Alert archive / Arizona / Flash Flood Warnings in 2026

Flash Flood Warning 26, NWS Las Vegas, NV

August 12, 2026Mohave County, Arizona; San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 12, 2026, 8:04 PM MST for Mohave County, Arizona; San Bernardino County, California. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 12, 2026, 8:04 PM MST (03:04 UTC)
Expired
Aug 12, 2026, 11:00 PM MST
In force
3 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Mohave County, AZ, San Bernardino County, CA

The radar

The Las Vegas radar (KESX), 106 km from the middle of the area, began a volume at 03:06 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 3.1 hours before the alert went out and 257 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Flgstf/Belemont, AZ at 00:00Z on 2026-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 150 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 00:00Z on 2026-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -11 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
150 J/kg
Mixed-layer CIN
-27 J/kg
Mixed-layer LCL
1202 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-11 m²/s²
0-3 km storm-relative helicity
-14 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

869 
WGUS55 KVEF 130304
FFWVEF
AZC015-CAC071-130600-
/O.NEW.KVEF.FF.W.0026.260813T0304Z-260813T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
804 PM PDT Wed Aug 12 2026

The National Weather Service in Las Vegas has issued a

* Flash Flood Warning for...
  Southwestern Mohave County in northwestern Arizona...
  San Bernardino County in southern California...

* Until 1100 PM PDT /1100 PM MST/.

* At 804 PM PDT /804 PM MST/, Doppler radar indicated thunderstorms
  producing heavy rain across the warned area. Between 0.5 and 1.5
  inches of rain have fallen. Additional rainfall amounts of 0.5 to 1
  inch are possible in the warned area. Flash flooding is ongoing or
  expected to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms producing
           flash flooding.

  SOURCE...Radar indicated.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Lake Havasu City, Topock, Yucca, Desert Hills, Arizona Village,
  Mohave Valley, Mojave Ranch Estates, Mesquite Creek, Oatman and
  Willow Valley.

This includes the following highways...
Interstate 40 in Arizona between mile markers 0 and 30. Interstate 40
in California between mile markers 153 and 155.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.

&&

LAT...LON 3501 11464 3509 11432 3482 11402 3464 11398
      3446 11455 3444 11494 3447 11501 3467 11483
      3473 11450 3477 11455 3484 11460 3487 11463
      3500 11464 3500 11463

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

JP
2 follow-up statements
809 
WGUS75 KVEF 130413
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
913 PM PDT Wed Aug 12 2026

AZC015-CAC071-130600-
/O.CON.KVEF.FF.W.0026.000000T0000Z-260813T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-San Bernardino CA-
913 PM PDT Wed Aug 12 2026 /913 PM MST Wed Aug 12 2026/

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 11 PM PDT /11 PM MST/
THIS EVENING FOR SOUTHWESTERN MOHAVE AND SAN BERNARDINO COUNTIES...

At 913 PM PDT /913 PM MST/, Doppler radar indicated thunderstorms
producing heavy rain across the warned area. Between 0.5 and 1.5
inches of rain have fallen. Additional rainfall amounts of 0.25 to
0.5 inches are possible in the warned area. Flash flooding is ongoing
or expected to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar indicated.

IMPACT...Life threatening flash flooding of creeks and streams, urban
         areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Lake Havasu City, Topock, Yucca, Desert Hills, Arizona Village,
  Mohave Valley, Mojave Ranch Estates, Mesquite Creek, Oatman and
  Willow Valley.

This includes the following highways...
Interstate 40 in Arizona between mile markers 0 and 30. Interstate 40
in California between mile markers 153 and 155.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.

