North Phoenix has seen its share of violent monsoon storms, with strong winds and intense downpours. As one example, a blustery storm on Aug. 3, 2017, knocked down trees and even block walls across many areas in North Phoenix.
And anyone who was in Anthem on July 31, 2012, will remember the “thousand year storm” that toppled hundreds of trees and flooded homes. That storm dumped up to 5.01 inches of rain in 90 minutes, according to the Maricopa County Flood Control District. In famously monsoon fashion, it left nearby areas as close as Sonoran Foothills completely dry.
Any flash floods from Rosa (expected Monday and Tuesday) are unlikely to match what happened in 2012. At most from Rosa, up to 3 inches of rain is expected over a 4-day period, and winds aren’t predicted to top 25 mph or so. And Rosa’s rains will be widespread, affecting much of not most of Arizona.
“We might see some isolated thunderstorms, but it’s heavy and sometimes prolonged rain that will be the concern,” said Andrew Deemer, a meteorologist at NWS office in Phoenix. “The biggest threat will be flooding from excessive rains.”
The storm’s winds are unlikely to cause the kind of damage typical the worst monsoon storms, Deemer told North Phoenix News.
That doesn’t mean any flash floods Monday and Tuesday won’t be dangerous, but the two storms are not comparable.
Officials advise anyone seeing a flooded wash to “turn around, don’t drown,” as depth can be difficult to gauge, and only a foot of water is needed to sweep a vehicle (or a person) away.