Lake Oroville, California: There is a drought emergency in many regions
Photo: AUDE GUERRUCCI / REUTERS
Experts speak of a weather emergency: Almost 50 million people in the southwestern United States are threatened by an extreme heat wave.
Record temperatures have brought the power supply to the brink of collapse.
"It's an apocalyptic atmosphere, with this record heat and the smoke from the wildfires wafting through the Sonoran Desert," said Emily Kirkland, organizer for a nonprofit in Phoenix, Arizona.
California's power grid operators called on homeowners to save electricity and shut down air conditioning.
The persistent heat and years of drought in the American Southwest are overloading the power grids in California and Texas, exacerbating the spread of forest fires.
The National Weather Service issued warnings of excessive heat in excess of 39 degrees for five states - California, Nevada, Utah, Arizona, and parts of Colorado.
In many places, temperatures have already risen beyond this.
Phoenix now reports a new record of 48 degrees Celsius.
In other places, too, new heat records have been set several times in the past few days.
53 degrees Celsius were measured in Death Valley on Thursday.
88 percent of the southwest in a drought emergency
Experts are now warning of health risks.
The AP news agency said that high temperatures are responsible for more deaths than all other natural disasters combined.
In order to avoid heat damage, authorities are calling on the population on social media to drink plenty of water, not to be in the sun and to take regular breaks.
It is also warned not to let children or animals wait in parked cars.
Experts also fear life-threatening forest fires, which are made worse by the ongoing drought in the region.
About 88 percent of the affected regions, including the entire states of California, Oregon, Utah and Nevada, are according to surveys by the US government in a drought emergency.
Last year, the western United States was particularly hard hit by fires caused by persistent drought caused by climate change.
Dozens of people died, and in California alone an area of around 17,000 square kilometers was burned.
asc / Reuters / AP