&&

LAT...LON 3501 11464 3509 11432 3482 11402 3464 11398
      3446 11455 3444 11494 3447 11501 3467 11483
      3473 11450 3477 11455 3484 11460 3487 11463
      3500 11464 3500 11463

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

JP
342 
WGUS75 KVEF 130559
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1059 PM PDT Wed Aug 12 2026

AZC015-CAC071-130609-
/O.EXP.KVEF.FF.W.0026.000000T0000Z-260813T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-San Bernardino CA-
1059 PM PDT Wed Aug 12 2026 /1059 PM MST Wed Aug 12 2026/

...FLASH FLOOD WARNING WILL EXPIRE AT 11 PM PDT /11 PM MST/ THIS
EVENING FOR SOUTHWESTERN MOHAVE AND SAN BERNARDINO COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.

A Flood Watch remains in effect until 1200 AM PDT /1200 AM MST/ for a
portion of northwest Arizona.

&&

LAT...LON 3501 11464 3509 11432 3482 11402 3464 11398
      3446 11455 3444 11494 3447 11501 3467 11483
      3473 11450 3477 11455 3484 11460 3487 11463
      3500 11464 3500 11463

$$

Planz

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Las Vegas, NV wrote its last area forecast discussion before this flash flood warning went out at Aug 12, 4:36 PM MST, 3 hours 28 minutes earlier. Its key messages:

  • * This afternoon offers widespread chances for storms with an increased risk for flooding in Mohave County AZ, with a Flash Flood Watch issued from noon through midnight. * Daily afternoon to evening isolated thunderstorm chances will continue through the late week, with the greatest chances over higher terrain and some storms spreading into adjacent valleys.
Area forecast discussion, Aug 12, 4:36 PM MST, 3 hours 28 minutes before
Area Forecast Discussion
National Weather Service Las Vegas NV
436 PM PDT Wed Aug 12 2026

.KEY MESSAGES...

* This afternoon offers widespread chances for storms with an
  increased risk for flooding in Mohave County AZ, with a Flash
  Flood Watch issued from noon through midnight.

* Daily afternoon to evening isolated thunderstorm chances will
  continue through the late week, with the greatest chances over
  higher terrain and some storms spreading into adjacent valleys.

&&

.DISCUSSION...Through Tuesday.

Today is shaping up to be one of the most active monsoon days of
the season thus far. Latest SPC mesoanalysis shows the 1" PWAT
contour extending all the way up into the southern Great Basin.
With mostly sunny skies west of the Colorado River and a subtle
trough approaching off the Pacific, all the ingredients are there
for scattered storms across the area. Main concerns will be flash
flooding and gusty outflow winds. Morning convection in central
Mohave County produced impressive rain rates/totals, but will
likely limit (or at least delay) additional activity in this area
as the atmosphere has been worked over. This could set up an
instability gradient for afternoon storms to run along, pushing
them down the lower Colorado River Valley. SPC has highlighted
this area with a marginal risk of severe winds. Activity may
linger in the southern Great Basin and lower Colorado River Valley
this evening, but things should largely be on the downtrend
around sunset.

Tomorrow, the trough moves a bit closer and flow aloft
strengthens. This will speed up storm movement, reducing the
risk of flash flooding outside of training storms. However, this
stronger flow aloft will also produce an uptick in vertical wind
shear, potentially allowing for more organized convection. This
signal is most clear in the southern Great Basin where the latest
HREF indicates 70-90% probabilities of 30+ knot thunderstorm winds
and a 10-20% chance of 50+ knots. Wouldn't rule out the potential
for hail as well thanks to modestly rotating updrafts depicted in
some CAMs. Storm coverage across the Mojave Desert should be more
isolated in nature on Thursday. On Friday, the southwesterly flow
pushes moisture mainly into southeastern NV and northwestern AZ,
where isolated to scattered convection is yet again possible in
the afternoon hours. Drier conditions with just isolated activity
possible over the weekend.

