Flash Flooding and Damaging Winds in Arizona, July 22 to 23, 2021

Name: Flash Flooding and Damaging Winds in Arizona, July 22 to 23, 2021
Start: 2021-07-22T16:00
End: 2021-07-23T18:30
Location: Arizona

July 22 to 23, 2021 · NWS PSR · 26 events in 3 counties and zones

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $1.5 million
Crop damage: None recorded
Events: 26

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.

What happened

The episode as NWS PSR wrote it up.

Strong to severe thunderstorms developed in an unstable atmosphere in the afternoon of the 22nd. Storms initially developed over the high terrain of northern and eastern Arizona as well as near the Table Top mesa area south of Phoenix. High DCAPE promoted strong thunderstorm downbursts. The downbursts generated outflows that progressed into the greater Phoenix metro area and led to the development of additional scattered thunderstorm. The thunderstorms in the metro area produced damaging winds that led to numerous downed trees, downed power poles, and other property damage. The storms were also nearly stationary, under weak steering flow, and produced very heavy rainfall with rain rates around 1.5-2.0 inches per hour and briefly higher in the strongest storms. This led to considerable flash flooding around Phoenix with several road closure and significant flow in major washes. Even after the strongest storms in Phoenix subsided in the late evening of the 22nd, areas of moderate to heavy rain continued from northeast to southwest through the night and through mid-afternoon on the 23rd. The continued rain through the 23rd was aided by a strengthening diffluent flow regime between the monsoon high to the north and a retrograding upper low moving west through New Mexico. Additional significant flash flooding was observed on the 23rd, mostly in the foothills north of the Phoenix metro, with many road closures, flowing washes and creeks, and some water rescues.

What forecasters said that day

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 Phoenix, AZ wrote its last area forecast discussion before the first event at Jul 22, 1:58 PM MST, 2 hours 2 minutes earlier.

Area forecast discussion, Jul 22, 1:58 PM MST, 2 hours 2 minutes before

Area Forecast Discussion
National Weather Service Phoenix AZ
158 PM MST Thu Jul 22 2021

.SYNOPSIS...
A low pressure system will drift slowly towards the Desert Southwest
over the next few days. With abundant Monsoon moisture in place,
thunderstorms will be likely, particularly across portions of
Arizona. The strongest storms will be capable of producing heavy
rainfall and areas of flash flooding. Temperatures will also be well
below normal beginning Friday. Warmer and drier conditions are
anticipated next week as the low pressure system lifts northward
into the Great Basin.

&&

.DISCUSSION...
Water vapor imagery clearly shows a well-defined westward moving
upper low over the Rio Grande Valley of Texas this afternoon.
The leading edge of the influence of this feature is moving across
New Mexico, approaching a mid-level anticyclone positioned over
northern Arizona. Some modest drying was indicated in morning
Phoenix soundings (including a special 16Z sounding), especially
aloft, but overall there's plenty of moisture available to support
thunderstorm development this afternoon. SPC mesoanalysis showed a
rich axis of moisture (PW values near 2 inches) oriented across
the lower Colorado River Valley, with similar values spreading
into southeast California. More ample heating today is supporting
a very unstable air mass across all desert locations, with MLCAPE
values of 1500-2000+ J/kg in place. Thunderstorm activity should
remain fairly isolated through this afternoon, but any
thunderstorm that develops has the potential to quickly intensify,
with heavy rainfall, gusty winds, and small hail a threat.
Blowing dust will also be possible across southwest Arizona and
southeast California in vicinity of any thunderstorms.

Almost all CAM guidance continues to suggest thunderstorm
potential will increase markedly this evening into tomorrow. The
first wave of activity will likely develop across western New
Mexico into the White Mountains of eastern Arizona. Although
specific details are different amongst various model signals,
there's still a very strong signal overall that multiple episodes
of heavy rain will develop across southern Gila County and move
into the lower deserts overnight tonight, and again redeveloping
Friday afternoon. This setup has the potential for significant
rainfall over the higher terrain and lower deserts of south-
central Arizona. Daily rainfall records will be in jeopardy on
Friday (including 0.41 inches at Phoenix). The WPC Excessive
Rainfall Outlook has been upgraded to Moderate for Friday for
southern Gila County, with significant flash flooding potential
expected.

