The National Weather Service (NWS) is warning that heavy rainfall could produce flash flooding across eight states, potentially impacting millions of people. The NWS posted on Facebook on Sunday afternoon to alert people in California, Utah, Colorado, Nebraska, Kansas, Oklahoma, Texas and New Mexico of the risk amid "resurgent monsoon activity."

The National Weather Service has issued flash flood warnings for Coconino County, including the Grand Canyon, on Aug. 23.

A flash flood warning was issued by the National Weather Service on Saturday at 8:28 p.m. in effect until 11:30 p.m. for Jackson County.