Deep monsoon moisture remained over northern Arizona with several flash floods form the 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 remained over northern Arizona with several flash floods form the 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 22, 1:29 PM MST, 2 hours 1 minute earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 129 PM MST Thu Jul 22 2021 .SYNOPSIS...Scattered showers and isolated thunderstorms today begin to expand in coverage from east to west overnight. The threat of flash flooding will increase into the weekend as thunderstorms occur across much of northern Arizona. && .DISCUSSION...There is a significant threat of flash flooding from today through Saturday, and possibly Sunday. Severe thunderstorms are also possible from Friday afternoon into the overnight hours. High pressure remains entrenched over the Four Corners today and is bringing clockwise flow aloft across northern Arizona. Thunderstorms that formed over the high terrain are slowly beginning to move into the lower elevations on light steering flow. Localized heavy rainfall has been observed with these isolated to scattered thunderstorms. Expect expanding coverage of showers and storms throughout the remainder of the afternoon and evening hours today. A weak disturbance is rotating around the high pressure this afternoon in the central Rocky Mountains and is progged to enter the Four Corners area later this evening. Accompanying this will be enhanced dynamics to support overnight convection, beginning first in Apache County this evening and spreading southwestward overnight. High resolution guidance is showing high chances for widespread rainfall tonight in mainly northeastern and east- central Arizona, with areas of embedded heavy rainfall. The current Flash Flood Watch remains in effect until late Saturday evening for a prolonged threat of flash flooding. There is moderate confidence in a slight downturn in activity by mid to late Friday morning, but another round of afternoon/evening thunderstorms on Friday are likely. A second dynamic system, this time an inverted trough moving westward from the southern southern Rockies, will then provide enough support for another round of overnight heavy rainfall Friday night. The inverted trough is also progged to create enough wind shear to support prolonged updraft development over northern Arizona on Friday. The result would be a combination of heavy rainfall leading to flash flooding, but also some severe thunderstorms. The severe thunderstorm threat should be monitored even into Friday night on the leading edge of another large storm complex moving into the state from the east. Significant flash flooding is again possible into Saturday as an already saturated ground is favored to produce enhanced runoff. The synoptic setup on Sunday is following a trend that began yesterday where the inverted trough stalls out over southern Arizona and continues to produce heavy rainfall on Sunday. The current Flash Flood Watch will have to be monitored against growing confidence in these conditions for later this weekend. Scattered thunderstorm coverage remains in the forecast early next week, but a bit less than what is expected over the next few days, as moisture remains over northern Arizona. && .AVIATION...For the 00Z package...Scattered showers and thunderstorms will bring isolated IFR visibilities in heavy rain through this evening. Coverage of showers and storms only further increases from east to west after 00Z, with areas of MVFR/IFR conditions likely tonight in northeastern and east-central Arizona. Gusty outflow winds near any storm activity with otherwise light winds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...There is a significant flash flood potential through Saturday night. Scattered to numerous showers and thunderstorms are expected through Saturday with storms continuing each night. Widespread wetting rains are likely with embedded areas of heavy rain. Storm coverage will begin to decrease by early next week. && .FGZ WATCHES/WARNINGS/ADVISORIES...Flash Flood Watch through Saturday evening FOR AZZ006>008- 011>018-037-038-040. && PUBLIC...NL AVIATION...NL FIRE WEATHER...NL For Northern Arizona weather information visit weather.gov/flagstaff
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1047 AM MST THU JUL 22 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0500 PM FLASH FLOOD 20 NW VALLE 35.82N 112.42W
07/18/2021 COCONINO AZ OFFICIAL NWS OBS
CATARACT CREEK AT REDLANDS CROSSING ROSE 2
FEET IN LESS THAN AN HOUR DUE TO HEAVY
RAINFALL UPSTREAM.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1058 AM MST THU JUL 22 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0500 PM FLASH FLOOD SUPAI 36.22N 112.69W
07/21/2021 COCONINO AZ OFFICIAL NWS OBS
HAVASU CREEK AT SUPAI RIVER GAUGE SHOWED A
RISE OF 18 INCHES IN ABOUT AN HOUR. IT TOOK
ABOUT 6 HOURS FOR THE RIVER TO RETURN TO ITS
ORIGINAL LEVEL.
&&
MDPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1209 PM MST THU JUL 22 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0400 PM FLASH FLOOD 1 NNE GRAND CANYON VILL 36.07N 112.13W
07/21/2021 COCONINO AZ PARK/FOREST SRVC
BRIGHT ANGEL TRAIL WAS WASHED OUT FROM
FLOODING.
&&
MDThe Cedar City radar (KICX), 139 km away, was scanning. The volume nearest the first event began at 22:31 UTC.
2 flash flood. Local standard time, as filed.
Flash flooding was reported in main side canyons that flow into Marble Canyon and the Colorado River just west of Navajo Bridge. The two named side canyons were Soap Creek and Jackass.
Heavy rain from a thunderstorm caused flooding on State Route 260 on the south side of Show Low. A car got stuck in the high water. Flooding was also reported east of Show Low near Highway 60 and Little Mormon Lake Road meet and on to the Second Knoll Shooting Range (Forest Road 206).
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: 979006, 978778.