Scattered showers and thunderstorms are likely to continue during
the day Saturday into early Sunday. Overall rainfall totals are
expected to range between 2-4" across the higher terrain east of
Phoenix, to 1-2" across the deserts of Maricopa and northwest
Pinal Counties. Locally higher totals are likely. Rainfall
amounts of these magnitudes have the potential to produce very
dangerous flash flooding, particularly in normally dry washes and
even along mainstem rivers such as the Agua Fria, Hassayampa and
Tonto Creek. Model consensus indicates rain totals drop off
considerably west of Maricopa County.

The one silver lining to all of the clouds and rain is temperatures
will be well below normal through at least Monday, which will reduce
the Heat Risk. High temperatures in Phoenix will likely remain below
the 100 degree mark for 4 consecutive days, Friday through Monday.
The last time this happened during July or August was in August of
2014, when 6 consecutive days below 100 degrees were recorded.

Ensembles are in good agreement warmer and drier conditions will
return to the Desert Southwest by Tuesday as the low pressure system
gets pulled rapidly northward into the Great Basin.

&&

.AVIATION...Updated at 1910Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds have become mostly light and variable across the metro with
winds starting to favor more of a south to southwest component.
Expect winds to continue to favor more of a westerly component
going through the early afternoon hours with some gusts upwards of
15-20 kts possible at times later this afternoon. Chances for
showers and thunderstorms will increase (20-40%) going into the
late evening and overnight hours across the Phoenix area, though
the exact timing and evolution of this convection remains
uncertain. Any thunderstorms that do develop will be capable of
producing gusty erratic outflow winds with HREF guidance showing a
30-50% chance of outflow winds exceeding 30 kts. Chances for more
widespread precipitation increase (50-60%) going through tomorrow
morning and into the afternoon across the Phoenix area. Cigs are
expected to fall to around 7-8 kft tonight with cigs falling to
around 6 kft or perhaps slightly lower with any showers and
thunderstorms that pass through.

Southeast California/Southwest Arizona including KIPL and KBLH:
Winds will generally favor a south to southeast component at the
terminals through the period. Speeds are expected to remain elevated
around 8-12 kts with some gusts to around 20 kts this
afternoon/evening, especially from any outflow winds from Baja.
Chances for showers and thunderstorms remain low for this afternoon
(~20%) but can't rule out some development near the terminals.
However, overall confidence remains too low to mention in the TAFs
at this time. Cloud bases are expected to mostly remain aoa 10 kft
through the TAF period.

&&

.FIRE WEATHER...
Sunday through Thursday:

After a very wet period, isolated to scattered thunderstorms
will continue Sunday into next week with the potential for
locally heavy rainfall. Storm activity is anticipated to spread
as far west as southeast California, especially on Sunday and
Monday with most storms having good potential for wetting rain
(0.10" or more). Tuesday will see gradual drying conditions, but
enough moisture will linger for continued daily thunderstorm
chances on Wednesday and Thursday, especially across the higher
terrain. Apart from thunderstorms, winds will favor familiar
diurnal patterns.

Min RH levels are expected to be in the 30-45% range across south-
central Arizona (45-60% higher terrain of south-central AZ) and 25-
35% across southeast California and southwest Arizona through
Monday. Max RH levels, outside of storms, will be 55-70% most places
(60-90% higher terrain of south-central AZ). Values will fall into
a more typical range for the summer by Tuesday, with min RH
readings ranging from 15-20 percent in southeast California to
20-35% in south-central Arizona.

&&

.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flash Flood Watch from 5 PM MST this afternoon through Saturday
     evening for AZZ534-537>546-548>551-553>555-559.

