Torrential rains drenched much of the U.S. Southwest on Monday, prompting flash-flood warnings across four states and taking the lives of two women washed away in separate incidents in Arizona. The Phoenix area was hit by a record downpour that closed sections of two major freeways, and the National Weather Service issued flash-flood warnings for parts of Arizona, California, Nevada and Utah.

Arizona Governor Jan Brewer declared a statewide emergency for the affected areas. “If you must travel, please do so with caution & BE SAFE!” Brewer said on Twitter, using the hashtag #TurnAroundDontDrown.

The downpour turned some highways into lakes. Officials said parts of both Interstates 10 and 17 were shut to traffic. A section of Interstate 15 in Nevada was closed too.

Late Monday afternoon, fire officials in suburban Mesa said as many as 100 homes were evacuated due to flooding. Two parks also were evacuated because of the possible threat caused by electric transformers that were partially submerged.