Deep monsoon moisture and instability allowed thunderstorms to develop quickly and produce heavy rain and flash flooding.
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 and instability allowed thunderstorms to develop quickly and produce heavy rain and flash flooding.
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 Aug 10, 3:30 PM MST, 40 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 330 PM MST Wed Aug 10 2022 .SYNOPSIS...Daily showers and thunderstorms will continue across much of northern Arizona at least through the end of the week and into the weekend with deep monsoonal moisture in place. Scattered to widespread thunderstorms are likely each afternoon, with flash flooding being the main threat. && .DISCUSSION...A very active day has developed, roughly along, west and south of the Mogollon Rim. Outflows are pushing activity a bit outside of the current FFA, but it looks well placed for now. Thursday onward, with the high pressure system to our east showing no sign of major movement from model guidance, monsoonal moisture will continue across northern Arizona. As a result, expect numerous to widespread storm coverage throughout the end of the week and into the weekend. Be sure to check our social media pages (Twitter and Facebook) and local forecasts for updates on current weather conditions. && .AVIATION...For the 00Z TAF package...Widespread SHRA/TSRA along and south of KSJN-KFLG-KGCN line will continue this afternoon with ISO-SCT activity north of that line. Heavier cells are producing periods of localized reduced visibility resulting in MVFR/IFR along with strong, gusty winds. Activity will begin to weaken by 03Z. However, some storms will linger throughout the evening. Outside of TSRA, winds remain light. Expect another day of storms Thursday beginning around 19Z. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Expect widespread showers and thunderstorms each afternoon through the end of the week, bringing localized flash flooding. Seasonal temperatures and light winds outside of storms, with gusty and erratic winds near storms. Saturday through Monday...Shower and storm chances remain high through the weekend into next week. Winds will be light away from storms, with seasonal temperatures. && .FGZ WATCHES/WARNINGS/ADVISORIES... Flood Watch until 9 PM MST this evening for AZZ004-006>008-015>018- 037-038-104-106>108-115>118-137-138. && PUBLIC...Peterson/Swenson AVIATION...Peterson FIRE WEATHER...MAS For Northern Arizona weather information visit weather.gov/flagstaff
Special Weather Statement
National Weather Service Flagstaff AZ
121 PM MST Wed Aug 10 2022
AZZ007-015-102045-
Western Mogollon Rim-Coconino Plateau-
121 PM MST Wed Aug 10 2022
...A strong thunderstorm will impact portions of Coconino County
near Williams through 145 PM MST...
At 121 PM MST, Doppler radar was tracking a strong thunderstorm near
Williams, moving west at 15 mph.
HAZARD...Wind gusts up to 50 mph. Heavy rainfall.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Williams, Dogtown Lake Campground and Kaibab Lake Campground.
This includes the following highways...
Business Interstate 40 between mile markers 163 and 165.
Interstate 40 between mile markers 151 and 167.
State Route 64 between mile markers 186 and 195.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 3538 11212 3515 11211 3518 11241 3546 11235
TIME...MOT...LOC 2021Z 101DEG 12KT 3528 11223
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH
HumphreysSpecial Weather Statement
National Weather Service Flagstaff AZ
138 PM MST Wed Aug 10 2022
AZZ008-037-038-102115-
Yavapai County Valleys and Basins-Yavapai County Mountains-Oak Creek
and Sycamore Canyons-
138 PM MST Wed Aug 10 2022
...A strong thunderstorm will impact portions of Coconino and Yavapai
Counties near the Village of Oak Creek through 215 PM MST...
At 137 PM MST, Doppler radar was tracking a strong thunderstorm over
Village At Oak Creek, or near Sedona. This storm was nearly
stationary.
HAZARD...Wind gusts up to 50 mph, nickel size hail, and heavy
rainfall.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Sedona and Village At Oak Creek.
This includes the following highways...
State Route 179 between mile markers 302 and 311.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 3475 11168 3470 11174 3476 11189 3485 11177
TIME...MOT...LOC 2037Z 136DEG 3KT 3477 11176
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH
HumphreysPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
248 PM MST WED AUG 10 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0230 PM FLASH FLOOD 2 NNW PONDEROSA PARK 34.50N 112.51W
08/09/2022 YAVAPAI AZ PUBLIC
GCRA3 HYDRO GAUGE AT GRANITE CREEK
REGISTERED A NEARLY 4 FOOT RISE IN 1 HOUR
FROM 7.19 FEET AT 2130Z, CRESTING AT 10.96
FEET AT 2230Z. CURRENT GUIDANCE SHOWS 10
FEET BEING MODERATE FLOOD STAGE AND 11 FEET
BEING MAJOR FLOOD STAGE. THE GAUGE DROPPED
BACK BELOW MODERATE FLOOD STAGE AT 2345Z AND
BELOW MINOR FLOOD STAGE AT 0045Z.
&&
JJMSpecial Weather Statement
National Weather Service Flagstaff AZ
320 PM MST Wed Aug 10 2022
AZZ008-037-102245-
Yavapai County Valleys and Basins-Yavapai County Mountains-
320 PM MST Wed Aug 10 2022
...A strong thunderstorm will impact portions of Yavapai County
through 345 PM MST...
At 320 PM MST, Doppler radar was tracking a strong thunderstorm over
Cordes, or 21 miles southeast of Prescott Valley, moving west at 5
mph.
HAZARD...Wind gusts up to 50 mph and penny size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Cordes Junction, Cordes Lakes, Mayer, Cordes, Spring Valley, Bumble
Bee, Turney Gulch Group Campground and Hazlett Hollow Campground.
This includes the following highways...
Interstate 17 between mile markers 255 and 268.
State Route 69 between mile markers 263 and 272.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 3442 11209 3425 11204 3415 11229 3441 11237
TIME...MOT...LOC 2220Z 076DEG 6KT 3432 11215
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH
ETThe Flagstaff radar (KFSX), 91 km away, was scanning. The volume nearest the first event began at 23:07 UTC.
3 flash flood. Local standard time, as filed.
Heavy rain over the northern portion of the Pipeline fire cause flash flooding over Highway 89. Both directions were closed due to the flooding between milepost 428 and 430.
Two feet of water was flowing in Yaber Wash. The water was 40 to 50 feet wide with low water crossings flooded.
A video of a flood in Big Bug Creek was posted on social media. The creek is normally dry.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2022Every state in 2022This day in weather historyWarnings in Arizona, August 2022
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: 1052186, 1052188, 1052187.