NOTE: Weather is unpredictable, so floods are too. The alerts provided err on the side of caution. It is possible that you may receive a warning and the events described do not occur. This is, in part, because floods in Pima County can develop so quickly that we have to anticipate possible events early in order to give the public reasonable time to react to the potential threat. In addition, there are many unpredictable factors that affect the extent of flooding. Flood damage may be lower or higher than what we expect. The District strives to provide the best possible information based upon the best available data and is not liable for errors. No message can guarantee your safety.
We will occasionally be wrong, but that does not mean that the safety messages should be ignored. It is your responsibility to use sound judgment in and around flood waters.
Due to the fast-changing pace of flood conditions, the flood discharge at which flood alerts are sent may vary from those indicated in the individual watercourse pages based on real-time evaluation by District staff. In addition, flood alerts may be sent to a larger inundation area than the current discharge predicts in order to provide additional warning time to residents.
Sign Up for MyAlerts
In order to receive Flood Alerts through MyAlerts requires signing up and providing a location within the inundation area of the watercourse you want alerts for. It can be a home address, work address, school address, etc. Go to the MyAlerts login page now to create an account and start receiving important safety alerts
Glossary
- ALERT - Automated Local Evaluation in Real Time. This refers to the network of rainfall, weather, and streamflow gages that are installed throughout Pima County and surrounding areas by the Flood Control District to monitor and evaluate storm and flood events. They form the basis of the alerts provided through MyAlerts.
- base flood - the base flood is what is often called the 100-year flood. It is a flood that has a 1% chance of happening in any given year. Floods of greater magnitude do occur, and floods of lesser magnitude can still cause major flooding and damage.
- cfs - cubic feet per second. This is a standard unit of measure for flow rates of floods. A cubic foot of water is 7.5 gallons, which weighs 62.5 pounds.
- 100 cfs is equal to a heavy duty crew cab pickup truck passing by every second.
- 3,500 cfs is equal to a freight train locomotive passing by every second.
- 15,000 cfs is equal to a fully loaded 747 passenger jet passing by every second.
- Inundation area - this is the area expected to be flooded by flows of a particular magnitude (cfs) based on computer modeling. Many factors affect the actual inundation area during actual flood events. The actual extents of a flood may vary from those shown on the map.