     Flash Flood Watch through Saturday evening for AZZ547-552-
     556>558-560>563.

CA...None.
&&

DISCUSSION...Rogers/Hirsch
AVIATION...Smith
FIRE WEATHER...Rogers/Kuhlman

In the hours before

Local storm report, Jul 22, 12:12 PM MST, 3 hours 48 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
1212 PM MST THU JUL 22 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1030 PM     HAIL             2 SW PARADISE VALLEY    33.51N 111.97W
07/21/2021  E0.50 INCH       MARICOPA           AZ   PUBLIC

            *** DELAYED REPORT *** SOCIAL MEDIA POST
            SHOWS ACCUMULATING HAIL ALONG NORTH 53RD ST.
            BETWEEN EAST PALOMINO RD. AND EAST
            WONDERVIEW RD. WITH SIZES ESTIMATED TO BE
            SIMILAR TO NEARBY REPORTS.

1030 PM     HAIL             2 WSW SCOTTSDALE        33.49N 111.96W
07/21/2021  E0.50 INCH       MARICOPA           AZ   PUBLIC

            *** DELAYED REPORT *** RESPONSE TO SOCIAL
            MEDIA POST REPORTED HAIL AT NORTH 56TH ST.
            AND EAST OSBORN RD.

1030 PM     HAIL             3 W SCOTTSDALE          33.49N 111.97W
07/21/2021  E0.50 INCH       MARICOPA           AZ   PUBLIC

            *** DELAYED REPORT *** SOCIAL MEDIA POST
            SHOWS HANDFUL OF HAIL WITH SIZE ESTIMATED
            FROM VIDEO NEAR EAST INDIAN SCHOOL RD. AND
            NORTH 50TH ST.

&&

Local storm report, Jul 22, 12:13 PM MST, 3 hours 47 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
1213 PM MST THU JUL 22 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0357 PM     HAIL             AVONDALE                33.44N 112.36W
07/21/2021  E0.25 INCH       MARICOPA           AZ   PUBLIC

            *** DELAYED REPORT *** PEA-SIZED HAIL WITH
            WIND GUSTS ESTIMATED TO 35-40 MPH.

&&

GL

Special weather statement, Jul 22, 3:06 PM MST, 54 minutes before

Special Weather Statement
National Weather Service Phoenix AZ
306 PM PDT Thu Jul 22 2021

CAZ562-566-567-222300-
Imperial County West CA-Imperial County Southwest CA-
Imperial Valley CA-
306 PM PDT Thu Jul 22 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN IMPERIAL COUNTY
UNTIL 400 PM PDT...

At 305 PM PDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Mt. Signal, or 10 miles south of Plaster City, moving
north at 10 mph.

Winds in excess of 40 mph along with blowing dust and reduced
visibilities down to two miles will be possible with this storm.

Locations impacted include...
Plaster City, Ocotillo, Mt. Signal, Dixieland and Coyote Wells.

This includes the following highways...
CA Interstate 8 near mile marker 1, and between mile markers 3 and
30.
CA Route 98 between mile markers 1 and 26.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3280 11610 3286 11593 3276 11564 3266 11559
      3262 11610 3279 11611
TIME...MOT...LOC 2205Z 161DEG 8KT 3264 11579

Iniguez

Special weather statement, Jul 22, 3:43 PM MST, 17 minutes before

Special Weather Statement
National Weather Service Phoenix AZ
343 PM MST Thu Jul 22 2021

AZZ538-539-559-222330-
Sonoran Desert Natl Monument AZ-Tonopah Desert AZ-Gila Bend AZ-
343 PM MST Thu Jul 22 2021

...SIGNIFICANT WEATHER ADVISORY FOR MARICOPA COUNTY UNTIL 430 PM
MST...

At 342 PM MST, Doppler radar was tracking a strong thunderstorm over
Gila Bend, moving north at 20 mph.

Wind gusts up to 50 mph will be possible with this storm.

Locations impacted include...
Gila Bend, Gila Bend Auxiliary Field, Bosque and Cotton Center.

