Flash Flood Warnings in Arizona, 2019

By month

94 of 242 flash flood warnings covering Arizona in 2019 had a flash flood report inside them; 151 of 195 flash flood reports fell inside a warning, on average 89 minutes after it went out.

Arizona, 2019

Each office's whole area, 2019

An office's figures cover every county it serves, including across state lines.

Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.

• Maricopa County53
• Gila County46
• Yavapai County41
• La Paz County32
• Mohave County28
• Pima County25
• Coconino County23
• Pinal County19
• Yuma County15
• Navajo County11
• Cochise County8
• Santa Cruz County7
• Apache County3
• Graham County3

1. September 23, 201920flash flood warnings
2. September 24, 201918flash flood warnings
3. November 29, 201915flash flood warnings
4. February 15, 201911flash flood warnings
5. July 31, 201911flash flood warnings
6. August 29, 20199flash flood warnings
7. November 20, 20199flash flood warnings
8. August 3, 20198flash flood warnings
9. September 2, 20198flash flood warnings
10. July 23, 20197flash flood warnings
11. August 2, 20196flash flood warnings
12. September 7, 20196flash flood warnings

Alerts in force nowTornadoes on recordThe radar archive20182020

National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.