‘Heat dome’ could keep the West sizzling
Excessive heat is fueling wildfires across six states
The record-breaking heat across much of the West eased somewhat Monday, but a “heat dome” means temperatures could remain well above average all week, forecasters said.
The weather setup is similar to what the region saw two weeks ago, when deadly heat across the Pacific Northwest and western Canada broke records and fueled devastating wildfires.
“This time, the core of the high pressure and heat has been anchored farther to the south and has allowed excessive heat to build up across the region,” AccuWeather senior meteorologist Adam Douty said.
The National Weather Service warned Americans facing the oppressive heat to stay hydrated, seek shade and not leave children or pets alone in vehicles.
As of Monday afternoon, more than 13 million Americans in the West were under an excessive heat warning, the weather service said.
The heat is straining power grids and fueling wildfires across almost 500 square miles – the size of Los Angeles – in six Western states.
In California, wildfire season is outpacing last year’s – the worst on record – according to the Los Angles Times, based on data from the California Department of Forestry and Fire Protection.
In Oregon, the Bootleg Fire was the biggest, burning across more than 220 square miles and 0% contained as of Monday.
In California, the Beckwourth Complex Fire had burned more than 140 square miles, the state’s largest fire this year. It was 23% contained Monday.
Residents were asked to limit power consumption after fire knocked out interstate power lines, jeopardizing up to 5,500 megawatts of electricity.
Heat warnings have been in effect for almost a week across much of the Southwest. Douty said that although the peak of the heat has passed for Death Valley and Las Vegas, temperatures are forecast to remain 5 to 15 degrees above normal through much of the week.
Daily records were tied or broken over the weekend across California, Nevada and Arizona, and extreme heat extended into Idaho and the interior parts of the Pacific Northwest.
AccuWeather expected the temperature in Death Valley to reach 127 degrees Monday afternoon, just shy of the area’s daily record high of 129. The world record high is 134 degrees, which was set in Death Valley in 1913.
St. George, Utah, reportedly reached 117 degrees Friday. If confirmed, that would tie for the hottest day on record for the state.
Las Vegas set a daily record-high temperature Friday of 116, then broke a different record Sunday.
“Las Vegas went from record-breaking heat yesterday, to record-breaking rainfall today,” the National Weather Service in Las Vegas tweeted late Sunday, saying the 0.1 inch of rain measured at McCarran International Airport is the most rain on any July 11 since records began in 1937.
Blame the heat dome. A heat dome is the result of a strong change in ocean temperatures from west to east in the tropical Pacific Ocean during the preceding winter, according to the National Ocean Service. The warm air coming from the west part of the Pacific Ocean then gets trapped in the jet stream as it approaches land.
When that hot air arrives over land, the atmosphere traps the hot air as if a lid was put on it. Winds can move the heat dome around; hence it is also referred to as a heat wave.
Heat and wind can be a deadly combination for wildfires. Two Arizona firefighters died after a plane responding to a wildfire crashed Saturday afternoon, according to the federal Bureau of Land Management. The Cedar Story Basin Fire was more than 700 acres and was 0% contained Monday afternoon.
Late Saturday in California, flames from the Beckwourth fire jumped U.S. 395, which was closed near the small town of Doyle in Lassen County. The lanes reopened Sunday – with a strong warning to motorists.
“Do not stop and take pictures,” the fire’s Operations Section Chief Jake Cagle said. “You are going to impede our operations if you stop and look at what’s going on.”
In Washington, a wildfire grew to almost 60 square miles in the Umatilla National Forest. In Idaho, Gov. Brad Little mobilized the National Guard to help fight fires sparked after lightning storms engulfed the drought-stricken region.
All this after last month checked out as the hottest June on record, according to a report released Friday by the National Oceanic and Atmospheric Administration. With the heat comes drought. Extreme to exceptional drought conditions affect vast swaths of California, Nevada and Arizona, according to the U.S. Drought Monitor.