The southwestern United States is once again struggling with the scorching heat.
The alert has been launched for around 22 million residents across California, Nevada and Arizona, where the temperature will rise above 43 degrees in the next few days.
The most extreme heat wave is expected in Death Valley: it could exceed 49 degrees.
Burning heat and humidity last month caused record temperatures in cities from Texas to Massachusetts while a record heatwave in the Northwest last summer resulted in the death of hundreds of people.
