Firefighters in the western US were on Sunday struggling to contain wildfires as the region was struck by a heatwave that has caused record temperatures.
Large fires are burning across a dozen western states, including Alaska, according to the US National Interagency Fire Centre.
Nearly 10,000 firefighters and support staff are tackling 57 blazes across 15 states nationally, the centre said on Saturday.
Communities have been told to evacuate their homes and two firefighters have died in an aircraft crash.
A wildfire raging uncontrollably across southern Oregon has knocked out electrical lines and hit power supplies in California and Nevada.
Sweltering conditions have struck much of the Pacific coastline and as far inland as the western edge of the Rocky Mountains this weekend, covering an area that is home to more than 30 million people.
Las Vegas matched its record of 47.2 Celsius on Saturday.
California’s Death Valley National Park, about 180km west of Las Vegas, registered a high of 54 Celsius on Friday.
Forecasters issued heat warnings for Las Vegas, Phoenix and San Jose, the Silicon Valley technology hub south of San Francisco.
"Over 30 million people remain under either excessive heat warnings or heat advisories," the National Weather Service said in a weekend alert.
The weekend's hot weather follows another heatwave that struck the western US and Canada last month.
The Canadian province of British Columbia then recorded all-time high temperatures for three days in a row.
The death toll is not yet known but is thought to run into the hundreds.
It was the hottest June on record in North America, according to European Union climate scientists.
Emissions of heat-trapping gases have driven global temperatures up, stoking fierce storms, extreme heatwaves, droughts and wildfires.
The last six years, including 2020, have been the six warmest on record.