&&

.AVIATION...For Harry Reid...For the 00Z Forecast Package...The
initial round of thunderstorms has pushed to the east. There is
still a 30% probability of additional showers and thunderstorms
during the evening hours. Thunderstorms at the terminals could
result in brief heavy rain, visibility under 5SM, sudden gusty
winds, and CIGs below 8000ft. Easterly winds will become southerly
after sunset and then become light and variable overnight. VFR
conditions with SCT-BKN clouds over 10kft are expected overnight.
Southerly winds will develop on Thursday afternoon with gusts to
around 25 kts. There is a 20-30% chance of thunderstorms on Thursday
afternoon with brief heavy rain, sudden gusts winds and CIGs below
8000 feet.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 00Z Forecast Package...Scattered showers and
thunderstorms will continue through at least sunset. Any storms
could produce lightning, heavy rain, sudden gusty winds, and CIGs
below 8000ft. Outside of convective influences, south to southwest
winds around 10-15 kts will diminish during the evening hours. South
to southwest winds will develop Thursday afternoon with gusts
generally at 15 to 25 kts. Although coverage will be less,
thunderstorms will develop again on Thursday afternoon.

&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.

&&

DISCUSSION...Woods
AVIATION...Czyzyk

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter

In the hours before

Local storm report, Aug 12, 3:41 PM MST, 4 hours 23 minutes before
Preliminary Local Storm Report
National Weather Service Las Vegas NV
341 PM PDT Wed Aug 12 2026

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

0203 PM     Tstm Wnd Gst     Nellis AFB              36.23N 115.03W
08/12/2026  M71 MPH          Clark              NV   ASOS

            KLSV reported a peak wind of 71 MPH.

&&

AN
Local storm report, Aug 12, 4:32 PM MST, 3 hours 32 minutes before
Preliminary Local Storm Report
National Weather Service Las Vegas NV
432 PM PDT Wed Aug 12 2026

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

0415 PM     Tstm Wnd Gst     1 N Desert Hills        34.57N 114.37W
08/12/2026  M61 MPH          Mohave             AZ   AWOS

            AWOS station KHII Lake Havasu City Airport.

&&
Local storm report, Aug 12, 4:37 PM MST, 3 hours 27 minutes before
Preliminary Local Storm Report
National Weather Service Las Vegas NV
437 PM PDT Wed Aug 12 2026

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

0600 PM     Flash Flood      8 WSW Mountain Pass     35.44N 115.67W
08/11/2026                   San Bernardino     CA   Public

            Images taken by Mojave National Park Service
            personnel show mud and debris covering Cima
            Rd just south of Interstate 15. Debris is
            estimated to be 1 to 2 feet deep. Time is
            estimated based on radar.

&&

ASG
Local storm report, Aug 12, 4:58 PM MST, 3 hours 6 minutes before
Preliminary Local Storm Report
National Weather Service Las Vegas NV
458 PM PDT Wed Aug 12 2026

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

0330 PM     Flash Flood      6 ENE New Kingman-Butle 35.30N 113.93W
08/12/2026                   Mohave             AZ   Public

            Images and videos show flash flooding along
            Route 66 between Kingman Airport and Valle
            Vista. Time is estimated based on radar.

&&

ASG

The office that day

Everything else NWS Las Vegas, NV issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 13, 9:36 AM MSTFlood WatchVEFMohave34 hr
Aug 13, 2:04 PM MSTSevere Thunderstorm WarningVEFMohave41 min
Aug 12, 6:02 PM MSTAreal Flood AdvisoryVEFSan Bernardino3 hr
Aug 12, 6:39 PM MSTFlash Flood Warning Considerable damage threatVEFSan Bernardino3 hr
Aug 13, 12:07 PM MSTSevere Thunderstorm WarningVEFSan Bernardino38 min
Aug 13, 12:43 PM MSTSevere Thunderstorm WarningVEFSan Bernardino47 min
Aug 13, 1:23 PM MSTFlash Flood Warning Considerable damage threatVEFSan Bernardino3 hr
Aug 13, 1:36 PM MSTAreal Flood AdvisoryVEFInyo3 hr
Aug 13, 2:13 PM MSTAreal Flood AdvisoryVEFInyo3 hr

Nearby

Flash Flood Warnings in Arizona, 2026Flash Flood Warnings in California, 2026Every flash flood warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.