Alert archive / Colorado / Flash Flood Warnings in 2026

Flash Flood Warning 21, NWS Grand Junction, CO

July 20, 2026Rio Blanco County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Jul 20, 2026, 8:04 PM MDT for Rio Blanco County, Colorado. 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
Jul 20, 2026, 8:04 PM MDT (02:04 UTC)
Expired
Jul 20, 2026, 11:00 PM MDT
In force
3 hr
Issued by
NWS Grand Junction, CO
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Rio Blanco County, CO

The radar

The Grand Junction radar (KGJX), 106 km from the middle of the area, began a volume at 02:02 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

Grand Junction, CO (KGJT), launched 00:00Z, 2.1 hours before the alert went out and 103 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, Grand Junction, CO at 00:00Z on 2026-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 951 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Grand Junction, CO at 00:00Z on 2026-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 46 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
951 J/kg
Mixed-layer CIN
-71 J/kg
Mixed-layer LCL
3249 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
46 m²/s²
0-3 km storm-relative helicity
103 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

602 
WGUS55 KGJT 210204
FFWGJT
COC103-210500-
/O.NEW.KGJT.FF.W.0021.260721T0204Z-260721T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
804 PM MDT Mon Jul 20 2026

The National Weather Service in Grand Junction has issued a

* Flash Flood Warning for...
  The Lee Burn Scar in...
  Central Rio Blanco County in northwestern Colorado...

* Until 1100 PM MDT.

* At 804 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Lee Burn Scar. Flash flooding is ongoing or 
  expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flows. 
The debris flow can consist of rock, mud, vegetation and other loose 
materials.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding in and around the Lee Burn
           Scar.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Lee Burn Scar.

* Some locations that will experience flash flooding include...
  mainly rural areas of Central Rio Blanco County

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause 
extensive and severe flash flooding of creeks...streams...and 
ditches in the Lee Burn Scar. Severe debris flows can also be 
anticipated across roads. Roads and driveways may be washed away in 
places. If you encounter flood waters...climb to safety.

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry arroyos is likely. The heavy rains 
will likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

&&

LAT...LON 4011 10820 4007 10810 4003 10807 4004 10793
      3987 10791 3986 10818 3994 10827 4006 10829

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

$$

TGR
1 follow-up statement
433 
WGUS75 KGJT 210455
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
1055 PM MDT Mon Jul 20 2026

COC103-210505-
/O.EXP.KGJT.FF.W.0021.000000T0000Z-260721T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Rio Blanco CO-
1055 PM MDT Mon Jul 20 2026

...FLASH FLOOD WARNING FOR THE LEE BURN SCAR WILL EXPIRE AT 11 PM 
MDT THIS EVENING FOR CENTRAL RIO BLANCO COUNTY...

Excess runoff from heavy rain has ended over the warned area. If 
flooding has been observed...Please report it to your local law 
enforcement agency. Flooding is no longer expected to pose a threat. 
Please continue to heed remaining road closures.

&&

LAT...LON 4011 10820 4007 10810 4003 10807 4004 10793
      3987 10791 3986 10818 3994 10827 4006 10829

$$

15

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 Grand Junction, CO wrote its last area forecast discussion before this flash flood warning went out at Jul 20, 5:25 PM MDT, 2 hours 39 minutes earlier. Its key messages:

  • Showers and storms will continue this week each afternoon and evening, with coverage becoming more widespread by Tuesday and Wednesday.
  • Primary threats include heavy rainfall, lightning, and outflow winds (30-40 mph). Some small hail will also be possible.
  • Storms have the ability to produce flash flooding and debris flows in vulnerable terrain, including areas near and downstream of burn scars.
Area forecast discussion, Jul 20, 5:25 PM MDT, 2 hours 39 minutes before
Area Forecast Discussion
National Weather Service Grand Junction CO
525 PM MDT Mon Jul 20 2026

.KEY MESSAGES...

- Showers and storms will continue this week each afternoon and
  evening, with coverage becoming more widespread by Tuesday and
  Wednesday.

- Primary threats include heavy rainfall, lightning, and outflow
  winds (30-40 mph). Some small hail will also be possible.