This includes the following highways...
AZ Interstate 8 between mile markers 109 and 131.
AZ Route 238 between mile markers 1 and 10.
AZ Route 85 between mile markers 1 and 11, and between mile markers
119 and 137.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3279 11242 3271 11276 3310 11292 3319 11261
TIME...MOT...LOC 2242Z 162DEG 19KT 3291 11268

Iniguez

Special weather statement, Jul 22, 4:00 PM MST, 0 minutes before

Special Weather Statement
National Weather Service Phoenix AZ
400 PM PDT Thu Jul 22 2021

CAZ562-566-567-230000-
Imperial County West CA-Imperial County Southwest CA-
Imperial Valley CA-
400 PM PDT Thu Jul 22 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN IMPERIAL COUNTY
UNTIL 500 PM PDT...

At 400 PM PDT, Doppler radar was tracking a strong thunderstorm over
Ocotillo, moving northwest at 20 mph.

Wind gusts up to 50 mph along with blowing dust and reduced
visibilities down to two miles will be possible with this storm.

Locations impacted include...
Plaster City, Ocotillo, Mt. Signal, Mountain Spring, El Centro Naval
Airfield, Coyote Wells, Dixieland and Seeley.

This includes the following highways...
CA Interstate 8 near mile marker 1, and between mile markers 3 and
35.
CA Route 98 between mile markers 1 and 29.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3280 11610 3304 11610 3308 11590 3286 11563
      3267 11554 3262 11609 3268 11611
TIME...MOT...LOC 2300Z 154DEG 19KT 3276 11596

Iniguez

The radar

The Phoenix radar (KIWA), 102 km away, was scanning. The volume nearest the first event began at 23:00 UTC.

Open the radar archive at this moment

Event by event

19 flash flood, 6 thunderstorm wind, 1 lightning. Local standard time, as filed.

Thunderstorm Wind, Maricopa

When: July 22, 4:00 PM MST
Where: Maricopa County, 2.41 mi ESE of Gila Bend
Measured: 52 kt (60 mph) estimated gust
Property damage: $10,000
Reported by: COOP Observer
Coordinates: 32.939, -112.680

Multiple RVs were damaged or displaced after strong to severe winds impacted the Sonoran Desert RV Park. 10 RVs were moved 5 to 6 feet and one was knocked over on its side. Additionally, one RV had windows broken and another had a cracked glass door. Winds estimated based on damage and timing based on radar. No injuries were reported.

Thunderstorm Wind, Maricopa

When: July 22, 8:05 PM MST
Where: Maricopa County, 3.4 mi WNW of Phoenix Deer Vly Arp
Measured: 48 kt (55 mph) estimated gust
Property damage: $3,000
Reported by: Public
Coordinates: 33.698, -112.135

Social media photos and videos show several downed palo verde trees of varying sizes along Pinnacle Peak Road near 35th Avenue. Some of the palo verdes fell into the road. Timing estimated from radar. No injuries reported.

Thunderstorm Wind, Maricopa

When: July 22, 8:15 PM MST
Where: Maricopa County, 2.44 mi W of Phoenix Deer Vly Arp
Measured: 48 kt (55 mph) estimated gust
Property damage: $5,000
Reported by: Public
Coordinates: 33.683, -112.122

Photo of a large shallow-rooted tree that fell between two homes near 29th Avenue and Deer Valley Road and caused minor damage to both. Timing estimated from radar. No injuries reported.

Flash Flood, Pinal

When: July 22, 8:35 PM MST to 8:50 PM MST
Where: Pinal County, 3.57 mi NE of Arizona City to 3.42 mi NW of Toltec
Cause: Heavy Rain
Reported by: Public
Coordinates: 32.810, -111.670

Flash flooding reported near a truck stop at Sunland Gin Road and Interstate-10. Water was a few feet deep in spots. Timing estimated from radar rainfall estimates. No damages or injuries reported.

