By Dan Whitcomb and Scott DiSavino
LOS ANGELES (Reuters) -Much of the western United States baked for a third day on Wednesday under a punishing heat wave that has set temperature records, prompted health warnings and strained power grids.
Although a shift in the weather has provided some relief to northern states, including Montana and Idaho, the worst was still to come for California and parts of the Southwest, National Weather Service meteorologist Eric Schoening said.
"We're in a long-duration heat wave across the Western U.S.," Schoening said. "Across the desert Southwest extending into California we're still ramping up the temperatures throughout the rest of the week."
Salt Lake City, Utah, on Tuesday tied its all-time high temperature since record-keeping began in 1894, at 107 degrees Fahrenheit (42 degrees Celsius). Phoenix tied a record for this date at 115 degrees and Needles, California, in the Mojave Desert near the border of both Nevada and Arizona, hit 121 degrees, also tying a daily record.
The National Weather Service has issued excessive heat warnings across the U.S. West, warning that such conditions can be dangerous, even fatal. No deaths had been reported from the brutally hot weather as of Wednesday afternoon.
"Try not to spend too much time outside during the hottest part of the day. Wear light clothing, stay hydrated," Schoening said, adding that residents should be "keeping an eye on pets, checking on the elderly, not leaving anyone, including kids or pets in hot cars."
WILDFIRE DANGERS
The weather service also issued red flag warnings of high fire danger in Arizona, California, Nevada and Utah. Major wildfires were burning in Colorado and Arizona.
Wildfires scorched more than 6,500 square miles (17,000 square km) of land in 2020, destroying hundreds of Californian homes during a particularly fierce fire season.
The unusually severe late-spring heat wave was the result of a high-pressure ridge that built over southwestern deserts, weather service meteorologists say, and could not be blamed directly on global warming.
"But studies show that as the climate changes and it gets warmer, we will see more of these anomalous events over time," Schoening said.
The brutal heat triggered a surge in electricity demand as residents cranked up air conditioners and fans. Texas and California, the two most populous U.S. states, urged energy conservation.
California's grid operator issued a "Flex (NASDAQ:FLEX) Alert" for Thursday evening, telling residents to turn off unneeded appliances and office equipment between 5 p.m. and 10 p.m. and thermostats higher.
California and Texas both imposed rolling blackouts over the last year to avoid a power system collapse, California due to the heat in August 2020 and Texas in February 2021 after a deep freeze that left millions without heat.
Much of the U.S. Southwest is also in the grip of a drought that has cut hydropower supplies, leaving rivers running dry and prompting ranchers to sell livestock.
The Electric Reliability Council of Texas (ERCOT), which operates most of the state's power system, projected demand would break the June record, set on Monday, in the coming days.