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National Weather Service Forecast Office
Tucson, Arizona
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Cyclone: Tropical Storm Norma
Date it affected AZ: September 4-6, 1970
Affected Arizona as...: Remnants (dissipated over central Baja California)

Perhaps the deadliest decaying tropical system to ever affect Arizona, Norma killed 23 people as terrifying flash floods affected large portions of central and southern Arizona. The storm itself was rather benign. However, most of her moisture was captured by a storm system dropping down the west coast of the U.S., and funneled into the state over the Labor Day weekend. Two the five inches of rain fell over much of southeast and central Arizona, with some mountains receiving 8 to 11 inches, including Mt. Lemmon with 8.74 inches, and Kitt Peak with 8.08 inches. The state rainfall record of 11.40 inches in 24 hours was set in the mountains northeast of Phoenix with this storm. Most of the people who were killed were swept away while camping in the. Avra Valley west of Tucson received considerable damage as up to 16 feet of water flowed in the normally dry wash. Flooding and extensive river bank erosion took place along the Santa Cruz River, with numerous roads and several homes flooded across metro Tucson.

Image of Tropical Storm Norma track.