- Storms have the ability to produce flash flooding and debris
  flows in vulnerable terrain, including areas near and
  downstream of burn scars.

&&

.DISCUSSION...
Issued at 1102 AM MDT Mon Jul 20 2026

A stagnant high-pressure system remains parked over the area.
This is leading to many rinse and repeat days when it comes to
the current forecast. Shower and thunderstorm chances remain
each afternoon and evening, at least for the first half of the
week. Shower activity appears to become more widespread by
Tuesday and Wednesday as a shortwave rotates around the high
causing it to move to our southeast. This will allow PWATs to
increase to upwards of 200% of normal. Primary threats continue
to be heavy rainfall, lightning, and gusty outflow winds (35-45
mph). Small hail is also a possibility. With that being said,
depending on where these storms choose to materialize, they
introduce a threat for flash flooding and debris flows. This
remains a concern for areas with vulnerable terrain, including
recent burn scars in addition to burn scars from previous years.
For greater detail on the flash flooding risk, see the
hydrology section below.

By midweek, the high-pressure system will shift slightly,
altering our storm tracks. While storms have recently been
taking an unusual east-to-west path, the new pattern will likely
steer them up from the south and perhaps the west by late week.
After that shortwave passes to our north westerly flow becomes
established. This may alter the moisture across the area, which
in turn may change daily storm chances.

As far as temperatures are concerned, daytime highs will
continue to be above normal for the next few days, with near
normal temperatures expected Wednesday and beyond.

A special note for outdoor enthusiasts: Please continue to
monitor the forecast and adjust your plans as needed. These
storms can develop rapidly, bringing sudden hazards. Your best
bet is to head out early in the morning, as storm activity
typically strengthens in the afternoon. Always ensure you have
multiple ways to receive weather warnings.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 522 PM MDT Mon Jul 20 2026

Showers and thunderstorms are expected through the afternoon,
evening, and early portion of the night. Stronger storms may
bring localized heavy rain capable of dropping vis to MVFR, and
cigs below ILS breakpoints. Near thunderstorms, gusty and
variable winds up to 30 kts will be possible as well. Overnight,
storm coverage diminishes, leaving scattered cloud cover and
generally light winds. Storms return tomorrow afternoon with the
aforementioned threats again becoming possible.

&&

.HYDROLOGY...
Issued at 1102 AM MDT Mon Jul 20 2026

Anomalous moisture has become established across portions of
eastern Utah and western Colorado. Scattered thunderstorms capable
of producing heavy rain are expected this afternoon and early
evening. Rainfall rates of 1-2 inches per hour will be possible with
the stronger storms. These rates could lead to flash flooding and
debris flows especially over steep terrain and recent burn scars.
Also, rain over the past several days has lead to saturated soils,
which increase the chances for excessive runoff.

As a reminder: Keep an eye on our forecasts through the end of
the week and stay tuned for updated hydrology alerts if
visiting or if you reside below vulnerable terrain to flash
flooding and/or debris flows. Storms across the west develop
quickly, leaving little room for lead time in flashy terrain.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...None.
UT...None.

&&

DISCUSSION...TGJT
AVIATION...TGJT
HYDROLOGY...TGJT

In the hours before

Special weather statement, Jul 20, 6:33 PM MDT, 1 hour 31 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
633 PM MDT Mon Jul 20 2026

COZ002-003-007-009-010-013-210100-
Roan and Tavaputs Plateaus CO-Flat Tops CO-
Grand and Battlement Mesas CO-Debeque to Silt Corridor CO-
Gore and Elk Mountains/Central Mountain Valleys CO-
Central Yampa River Basin CO-
633 PM MDT Mon Jul 20 2026

...STRONG THUNDERSTORMS WILL IMPACT NORTH CENTRAL MESA...SOUTH
CENTRAL GARFIELD AND SOUTH CENTRAL RIO BLANCO COUNTIES THROUGH 700 PM
MDT...

At 633 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 18 miles north of New Castle to near Rifle to
13 miles south of Silt. Movement was west at 35 mph.

HAZARD...Wind gusts of 50 to 55 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Rifle, Silt, Parachute, Rio Blanco, and Battlement Mesa.

