Flash Flood and Debris Flow in Colorado, August 2, 2023

Name: Flash Flood and Debris Flow in Colorado, August 2, 2023
Start: 2023-08-02T13:15
End: 2023-08-02T21:50
Location: Colorado

August 2, 2023 · NWS GJT · 5 events in 5 counties and zones

Abundant monsoon moisture remained across Western Colorado. This led to another round of showers and thunderstorms across much of the region.

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: None recorded
Crop damage: None recorded
Events: 5

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 GJT wrote it up.

Abundant monsoon moisture remained across Western Colorado. This led to another round of showers and thunderstorms across much of the region. Storms were slow moving and produced heavy rain. As a result of the heavy rain, some flash flooding and debris flows occurred in Mesa and Eagle counties. Additionally, gusty outflow winds in excess of 58 mph occurred across portions of the Western Slope. The passage of a weak trough across northwest Colorado resulted in some stronger storms. One storm in Routt County produced a funnel cloud.

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 Grand Junction, CO wrote its last area forecast discussion before the first event at Aug 2, 10:50 AM MST, 2 hours 25 minutes earlier.

Area forecast discussion, Aug 2, 10:50 AM MST, 2 hours 25 minutes before

Area Forecast Discussion
National Weather Service Grand Junction CO
1150 AM MDT Wed Aug 2 2023

.SHORT TERM...(Today through Thursday)
Issued at 228 AM MDT Wed Aug 2 2023

As has occurred the last several nights during this monsoonal push,
showers and storms have lingered well into the night. This area of
precipitation will continue to drift off to the northeast and
diminish over the next few hours with clearing skies behind it. The
first in a series of shortwaves will be moving northeast through the
Great Basin over today, adding some extra energy and an improved
shear profile across eastern Utah and into northwest Colorado this
afternoon. That combined with some increased sunshine this morning
and the deep monsoonal mositure will mean the potential for some
rather robust storms this afternoon. Expect showers and storms to
fire off the terrain during the late morning or early afternoon,
with the best organization expected in Utah. These storms will
likely still be efficient rainers thanks to the deep moisture and
saturated atmosphere, capable of producing rainfall rates in
excess of an inch per hour. Other threats include gusty winds,
frequent lightning, and some small hail in the better organized
storms. The second in the aforementioned series of shortwaves is
projected to move through overnight tonight, which will help keep
convection rolling into the overnight, before lifting north into
Wyoming tomorrow morning.

This point marks a transition out of this monsoonal pattern and back
to a drier and warmer pattern. The subtropical high that has been
over the Southern Plains for the last few days will spread westward
starting late today, with drier air advecting northward by tomorrow
morning. This combined with the subsidence on the backside of the
shortwave trough progged to be over Wyoming will decrease shower and
storm coverage for tomorrow afternoon. The storms that do form over
the terrain will still be capable of producing brief heavy rain,
gusty winds, frequent lightning, and some small hail. The northern
half of the area will see the best activity.

Temperatures will remain near to a few degrees below normal for
today and tomorrow, but a gradual warming trend to near or
slightly above normal temperatures is on the horizon as
conditions dry out.

.LONG TERM...(Thursday night through Tuesday)
Issued at 228 AM MDT Wed Aug 2 2023

The low over Wyoming will track slowly eastward overnight with a
shallow trough at its base helping to sustain showers/thunderstorms
across northwest Colorado in the evening. During the remainder of
the period, high pressure will extend from the Gulf of Mexico to the
eastern Pacific effectively blocking any avenue for subtropical
moisture to enter the region. This will leave a dry, zonal flow
across the forecast area. A shallow ridge sets up Friday which
models indicated will persist through the weekend. Then, early next
week upper level winds shift to the northwest in response to a
shallow shortwave trough pushing across the northern High Plains.
This shift doesn't seem to alter conditions across the area which
are expected to be mostly dry in the valleys with isolated/low end
scattered afternoon/evening showers and thunderstorms each day with
the ranges along the Continental Divide and the eastern Uinta
Mountains favored. Given the prevailing zonal flow, temperatures are
expected to hover right around normal throughout the extended period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1150 AM MDT Wed Aug 2 2023