Flash Flood, Pinal

When: July 22, 8:35 PM MST to 8:50 PM MST
Where: Pinal County, 2.89 mi E of Arizona City to 2.98 mi E of Arizona City
Cause: Heavy Rain
Reported by: Public
Coordinates: 32.783, -111.670

Social media video showed water flowing over Sunland Gin Road near Tonto Road. Time estimated from radar rainfall estimates. No damages or injuries reported.

Thunderstorm Wind, Maricopa

When: July 22, 9:10 PM MST
Where: Maricopa County, 1.33 mi E of Papago Aaf Arpt
Measured: 52 kt (60 mph) estimated gust
Property damage: $10,000
Reported by: Broadcast Media
Coordinates: 33.480, -111.927

A microburst caused significant damage in south Scottsdale with numerous downed trees of various sizes and with some falling on parked vehicles. At Scottsdale Road and Thomas Road one tree fell on top of two cars, damaging the frame and busting the window of one. Nearby at Thomas and 70th Street a carport at an apartment complex was destroyed with a portion of it collapsing on a parked SUV. Winds estimated around 60 mph based on damage reports in the affected area. Timing estimated from radar. No injuries were reported.

Thunderstorm Wind, Maricopa

When: July 22, 9:20 PM MST
Where: Maricopa County, 1.53 mi ENE of Papago Aaf Arpt to 2.17 mi NE of Papago Aaf Arpt
Measured: 56 kt (64 mph) estimated gust
Property damage: $300,000
Reported by: Broadcast Media
Coordinates: 33.490, -111.926

A microburst caused significant damage in Downtown Scottsdale with numerous toppled or snapped trees. Amongst the received reports, half a dozen trees were reportedly uprooted around Fashion Square outlet mall. At least a couple trees fell on vehicles. Two palm trees in front of the Galleria Corporate Center were snapped in half. A carport at the San Marin apartment complex was blown over and caused damage to the several cars parked underneath. A media report showed a restaraunt had a partial roof torn off while customers were inside. In all there were like many more unreported damages with unkown costs. Winds were estimated around 60-65 mph in the downtown area based on damage. Timing estimated from radar. No injuries were reported.

Thunderstorm Wind, Maricopa

When: July 22, 9:25 PM MST
Where: Maricopa County, 3.34 mi NNE of Papago Aaf Arpt to 3.93 mi ESE of Paradise Vly
Measured: 70 kt (81 mph) estimated gust
Property damage: $1.0 million
Reported by: Broadcast Media
Coordinates: 33.524, -111.927

A microburst caused considerable damage from the McCormick Rach area and down to Scottsdale Road and McDonald Road with hundreds of downed trees and several downed power poles that caused a power outage to the area. The McCormick Ranch golf course had at least 220 large trees uprooted or snapped across the property. Several trees also fell on homes around the course. Course officials estimated the damage costs to the course at $600,000. At a shopping plaza on the southwest side of the course a palm tree fell onto a business, causing damage to the roof. Across Indian Bend Road to the south, McCormick-Stillman Railroad Park received extensive damage with several large trees, including pines, being uprooted or snapped across the park. Some of the toppled trees fell on park buildings and trains. At least 6 power poles were downed or snapped due to the winds with most of the poles along Scottsdale Road between Lincoln Drive and McDonald Drive. In this area 5 large trees were also uprooted with a couple of them being pine trees. Winds were estimated around 70-80 mph based on damage. Timing estimated from radar. There were no injuries.

Lightning, Maricopa

When: July 22, 9:30 PM MST
Where: Maricopa County, 0.55 mi NW of Cactus
Property damage: $10,000
Reported by: Broadcast Media
Coordinates: 33.586, -112.056

Lightning struck a house and sparked a fire in in the attic. No one was home at the time of the strike. Fire crews were able to keep the damage at a minimum. Time estimated from radar. No injuries reported.

