Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. California Labor Day Weekend Brings Heat, Fire, Virus Fears Associated Press LOS ANGELES - Excessive heat warnings began going into effect in California on Friday as forecasters predicted that high pressure building over the western U.S. would send temperatures soaring to dangerous levels during the long Labor Day weekend. Initial warnings issued for Southern California's valleys, mountains and deserts were expected to expand out to the coast and into Northern California by Saturday. A "brutally hot" four days are in store, the National Weather Service wrote. Downtown Los Angeles was forecast to reach 107 degrees (41.6 Celsius) on Saturday and 108 on Sunday (42.2 Celsius). Napa in the wine country could reach 113 degrees (45 Celsius), and Palm Springs could reach 120 (48.8 Celsius). Fleeing to beaches, mountains The forecasts brought calls for Californians to conserve electricity and raised concerns that people flocking to beaches or mountains to escape the heat could spread the coronavirus. The rush was already on in the popular San Bernardino National Forest east of Los Angeles, where high elevations and lakes offer respite. "I got a note that most of the campgrounds in the San Bernardino mountain range are already full and I expect them to be completely full within the hour," forest spokesman Zach Behrens said at midmorning Friday. The California Independent System Operator, which runs California's power grid, issued a "Flex Alert" for the hours of 3 p.m. to 9 p.m. Saturday through Monday, asking people to conserve power by not using washing machines and other appliances during the period and keeping their air conditioners at 78 degrees (25.5 Celsius) or above. "We're not forecasting any blackouts" at the moment because of the heat, but the power system could be strained by unforeseen problems, such as a fire that disrupts a power line, Cal ISO Operations Vice President Eric Schmitt said. Cal ISO also ordered power generators to postpone routine maintenance and restore any out-of-service transmission lines. .