Thunderstorms are just getting started over the higher terrain
late this morning. The storms will gradually move northward off
the terrain into the valleys when they could impact TAF sites.
Stronger more organized storms are forecast to move out of central
Utah into our CWA by early evening with a complex of storms
drifting eastward through the evening and early morning hours. So
there will be periods of storms and this was attempted to be
relayed in the forecasts. However things are likely to change and
amendments will be issued as necessary. Gusty winds and brief
heavy rainfall rates could drop conditions to ILS and possibly
MVFR if a storm were to move over the airfield directly. KEGE did
see some lower clouds due to precipitation and that is a
probability for tomorrow morning as well. Otherwise VFR will
prevail at areas outside of thunderstorm threats.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

SHORT TERM...BGB
LONG TERM...NL
AVIATION...GJT

Hazardous weather outlook, Aug 2, 1:39 AM MST, 11 hours 36 minutes before

Hazardous Weather Outlook
National Weather Service Grand Junction CO
239 AM MDT Wed Aug 2 2023

COZ001>014-017>023-UTZ022>025-027>029-030845-
Lower Yampa River Basin-Central Yampa River Basin-
Roan and Tavaputs Plateaus-Elkhead and Park Mountains-
Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor-
Central Colorado River Basin-Grand and Battlement Mesas-
Gore and Elk Mountains/Central Mountain Valleys-
Central Gunnison and Uncompahgre River Basin-
West Elk and Sawatch Mountains-Flat Tops-
Upper Gunnison River Valley-Uncompahgre Plateau and Dallas Divide-
Northwest San Juan Mountains-Southwest San Juan Mountains-
Paradox Valley/Lower Dolores River-
Four Corners/Upper Dolores River-Animas River Basin-
San Juan River Basin-Southeast Utah-Eastern Uinta Mountains-
Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat-
La Sal and Abajo Mountains-Canyonlands/Natural Bridges-
239 AM MDT Wed Aug 2 2023

This hazardous weather outlook is for eastern Utah and western
Colorado.

.DAY ONE...Today and Tonight

Today will be the last day of truly monsoon like convection, with
heavy rain and frequent lightning still the main threats, followed
by small hail and gusty winds. Rainfall rates in excess of an inch
an hour are possible. As with the last several days, activity will
last well into the overnight.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Drier air begins to work in on Thursday, decreasing shower and
storm coverage somewhat. It will also lead to a transition away
from heavy rain producing storms to storms more likely to produce
gusty outflow winds. Frequent lightning remains a threat with any
storm. Temperatures will also begin to slowly warm to near or a
few degrees above normal by the weekend.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

In the hours before

Local storm report, Aug 2, 9:05 AM MST, 4 hours 10 minutes before

Preliminary Local Storm Report
National Weather Service Grand Junction CO
1005 AM MDT Wed Aug 2 2023

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

0700 AM     Rain             2 W Redlands            39.09N 108.69W
08/02/2023  M1.61 inch       Mesa               CO   Cocorahs

            Cocorahs station CO-ME-180 Grand Junction
            7.2 W. The period of the Rain event was 24
            hours.

1100 AM     Rain             3 SSW Coal Bank Pass    37.66N 107.80W
08/01/2023  M1.40 inch       San Juan           CO   Mesonet

            Mesonet station CADC2 3.3 SW Coal Bank Pass
            (SNOTEL). The period of the Rain event was
            24 hours.

0700 AM     Rain             4 W Cattle Creek        39.44N 107.31W
08/02/2023  M1.40 inch       Garfield           CO   Cocorahs

            Cocorahs station CO-GF-73 Glenwood Springs
            7.2S. The period of the Rain event was 24
            hours.

0815 AM     Rain             1 SSE Minturn           39.57N 106.41W
08/02/2023  M1.33 inch       Eagle              CO   Mesonet

            Mesonet station CSSC2 1.3 SE Minturn
            (CBRFC). The period of the Rain event was 24
            hours.

0945 AM     Rain             3 E Milner              40.49N 106.96W
08/01/2023  M1.30 inch       Routt              CO   Mesonet

            Mesonet station FW5702 Steamboat Springs.
            The period of the Rain event was 24 hours.

