Maricopa County warns of stronger monsoon, urges residents not to drive through flooded roadways

A Maricopa County staff member warned that the county is anticipating a wetter-than-usual monsoon beginning in early July and continuing through the summer, increasing the risk of both heavy thunderstorms and heat-related health hazards.

The warning matters because heavier monsoon circulation can draw moisture from across the United States into the region, raising dew points and making heat more dangerous while also producing intense rainfall that can flood washes and low water crossings, the staff member said.

"We're actually anticipating a wetter monsoon than we've had in the past," the Maricopa County staff member said, adding that a dry winter and spring set the stage for a stronger monsoon circulation. The staff member said a stronger circulation "is able to tap into the moisture sources around The United States and brings it into our area to feel those thunderstorms." The staff member also warned that "a strong monsoon circulation also can bring strong heat potential."

Officials emphasized two public-safety hazards: rapid flooding in desert washes and reduced evaporative cooling from higher humidity. The staff member said heavy rains can produce "1, 2, 3 inches an hour," which is sufficient to cause water to run in washes and create flooded roadways. "If you encounter a roadway that is flooded, don't cross it," the staff member said. "It takes 6 inches to knock you off your feet just standing in the water. Let alone if it's a foot or above, that actually can float your vehicle away. It's not worth the risk."

Maricopa County operations will be staffed around the clock for the season, the staff member said, to monitor storm impacts and respond to flooding and health hazards. Residents were urged to avoid low water crossings, monitor local alerts, and take heat-safety precautions when humidity is high.

County officials did not provide specific thresholds for issuing closures of roads or bridges in the briefing. They also did not specify which neighborhoods or exact dates beyond the early-July period would be most affected.