City of Tucson issued the following announcement on July 23.
The City of Tucson and Pima County are advising the public to use caution over the next few days when traveling through Southern Arizona because of a powerful storm system moving through the region. Forecasts from the National Weather Service show an increased chance of thunderstorms and heavy rainfall with the possibility of flash flooding through Saturday night. As washes flood, Tucson Department of Transportation and Mobility (DTM) crews are closing roadways at affected dip crossings and washes. DTM is also assisting residents concerned with flooding by offering free, self-service sandbags in the east parking lot of Hi Corbett Field, 700 S. Randolph Way, at Reid Park. This location is open 24 hours a day, seven days a week. Please bring your own shovel. You can find flood safety information from the Pima County Regional Flood Control District at the link below. The site includes information on how to sign up for flood and other emergency alerts from the Pima County Office of Emergency Management.
Original source can be found here.
Alerts Sign-up