1100 AM     Rain             3 E Skyway              39.06N 108.06W
08/01/2023  M1.30 inch       Mesa               CO   Mesonet

            Mesonet station MESC2 3.4 E Skyway (SNOTEL).
            The period of the Rain event was 24 hours.

1000 AM     Rain             4 S Sawpit              37.93N 108.01W
08/01/2023  M1.20 inch       San Miguel         CO   Mesonet

            Mesonet station GW1216 Sawpit. The period of
            the Rain event was 24 hours.

0845 AM     Rain             1 SSW Slater            40.98N 107.38W
08/02/2023  M1.20 inch       Moffat             CO   Mesonet

            Mesonet station SLFC2 1.4 SW Slater (CBRFC).
            The period of the Rain event was 24 hours.

0857 AM     Rain             7 ENE Toponas           40.10N 106.68W
08/02/2023  M1.11 inch       Routt              CO   Mesonet

            Mesonet station PCPC2 Porcupine Crk, Toponas
            6ENE. The period of the Rain event was 24
            hours.

0955 AM     Rain             1 E Mount Crested Butte 38.91N 106.96W
08/01/2023  M1.09 inch       Gunnison           CO   Mesonet

            Mesonet station FW1025 Mt. Crested Butte.
            The period of the Rain event was 24 hours.

0700 AM     Rain             4 E Cattle Creek        39.46N 107.18W
08/02/2023  M1.04 inch       Garfield           CO   Cocorahs

            Cocorahs station CO-GF-49 Carbondale 4.6NNE.
            The period of the Rain event was 24 hours.

1153 AM     Rain             3 SSE Woody Creek       39.23N 106.87W
08/01/2023  M1.03 inch       Pitkin             CO   ASOS

            ASOS station KASE Aspen-Pitkin Cnty Airport.
            The period of the Rain event was 24 hours.

0706 AM     Rain             4 WNW Cattle Creek      39.46N 107.32W
08/02/2023  M1.02 inch       Garfield           CO   Cocorahs

            Cocorahs station CO-GF-88 Glenwood Springs
            5.9 S. The period of the Rain event was 24
            hours.

0700 AM     Rain             2 ENE Vail              39.65N 106.33W
08/02/2023  M0.92 inch       Eagle              CO   Cocorahs

            Cocorahs station CO-EG-19 Vail 2.6E. The
            period of the Rain event was 24 hours.

1200 PM     Rain             17 N Maeser             40.72N 109.54W
08/01/2023  M0.90 inch       Uintah             UT   Mesonet

            Mesonet station KGCU1 16.9 N Maeser
            (SNOTEL). The period of the Rain event was
            24 hours.

0800 AM     Rain             11 W De Beque           39.33N 108.42W
08/02/2023  M0.90 inch       Mesa               CO   Mesonet

            Mesonet station WETC2 11.0 W De Beque (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
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            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2). The period of
            the Rain event was 24 hours.

0800 AM     Rain             18 E Buford             40.00N 107.24W
08/02/2023  M0.90 inch       Garfield           CO   Mesonet

            Mesonet station TLSC2 18.2 E Buford
            (SNOTEL). The period of the Rain event was
            24 hours.

0911 AM     Rain             6 W Grand Mesa          39.03N 107.98W
08/01/2023  M0.84 inch       Delta              CO   Mesonet

            Mesonet station TT695 Grand Mesa. The period
            of the Rain event was 24 hours.

0700 AM     Rain             3 NW Cattle Creek       39.48N 107.29W
08/02/2023  M0.82 inch       Garfield           CO   Cocorahs

            Cocorahs station CO-GF-33 Glenwood Springs
            5.3SSE. The period of the Rain event was 24
            hours.

1100 AM     Rain             8 SW Yampa              40.06N 107.01W
08/01/2023  M0.80 inch       Routt              CO   Mesonet

            Mesonet station BRRC2 8.3 SW Yampa (SNOTEL).
            The period of the Rain event was 24 hours.

0700 AM     Rain             7 E Toponas             40.08N 106.67W
08/02/2023  M0.80 inch       Routt              CO   Mesonet

            Mesonet station LYNC2 6.9 E Toponas
            (SNOTEL). The period of the Rain event was
            24 hours.