Flash Flood, Maricopa

When: July 22, 9:50 PM MST to July 23, 2:40 AM MST
Where: Maricopa County, 2.05 mi N of Scottsdale to 1.09 mi NNW of Scottsdale
Cause: Heavy Rain
Property damage: $15,000
Reported by: Broadcast Media
Coordinates: 33.509, -111.906

Very heavy rain fell in the Scottsdale area beginning around 2100MST on the 22nd. A rain gage at Indian School Road and Indian Bend Wash measured a little over 2 inches in 50 minutes. A significant amount of runoff collected in Indian Bend Wash that flooded multiple low water road crossings as well as flooded recreational parks built in the wash. Osborn Road across the wash was impassable with roughly 2 feet of moving water over the road. One vehicle became stuck trying to cross the flood waters and had to be rescued by the fire department. A flood control streamflow gage on Indian School Road, a block north, exceeded alarm stage at 2146MST on the 22nd and did not fully recede below alarm stage until 0239MST on the 23rd. Helicopter footage after sunrise on the 23rd still showed minor levels of flooding in the wash. No injuries were reported.

Flash Flood, Maricopa

When: July 22, 10:14 PM MST to July 23, 12:00 AM MST
Where: Maricopa County, 2.44 mi WSW of Phoenix Turf Arpt to 2.41 mi WSW of Phoenix Turf Arpt
Cause: Heavy Rain
Property damage: $4,000
Reported by: Department of Highways
Coordinates: 33.610, -112.115

The Thunderbird Road underpass at Interstate-17 became impassable with 2 to 3 feet of standing water after over 1 inch of rain fell in roughly one hour. One vehicle stalled in the flood water and had to be towed out. The road was eventually closed. No injuries reported.

Flash Flood, Maricopa

When: July 22, 10:21 PM MST to July 23, 12:00 AM MST
Where: Maricopa County, 2.18 mi W of Phoenix Turf Arpt to 2.09 mi W of Phoenix Turf Arpt
Cause: Heavy Rain
Property damage: $5,000
Reported by: Department of Highways
Coordinates: 33.625, -112.117

Arizona Department of Transportation reported the Greenway Road underpass at Interstate-17 was flooded and the on/exit ramps were also under water. A couple vehicles became stranded in the flood water. This forced the closure of the underpass. No damages or injuries were reported.

Flash Flood, Gila

When: July 23, 12:15 AM MST to 12:35 AM MST
Where: Gila County, 3.24 mi NW of Government Hill to 5.48 mi NW of Government Hill
Cause: Heavy Rain / Burn Area
Reported by: Department of Highways
Coordinates: 33.700, -111.194

Arizona Department of Transportation closed Highway-188 between mile posts 246 and 253 due to flooding with an overtopped drainage cut and debris on the road. Runoff may have been enhanced by the 2020 Bush burn scar. Timing estimated from radar. No damages or injuries were reported.

Flash Flood, Gila

When: July 23, 2:00 AM MST to 2:30 AM MST
Where: Gila County, 1.32 mi SW of Miami to 1.09 mi SW of Miami
Cause: Heavy Rain / Burn Area
Property damage: $10,000
Reported by: Emergency Manager
Coordinates: 33.386, -110.886

A local bridge along Mackey Camp Road reportedly washed out following a rapid rise in flood waters in Bloody Tanks Wash. Runoff may have been enhanced by the 2021 Telegraph burn scar. Timing based on upstream rain gage and radar. No injuries reported.

Flash Flood, Maricopa

When: July 23, 10:00 AM MST to 10:20 AM MST
Where: Maricopa County, 0.76 mi SW of Cactus to 0.74 mi SW of Cactus
Cause: Heavy Rain
Reported by: Department of Highways
Coordinates: 33.571, -112.058

Hatcher Road was closed due to flooding between 11th Street and 11th Place. Nearby rain gages measured from 0.25 to 1.10 inches. Time estimated from radar and rain gages. No damages or injuries reported.

