stay out of the heat and in air-conditioned locations as much as possible."  

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The high temperatures were sparking concerns about demand on the state's power grid as residents turn up their air conditioners.  

The California Independent System Operator, which manages the power grid, announced that a Flex Alert -- a call for voluntary conservation -- will be in effect from 3 to 9 p.m. Saturday through Monday.

Urging voluntary conservation is an effort to stave off too much strain on the state electrical system, possibly leading to rolling power outages, like those that occurred during high heat last month.  

An excessive heat warning issued by the NWS will be in effect until 8p.m. Monday in the San Gabriel and Santa Monica Mountains, Santa Catalina Island and the San Fernando, Santa Clarita, San Gabriel and Antelope valleys.

In Orange County, the warning will be in force in coastal areas from 10 a.m. Saturday until 8 p.m. Monday.  

Authorities advised that children, seniors and pets must never be left unattended in vehicles under any circumstances since temperatures can quickly turn lethal in the current conditions.  

Cooling centers will be open throughout Los Angeles and Orange counties:

They can be found at: https://ready.lacounty.gov/heat/  and www.211oc.org/resource-centers/extreme-heat-cooling-centers.html.  

Authorities noted that due to the coronavirus pandemic, cooling centers will be limited in capacity and restrictions will be in place, such as requiring face coverings.  

The high heat is being attributed to high pressure, which is forecast to settle into the Great Basin area through the weekend.  

In forecasting an increased fire danger, forecasters said they were mainly focusing on the dryness that will take hold in the region, partly because of the absence of monsoonal moisture. Forecasters said humidity levels will fall to single digits in interior areas of L.A. County.

But no red flag warnings indicating a high risk of wildfires are likely to be issued, principally because a key component of fire weather is missing -- strong winds, forecasters said.  

Red flag warnings were issued, however, in parts of Riverside and San Diego counties.  

The heat was expected to ease by about 10-12 degrees on Monday, but still remain above 100 degrees in many areas.