0650 AM     Rain             Carbondale              39.40N 107.22W
08/02/2023  M0.77 inch       Garfield           CO   Cocorahs

            Cocorahs station CO-GF-47 Carbondale 0.5W.
            The period of the Rain event was 24 hours.

0853 AM     Rain             Meeker                  40.05N 107.88W
08/02/2023  M0.77 inch       Rio Blanco         CO   ASOS

            ASOS station KEEO Meeker Airport. The period
            of the Rain event was 24 hours.

0856 AM     Rain             2 N Dowd                39.63N 106.45W
08/02/2023  M0.77 inch       Eagle              CO   Mesonet

            Mesonet station DJTC2 Dowd Junction. The
            period of the Rain event was 24 hours.

0855 AM     Rain             4 NNW Burns             39.92N 106.92W
08/02/2023  M0.76 inch       Eagle              CO   Mesonet

            Mesonet station STHC2 Hangman, Burns 3NW.
            The period of the Rain event was 24 hours.

1200 PM     Rain             6 N Rifle               39.63N 107.76W
08/01/2023  M0.75 inch       Garfield           CO   Mesonet

            Mesonet station RRGC2 6.2 N Rifle. The
            period of the Rain event was 24 hours.

0855 AM     Rain             14 NNW New Castle       39.77N 107.65W
08/02/2023  M0.74 inch       Garfield           CO   Mesonet

            Mesonet station MITC2 Deep Crk, NewCastle
            14NNW. The period of the Rain event was 24
            hours.

0941 AM     Rain             8 WNW Rifle             39.59N 107.92W
08/01/2023  M0.72 inch       Garfield           CO   Mesonet

            Mesonet station TT532 Roan Plateau. The
            period of the Rain event was 24 hours.

1100 AM     Rain             6 ESE Meridith          39.32N 106.61W
08/01/2023  M0.70 inch       Pitkin             CO   Mesonet

            Mesonet station KLNC2 6.1 E Meridith
            (SNOTEL). The period of the Rain event was
            24 hours.

0700 AM     Rain             18 S Manila             40.74N 109.67W
08/02/2023  M0.70 inch       Uintah             UT   Mesonet

            Mesonet station TCKU1 17.7 S Manila
            (SNOTEL). The period of the Rain event was
            24 hours.

0700 AM     Rain             4 WSW Buford            39.97N 107.64W
08/02/2023  M0.70 inch       Rio Blanco         CO   Cocorahs

            Cocorahs station CO-RB-18 Meeker 14.3ESE.
            The period of the Rain event was 24 hours.

0925 AM     Rain             9 N Meridith            39.48N 106.73W
08/01/2023  M0.67 inch       Eagle              CO   Mesonet

            Mesonet station ESLC2 9.2 N Meridith. The
            period of the Rain event was 24 hours.

0718 AM     Rain             1 W Edwards             39.65N 106.62W
08/02/2023  M0.67 inch       Eagle              CO   Cocorahs

            Cocorahs station CO-EG-3 Edwards 1.3WNW. The
            period of the Rain event was 24 hours.

0722 AM     Rain             1 W Edwards             39.65N 106.62W
08/02/2023  M0.67 inch       Eagle              CO   CO-OP Observer

            CO-OP Observer station EDRC2 Edwards 1WNW.
            The period of the Rain event was 24 hours.

0700 AM     Rain             2 NW Glenwood Springs   39.57N 107.35W
08/02/2023  M0.66 inch       Garfield           CO   Cocorahs

            Cocorahs station CO-GF-40 Glenwood Springs
            1.7NW. The period of the Rain event was 24
            hours.

0700 AM     Rain             1 NNW Carbondale        39.41N 107.22W
08/02/2023  M0.62 inch       Garfield           CO   Cocorahs

            Cocorahs station CO-GF-85 Carbondale 0.7
            NNW. The period of the Rain event was 24
            hours.

0700 AM     Rain             1 S Glenwood Springs    39.53N 107.33W
08/02/2023  M0.61 inch       Garfield           CO   Cocorahs

            Cocorahs station CO-GF-89 Glenwood Springs
            0.8 S. The period of the Rain event was 24
            hours.

0700 AM     Rain             2 W Vail                39.65N 106.40W
08/02/2023  M0.61 inch       Eagle              CO   Cocorahs

            Cocorahs station CO-EG-21 Vail 0.9WNW. The
            period of the Rain event was 24 hours.

