Flash flood warnings covered parts of four states Monday, from Arizona’s Sonoran Desert to the Great Lakes region, as the National Weather Service tracked five active alerts tied to thunderstorms capable of dropping several inches of rain in a matter of hours.
In eastern Kansas, the National Weather Service office in Pleasant Hill, Missouri, warned that a storm over southern Johnson County, Kansas, had already produced between 1.5 and 2 inches of rain by 4:56 a.m. CDT Monday, with rainfall rates of 1 to 2 inches per hour continuing. That warning was set to expire at 11 a.m. CDT.
Farther west, the National Weather Service placed Southeast Arizona under a flash flood warning beginning at 2 p.m. MST, covering the Tucson metro area along with Green Valley, Marana and Vail, plus South Central and Southeast Pinal County, the Baboquivari and Santa Catalina/Rincon mountain ranges, the Tohono O’odham Nation, and the Upper Santa Cruz River and Altar Valleys. Forecasters said excessive rainfall continued to raise the risk of flash flooding across the region, a pattern typical of the summer monsoon season that regularly sends sudden runoff through desert washes and low-lying roads.
The most geographically sprawling warning stretched across the Midwest, spanning northern Indiana, southern Michigan and northern Illinois. It listed more than two dozen counties, including Elkhart, Lagrange, Steuben, Noble, De Kalb, Allen, Whitley, Huntington, Wabash, Miami, Cass, Fulton, Marshall, Pulaski, Starke, and both the northern and southern portions of St. Joseph, Kosciusko and La Porte counties in Indiana; Branch, Van Buren, Kalamazoo, Calhoun and both northern and southern Berrien counties in Michigan; and Grundy and La Salle counties in Illinois, along with Livingston County.
The National Weather Service said flash flooding from excessive rainfall remained possible across that corridor and urged residents to monitor forecasts and be prepared to act if additional warnings are issued.
Across all five warnings, forecasters repeated the same core message: most flood deaths happen in vehicles, and drivers who encounter flooded roads should turn around rather than attempt to cross. With storms producing rain rates of 1 to 2 inches per hour in some areas, the Weather Service cautioned that continued downpours could push already-saturated ground, streams and low-water crossings past their capacity as the day goes on.