An AirNow map shows air pollution in the "unhealthy" range for Portola in California, and Casa Grande in Arizona on Tuesday.

Parts of California and Arizona are at a heightened risk of flash flooding this weekend as Hurricane Priscilla shifts its path to the northeast. Newsweek reached out to the National Hurricane Center ...

California, Arizona and Nevada are urging the Trump administration to change the federal government’s approach to Colorado River water shortages. The three states say new rules should include fixing ...

Arizona, Nevada and Mexico will again live with less water from the Colorado River as drought lingers in the West, federal officials announced Friday. The Colorado River is a critical lifeline to ...