Deep monsoon moisture over central Arizona allowed for strong thunderstorms with heavy rain.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS FGZ wrote it up.
Deep monsoon moisture over central Arizona allowed for strong thunderstorms with heavy rain.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Flagstaff, AZ wrote its last area forecast discussion before the first event at Jul 31, 9:29 AM MST, 4 hours 31 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 929 AM MST Sat Jul 31 2021 .SYNOPSIS...Thunderstorm coverage decreases this weekend with even less activity to begin next week. A warming trend begins early next week and peaks into mid to late week as high pressure strengthens. && .UPDATE...No significant updates were made to the forecast this morning. Less thunderstorm coverage is expected this afternoon and evening compared to the last few days with scattered chances likely. Conditions are a bit more stable with increasing heights this morning as the ridge of high pressure begins to shift towards the west. There is also some ongoing shower activity around Prescott in Yavapai County with much of the area under broken to overcast cloud cover. This factor could also limit thunderstorms for this area today. Better chances for showers and thunderstorms east of I-17 and Hwy 89 on Sunday as the ridge axis transitions over northern Arizona limiting the flow from the west-southwest. Another round of scattered activity is likely as lingering low to mid-level moisture will still be available across the region with PWATs around 1.0-1.1 inches. Things quiet down a bit as we begin the work week with high pressure strengthening towards our west. Less monsoonal flow with warming temperatures will result. && .PREV DISCUSSION /143 AM MST/...Isolated showers and thunderstorms are ongoing in central and southern Yavapai County very early this morning. Expect a very localized flood threat from any of the heavy thunderstorms for the next few hours. Another day of scattered thunderstorms will initiate around the Noon hour MST and bring periods of heavy rainfall to northern Arizona. The localized threat of flash flooding will persist as a result. Never drive through flood waters on area roads. Storm coverage will further decrease into Sunday and to start next week as high pressure begins to setup over the Southwest. Gusty winds will be possible near convection next week due to the drier air mass from northerly flow aloft and higher-based nature of storms. Suppressed convection and cloud cover will help to increase temperatures across central and northern Arizona by mid-week. Areas of heat impacts could again return to lower valleys and basins south of the Mogollon Rim and within the Grand Canyon by Wednesday. There is still moderate uncertainty in the max temperatures for Wednesday and Thursday, but temperatures anywhere from five to ten degrees warmer than this weekend are possible. && .AVIATION...For the 18Z Package...Isolated showers and thunderstorms will continue mainly southwest of KFLG and KSEZ this morning. Scattered thunderstorms re-develop area-wide after 18Z. Periods of MVFR/IFR conditions and gusty, erratic winds will occur in and around thunderstorms. Storm coverage will begin to decrease after 03Z. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered thunderstorms will continue today with flash flooding and lightning as primary hazards. Lesser storm coverage is expected for Sunday. Light winds are forecast outside of thunderstorm activity. Monday through Wednesday...Expect a drying and warming trend next week with less thunderstorm coverage each afternoon. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...LaGuardia/NL AVIATION...MCT FIRE WEATHER...NL For Northern Arizona weather information visit weather.gov/flagstaff
The Cedar City radar (KICX), 154 km away, was scanning. The volume nearest the first event began at 20:59 UTC.
2 flash flood. Local standard time, as filed.
A family of 5 was hit by a flash flood in Labyrinth Canyon that drains into Lake Powell. The wife and mother drowned.
The Verde River gauge 12 miles north-northwest of Jerome showed a 2.5 foot rise.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Flash Flood, Coconino | 2021-07-31 | 43 | Female | In Water | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2021Every state in 2021This day in weather historyWarnings in Arizona, July 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 980442, 980439.