0955 AM     Rain             14 NNW New Castle       39.77N 107.65W
08/01/2023  M0.60 inch       Garfield           CO   Mesonet

            Mesonet station MITC2 Deep Crk, NewCastle
            14NNW. The period of the Rain event was 24
            hours.

1100 AM     Rain             Coal Bank Pass          37.70N 107.78W
08/01/2023  M0.60 inch       San Juan           CO   Mesonet

            Mesonet station SPSC2 Coal Bank Pass
            (SNOTEL). The period of the Rain event was
            24 hours.

0915 AM     Rain             1 SSE Minturn           39.57N 106.41W
08/01/2023  M0.59 inch       Eagle              CO   Mesonet

            Mesonet station CSSC2 1.3 SE Minturn
            (CBRFC). The period of the Rain event was 24
            hours.

0700 AM     Rain             Glenwood Springs        39.54N 107.33W
08/02/2023  M0.57 inch       Garfield           CO   Cocorahs

            Cocorahs station CO-GF-1 Glenwood Spgs
            0.64S. The period of the Rain event was 24
            hours.

0700 AM     Rain             Edwards                 39.65N 106.59W
08/02/2023  M0.54 inch       Eagle              CO   Cocorahs

            Cocorahs station CO-EG-52 Edwards 0.5 E. The
            period of the Rain event was 24 hours.

0927 AM     Rain             48 NE Elgin             39.50N 109.56W
08/01/2023  M0.52 inch       Uintah             UT   Mesonet

            Mesonet station WNTU1 Winter Ridge, Mack
            41WNW. The period of the Rain event was 24
            hours.

1127 AM     Rain             48 NE Elgin             39.50N 109.56W
08/01/2023  M0.52 inch       Uintah             UT   Mesonet

            Mesonet station WNTU1 Winter Ridge, Mack
            41WNW. The period of the Rain event was 24
            hours.

0845 AM     Rain             2 W Vail                39.64N 106.39W
08/02/2023  M0.52 inch       Eagle              CO   Mesonet

            Mesonet station GRVC2 1.9 W Vail (CBRFC).
            The period of the Rain event was 24 hours.

1100 AM     Rain             14 N Hahns Peak         41.00N 106.91W
08/01/2023  M0.50 inch       Routt              CO   Mesonet

            Mesonet station WPKW4 Whiskey Park. The
            period of the Rain event was 24 hours.

1100 AM     Rain             2 SW Vail               39.62N 106.38W
08/01/2023  M0.50 inch       Eagle              CO   Mesonet

            Mesonet station VLMC2 2.0 SW Vail (SNOTEL).
            The period of the Rain event was 24 hours.

1100 AM     Rain             13 ENE Mount Crested Bu 38.99N 106.75W
08/01/2023  M0.50 inch       Gunnison           CO   Mesonet

            Mesonet station UPTC2 14.6 S Aspen (SNOTEL).
            The period of the Rain event was 24 hours.

1100 AM     Rain             10 E Grand Co Arpt      38.48N 109.27W
08/01/2023  M0.50 inch       San Juan           UT   Mesonet

            Mesonet station LSMU1 11.6 NW La Sal
            (SNOTEL). The period of the Rain event was
            24 hours.

1100 AM     Rain             9 E Grand Co Arpt       38.48N 109.29W
08/01/2023  M0.50 inch       San Juan           UT   Mesonet

            Mesonet station LMLU1 8.6 E Grand Co Arpt
            (SNOTEL). The period of the Rain event was
            24 hours.

1100 AM     Rain             8 WNW Verdure           37.81N 109.49W
08/01/2023  M0.50 inch       San Juan           UT   Mesonet

            Mesonet station CJSU1 7.8 W Verdure
            (SNOTEL). The period of the Rain event was
            24 hours.

1100 AM     Rain             9 ENE Elk Park          37.71N 107.51W
08/01/2023  M0.50 inch       San Juan           CO   Mesonet

            Mesonet station BRTC2 8.9 E Elk Park
            (SNOTEL). The period of the Rain event was
            24 hours.

