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 to much strain on the state's electrical system, possibly leading to rolling power outages, like those that occurred during high heat last month.
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An excessive heat warning issued by the National Weather Service will be in effect from 10 a.m. Friday until 8 p.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.
"Extreme heat will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities.'' according to an NWS statement.
"Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors,'' the NWS advised, adding 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.
SoCal Edison is asking customers to set their thermostats at 78 degrees - or if you won't be home, bump it up to 85.
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Woodland Hills, which experienced power outages for 24 hours during the last heat wave, is forecast to hit highs 117 degrees Sunday, according to the NWS.
The high heat is being attributed to high pressure, which is forecast to settle into the Great Basin area through the weekend.
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In anticipation of 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 Los Angeles 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.
"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. Dangerous heat'' is expected, it warned on its website.
The coronavirus pandemic is adding further complications to staying cool, with shopping malls and movie theaters closed. Local beaches are expected to be swamped, with the potential for crowds not following physical distancing protocols.
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Physicians are also warning people about the dangers of outdoor activity - or being indoors without air conditioning - during the extreme heat.
"The heat exhaustion, the heat stroke, these things can come on very suddenly," said Dr. Michael Daignault, an emergency physician with Providence St. Joseph Medical Center.
Cooling centers are open through the weekend in the cities of Los Angeles and Long Beach and in L.A. and Orange counties.
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.
City News Service contributed to this report.