Tropical Storm Polo is expected to impact the U.S. after slamming Mexico. See its path.

Key Points:

• Former Hurricane Polo, now a tropical storm, is expected to bring heavy rain and flooding to the southwestern United States after crossing Mexico, with over 30 million people from Arizona to Iowa at risk for flash floods.
• The storm caused flooding in southern New Mexico, putting the McLeod Dam on the brink of failure and prompting flash flood emergencies and voluntary evacuations.
• Flash flood watches span more than 1,200 miles from Phoenix to Des Moines, with significant flood threats in the Four Corners Region and Central Plains; some areas in Texas may receive over 7 inches of rain.
• Polo rapidly intensified from a tropical storm to a Category 5 hurricane with peak winds of 180 mph, making it one of the strongest Pacific hurricanes on record, aided by warm waters and strong El Niño conditions.
• The storm is expected to dissipate late Tuesday night but its remnants will continue to bring rain and flooding risks through the week across parts of the Southwest and Central U.S.