1100 AM     Rain             15 N Glenwood Springs   39.76N 107.36W
08/01/2023  M0.50 inch       Garfield           CO   Mesonet

            Mesonet station BLSC2 15.3 N Glenwood
            Springs (SNOTEL). The period of the Rain
            event was 24 hours.

1100 AM     Rain             2 SW Eagle-Vail         39.60N 106.51W
08/01/2023  M0.50 inch       Eagle              CO   Mesonet

            Mesonet station BCVC2 2.0 SW Eagle-Vail
            (SNOTEL). The period of the Rain event was
            24 hours.

1200 PM     Rain             8 WNW Verdure           37.81N 109.49W
08/01/2023  M0.50 inch       San Juan           UT   Mesonet

            Mesonet station CJSU1 7.8 W Verdure
            (SNOTEL). The period of the Rain event was
            24 hours.

0700 AM     Rain             Orchard Mesa            39.04N 108.52W
08/02/2023  M0.50 inch       Mesa               CO   Cocorahs

            Cocorahs station CO-ME-185 Grand Junction
            3.7 SSE. The period of the Rain event was 24
            hours.

0700 AM     Rain             6 W Monticello          37.87N 109.45W
08/02/2023  M0.50 inch       San Juan           UT   Mesonet

            Mesonet station BUCU1 6.1 W Monticello
            (SNOTEL). The period of the Rain event was
            24 hours.

0800 AM     Rain             8 WNW Verdure           37.81N 109.49W
08/02/2023  M0.50 inch       San Juan           UT   Mesonet

            Mesonet station CJSU1 7.8 W Verdure
            (SNOTEL). The period of the Rain event was
            24 hours.

0845 AM     Rain             2 W Vail                39.64N 106.39W
08/02/2023  M0.50 inch       Eagle              CO   Mesonet

            Mesonet station GRVC2 1.9 W Vail (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2) (R2)
            (R2) (R2) (R2) (R2) (R2) (R2). The period of
            the Rain event was 24 hours.

&&

Special weather statement, Aug 2, 12:32 PM MST, 43 minutes before

Special Weather Statement
National Weather Service Grand Junction CO
132 PM MDT Wed Aug 2 2023

COZ001>003-UTZ025-022015-
Roan and Tavaputs Plateaus CO-Lower Yampa River Basin CO-
Central Yampa River Basin CO-Tavaputs Plateau UT-
132 PM MDT Wed Aug 2 2023

...A strong thunderstorm will impact portions of west central Rio
Blanco County through 215 PM MDT...

At 132 PM MDT, Doppler radar was tracking a strong thunderstorm 22
miles southwest of Rangely, or 53 miles northwest of Grand Junction,
moving northeast at 25 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This storm will remain over mainly rural areas of west central Rio
Blanco County.

This includes the following highways...
 Colorado 64 between mile markers 17 and 22.
 Colorado 139 between mile markers 48 and 72.

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 3969 10905 3984 10918 4015 10876 3983 10852
TIME...MOT...LOC 1932Z 236DEG 21KT 3980 10897

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

KJS

Special weather statement, Aug 2, 12:48 PM MST, 27 minutes before

Special Weather Statement
National Weather Service Grand Junction CO
148 PM MDT Wed Aug 2 2023

COZ004-005-022015-
Upper Yampa River Basin CO-Elkhead and Park Mountains CO-
148 PM MDT Wed Aug 2 2023

...A strong thunderstorm will impact portions of southeastern Routt
County through 215 PM MDT...

At 147 PM MDT, Doppler radar was tracking a strong thunderstorm near
Yampa, or 45 miles southeast of Craig, moving northeast at 15 mph.

HAZARD...Winds in excess of 30 mph and pea 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.

This storm will remain over mainly rural areas of southeastern Routt
County.

This includes Colorado 131 between mile markers 41 and 45.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Conditions are favorable for the development of weak, brief funnel
clouds. This type of funnel cloud is harmless, but on rare occasions
they can briefly touch down, producing wind gusts over 50 mph. If a
funnel cloud is spotted move indoors and report your sighting to the
National Weather Service.

