Flash flooding poses a significant risk to urban areas, highways, and small streams in the Tucson area, including locations such as Sahuarita, Green Valley, and Mount Lemmon. Flood-prone areas like Harrison Rd at Pantano Wash and Tanque Verde Loop Rd are particularly vulnerable. The saturated ground increases the likelihood of swift water runoff, which can be dangerous for drivers and pedestrians. Residents in low-lying areas should be prepared for potential evacuations and property damage.