Flash Flood, Maricopa

When: July 23, 11:10 AM MST to 12:40 PM MST
Where: Maricopa County, 0.69 mi SW of Fountain Hills to 0.67 mi SW of Fountain Hills
Cause: Heavy Rain
Reported by: Trained Spotter
Coordinates: 33.614, -111.729

Heavy rain fell in Fountain Hills with a few rain gages measuring a little over 1 inch in an hour. Rapid runoff led to significant flow in Ashbrook Wash. Social media videos showed at least 6-12 inches of swift moving water over Fountain Hills Boulevard near Ashbrook Drive as well as over Del Cambre Avenue near Grande Boulevard. The roads were impassable to all traffic. No damages or injuries were reported.

Flash Flood, Maricopa

When: July 23, 11:45 AM MST to 2:00 PM MST
Where: Maricopa County, 8.55 mi N of Ft McDowell to 7.76 mi N of Ft McDowell
Cause: Heavy Rain
Reported by: Department of Highways
Coordinates: 33.754, -111.678

A little over 1 inch of rain fell in roughly 1 hour east of Cave Creek between 1000MST and 1100MST. Light to moderate rain was falling beforehand and continue to fall through the early afternoon. Maricopa County Department of Transportation reported at 1335MST that Needlerock Road north of Rio Verde Drive was closed due to flooding. No injuries or damage was reported.

Flash Flood, Maricopa

When: July 23, 12:38 PM MST to 4:31 PM MST
Where: Maricopa County, 3.51 mi ENE of New River to 3.42 mi ENE of New River
Cause: Heavy Rain
Property damage: $100,000
Reported by: Fire Department/Rescue
Coordinates: 33.930, -112.070

Two people had to be rescued from their mobile home near Central Avenue and Mingus Road after flood waters rapidly overcame the area. Water was reportedly flowing through their windows and there was concern that the home would flow away. They were rescued via helicopter because responders were unable to reach the home on the ground with multiple impassable flooded roads. Rain gages in the area measured over 1.5 inches of rain in less than an hour The two people were uninjured, but their two dogs did not survive.

Flash Flood, Maricopa

When: July 23, 12:50 PM MST to 1:10 PM MST
Where: Maricopa County, 4.53 mi ESE of New River to 4.21 mi ESE of New River
Cause: Heavy Rain
Reported by: Mesonet
Coordinates: 33.902, -112.054

The Flood Control District of Maricopa County streamflow gage on Cline Creek near Jenny Lin Road and 12th Street exceeded alarm stage at 1250MST and bank full at 1254MST. Flow crested at 6.9 feet at 1255MST and fell back below alarm stage at 1307MST. No injuries or damages were reported.

Flash Flood, Maricopa

When: July 23, 12:50 PM MST to 6:00 PM MST
Where: Maricopa County, 2.84 mi ENE of New River to 2.56 mi ENE of New River
Cause: Heavy Rain
Property damage: $20,000
Reported by: Public
Coordinates: 33.929, -112.082

Very heavy rain fell in the afternoon with over 2 inches measured in the Anthem and New River area with radar estimates up to 4 inches over the New River Mesa between 1200MST and 1400MST. A social media video taken around 1400MST showed a few feet of rapid moving water running within Skunk Creek with an unoccupied SUV flowing downstream near Fig Springs Road. Timing of when flooding began estimated from radar and streamflow gages. No injuries were reported.

Flash Flood, Maricopa

When: July 23, 1:05 PM MST to 6:15 PM MST
Where: Maricopa County, 3.96 mi SE of New River to 4.57 mi SE of New River
Cause: Heavy Rain
Reported by: Department of Highways
Coordinates: 33.876, -112.085

Significant flood water moving downstream within Skunk Creek led to the closure of the low water crossing along Honda Bow Road between 7th Avenue and 9th Avenue. Time estimated from streamflow gages and radar. No damages or injuries reported.