&&

LAT...LON 4015 10664 4008 10684 4018 10694 4036 10671
      4028 10663
TIME...MOT...LOC 1947Z 231DEG 12KT 4016 10684

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...30 MPH

KJS

Special weather statement, Aug 2, 1:09 PM MST, 6 minutes before

Special Weather Statement
National Weather Service Grand Junction CO
209 PM MDT Wed Aug 2 2023

COZ001>003-022045-
Roan and Tavaputs Plateaus CO-Lower Yampa River Basin CO-
Central Yampa River Basin CO-
209 PM MDT Wed Aug 2 2023

...A strong thunderstorm will impact portions of northwestern Rio
Blanco County through 245 PM MDT...

At 209 PM MDT, Doppler radar was tracking a strong thunderstorm near
Rangely, or 52 miles southeast of Vernal, moving northeast at 25 mph.

HAZARD...Winds in excess of 40 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.

This storm will remain over mainly rural areas of northwestern Rio
Blanco County, including the following locations... Massadona.

This includes the following highways...
 Colorado 64 between mile markers 18 and 40.
 Colorado 139 between mile markers 56 and 72.

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 3985 10882 4003 10893 4028 10853 3998 10833
TIME...MOT...LOC 2009Z 239DEG 22KT 4001 10874

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

KJS

The radar

The Grand Junction radar (KGJX), 165 km away, was scanning. The volume nearest the first event began at 20:16 UTC.

Open the radar archive at this moment

Event by event

2 thunderstorm wind, 1 funnel cloud, 1 flash flood, 1 debris flow. Local standard time, as filed.

Funnel Cloud, Routt

When: August 2, 1:15 PM MST
Where: Routt County, 0.87 mi SE of Yampa
Reported by: Public
Coordinates: 40.140, -106.890

A funnel cloud was spotted by several people near Yampa.

Flash Flood, Mesa

When: August 2, 5:00 PM MST to 5:20 PM MST
Where: Mesa County, 2.12 mi S of Fruita to 2.48 mi SSW of Fruita
Cause: Heavy Rain
Reported by: Park/Forest Service
Coordinates: 39.119, -108.731

The Colorado Department of Transportation reported flash flooding on Colorado Highway 340 at the west entrance to the Colorado National Monument. Up to 6 inches of water ran across the road as a result of heavy from thunderstorms. Additionally, some large boulder collapsed on the road as well as some mud. The superintendent of the Colorado National Monument also reported several inches of water flooded the Visitor's Center. Luckily, there were no injuries or damage to cars reported during the event. The rain gauge, located across from the Visitor's Center, recorded 0.90 inches of rain in 20 minutes.

Thunderstorm Wind, Montezuma

When: August 2, 5:44 PM MST
Where: Montezuma County, (Cez)cortez Arpt
Measured: 54 kt (62 mph) measured gust
Reported by: ASOS
Coordinates: 37.300, -108.630

A peak wind gust of 62 MPH was measured by the automated weather station at the Cortez Municipal Airport.

Thunderstorm Wind, Rio Blanco

When: August 2, 7:23 PM MST
Where: Rio Blanco County, 20.33 mi ESE of Rangely Arpt
Measured: 55 kt (63 mph) measured gust
Reported by: Mesonet
Coordinates: 40.020, -108.400

A peak wind gust of 63 MPH was measured by an automated weather station 18 miles southeast of Massadona.

Debris Flow, Eagle

When: August 2, 9:00 PM MST to 9:50 PM MST
Where: Eagle County, 0.91 mi S of El Jebel to 0.93 mi S of El Jebel
Cause: Heavy Rain / Burn Area
Reported by: Local Official
Coordinates: 39.387, -107.082

Strong thunderstorms sat over the Lake Christine Burn Scar with rain rates exceeding 1 inch per hour at times. As a result of heavy rain over the burn scar, there were reports of minor flooding in some townhomes. Additionally, the pedestrian underpass next to Whole Foods was filled with around 5.5 feet of water.

What these are

Funnel Cloud: A rotating column of cloud extending from a thunderstorm that did not reach the ground.
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.
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.
Debris Flow: A fast-moving slurry of mud, rock and debris, usually on a slope soaked by heavy rain or stripped by a fire.

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

The same day elsewhere

Every storm in Colorado in 2023 Every state in 2023 This day in weather history Warnings in Colorado, August 2023

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: 1105492, 1105493, 1105495, 1105494, 1105844.