Much of the Western United States has been experiencing a historic and unrelenting drought, the worst in the region in at least 20 years.

The most severe drought is centered in the Southwest in California, Nevada, Utah and Arizona. But areas of extreme and exceptional drought extend into the Pacific Northwest as well.

During the drought, many areas have also had to cope with extreme heat. The heat and the drought are part of a damaging feedback loop enhanced by climate change, experts say: The hotter it gets, the drier it gets. And the drier it gets, the hotter it gets.

The conditions are also fueling wildfires and exacerbating water demands.