Flash Flood, Maricopa

When: July 23, 1:15 PM MST to 6:30 PM MST
Where: Maricopa County, 5.53 mi SSE of New River to 5.87 mi SSE of New River
Cause: Heavy Rain
Reported by: Mesonet
Coordinates: 33.847, -112.092

A Flood Control District of Maricopa County streamflow gage along Skunk Creek at Desert Hills Drive exceeded alarm stage around 1315MST and bank full around 1325MST. Streamflow crested around 5.81 feet at 1329MST and was back below action stage by 1800MST. At 1805MST Maricopa County Department of Transportation reported 19th Avenue was closed between Desert Hills Drive and Irvine Road due to flooding. No damages or injuries were reported.

Flash Flood, Maricopa

When: July 23, 1:30 PM MST to 5:30 PM MST
Where: Maricopa County, 6.61 mi W of Cave Creek to 6.8 mi W of Cave Creek
Cause: Heavy Rain
Property damage: $40,000
Reported by: Law Enforcement
Coordinates: 33.815, -112.064

Video from Maricopa County Sheriff's Office showed two individuals being rescued via helicopter from the roof of a delivery truck that became stranded in a flooded wash near 7th street and Cloud Road. The two individuals were uninjured. The chopper footage also showed at least one home with roughly 1 to 2 fee of water surrounding it. No additional info provided on any impacted homes. Another video near 12th Street and Carefree Highway showed several inches of water flowing down 12th Street. An individual had to be rescued from their car after it became stranded in the flood water. The individual was uninjured, but the vehicle was lost.

Flash Flood, Maricopa

When: July 23, 2:00 PM MST to 6:00 PM MST
Where: Maricopa County, 7.44 mi S of New River to 8.48 mi S of New River
Cause: Heavy Rain
Reported by: Public
Coordinates: 33.813, -112.121

Skunk Creek experienced a significant rise after 2 to 4 inches of rain fell over the area and upstream. At 1400MST the the streamflow gage on Skunk Creek at Carefree Highway exceeded alarm stage. The gage then exceeded bank full at 1410MST and exceeded flood stage at 1418MST. Flow crested at 6.87 feet at 1426MST and would remain above alarm stage until 1715MST. A video posted at 1307MST on social media showed significant flow and debris over Dove Valley Road between I-17 and North Valley Parkway. Maricopa County Department of Transportation reported 27th Avenue was closed between Cloud Road and Dolores Road. No damages or injuries were reported.

Flash Flood, Maricopa

When: July 23, 2:10 PM MST to 4:45 PM MST
Where: Maricopa County, 5.86 mi NE of New River to 4.04 mi NE of New River
Cause: Heavy Rain
Property damage: $10,000
Reported by: Department of Highways
Coordinates: 33.979, -112.056

A streamflow gage on New River near Table Mesa Road exceeded alarm stage at 1404MST, bank full at 1419MST, and flood stage at 1422MST. The flood wave crested at 7.88 feet at 1426MST and remained above alarm stage until 1620MST. Three individuals were rescued by Maricopa County Sheriff's Office via helicopter after their SUV stalled in the flood waters near Table Mesa Road. A low water crossing roughly 7 miles downstream along Old Stage Road, north of New River Road, experienced significant flow and the road had to be closed. No injuries were reported.

Flash Flood, Maricopa

When: July 23, 3:00 PM MST to 4:30 PM MST
Where: Maricopa County, 6.81 mi E of Carefree to 7.83 mi E of Carefree
Cause: Heavy Rain / Burn Area
Reported by: Park/Forest Service
Coordinates: 33.895, -111.811

U.S. Forest Service reported a 4 foot rise in Camp Creek with flow originating from the Sears burn scar. Time estimated from radar. No damages or injuries were reported.

What these are

Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Lightning: A lightning strike that killed, injured or caused damage.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Arizona in 2021 Every state in 2021 This day in weather history Warnings in Arizona, July 2021

Sources

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: 986969, 976656, 976655, 976263, 976264, 976639, 976643, 976648, 976649, 976650, 976651, 976652, 977020, 977062, 977082, 977072, 977112, 977109, 977111, 977418, 977447, 977430, 977115, 977434, 977439, 977433.