This includes the following highways...
 Interstate 70 in Colorado between mile markers 65 and 98.
 Colorado 13 between mile markers 1 and 29.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3990 10813 3954 10837 3926 10806 3932 10761
      3959 10765 3989 10770
TIME...MOT...LOC 0033Z 085DEG 32KT 3984 10762 3957 10783 3934 10764

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

BW
Local storm report, Jul 20, 6:34 PM MDT, 1 hour 30 minutes before
Preliminary Local Storm Report
National Weather Service Grand Junction CO
634 PM MDT Mon Jul 20 2026

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

0616 PM     Tstm Wnd Gst     2 E Rifle               39.53N 107.73W
07/20/2026  M58 MPH          Garfield           CO   ASOS

            ASOS station KRIL Garfield County Rgnl AP.

&&
Special weather statement, Jul 20, 6:59 PM MDT, 1 hour 5 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
659 PM MDT Mon Jul 20 2026

COZ006-007-009-210130-
Grand and Battlement Mesas CO-Debeque to Silt Corridor CO-
Grand Valley CO-
659 PM MDT Mon Jul 20 2026

...A STRONG THUNDERSTORM WILL IMPACT CENTRAL DELTA AND CENTRAL MESA
COUNTIES THROUGH 730 PM MDT...

At 658 PM MDT, Doppler radar was tracking a strong thunderstorm 13
miles southwest of Collbran, or 25 miles east of Grand Junction,
moving southwest at 20 mph.

HAZARD...Wind gusts of 50 to 55 mph and nickel size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Skyway.

This includes Colorado 65 between mile markers 24 and 49.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3918 10817 3906 10796 3888 10806 3907 10837
TIME...MOT...LOC 0058Z 034DEG 19KT 3907 10810

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH

LB
Special weather statement, Jul 20, 7:02 PM MDT, 1 hour 2 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
702 PM MDT Mon Jul 20 2026

COZ006-009-011-017-210130-
Grand and Battlement Mesas CO-Uncompahgre Plateau/Dallas Divide CO-
Grand Valley CO-Central Gunnison and Uncompahgre River Basin CO-
702 PM MDT Mon Jul 20 2026

...STRONG THUNDERSTORMS WILL IMPACT SOUTHWESTERN DELTA COUNTY THROUGH
730 PM MDT...

At 701 PM MDT, Doppler radar was tracking a cluster of strong
thunderstorms 8 miles west of Delta, or 24 miles northwest of
Montrose, moving south at 30 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Delta.

This includes U.S. Highway 50 in Colorado between mile markers 53 and
71.

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 3887 10830 3879 10805 3866 10811 3875 10838
TIME...MOT...LOC 0101Z 010DEG 27KT 3870 10822

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

LB
Special weather statement, Jul 20, 7:27 PM MDT, 37 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
727 PM MDT Mon Jul 20 2026

COZ006-009-011-017-210200-
Grand and Battlement Mesas CO-Uncompahgre Plateau/Dallas Divide CO-
Grand Valley CO-Central Gunnison and Uncompahgre River Basin CO-
727 PM MDT Mon Jul 20 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN DELTA AND SOUTH
CENTRAL MESA COUNTIES THROUGH 800 PM MDT...

At 726 PM MDT, Doppler radar was tracking a strong thunderstorm 24
miles south of Grand Junction, moving west at 30 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

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

This storm will remain over mainly rural areas of southwestern Delta
and south central Mesa Counties.

This includes the following highways...
 U.S. Highway 50 in Colorado between mile markers 48 and 66.
 Colorado 141 between mile markers 137 and 144.

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 3896 10820 3881 10802 3859 10853 3884 10863
TIME...MOT...LOC 0126Z 070DEG 63KT 3874 10858

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

LB
Local storm report, Jul 20, 7:45 PM MDT, 19 minutes before
Preliminary Local Storm Report
National Weather Service Grand Junction CO
745 PM MDT Mon Jul 20 2026

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

0735 PM     Debris Flow      3 SW New Castle         39.56N 107.57W
07/20/2026                   Garfield           CO   Dept of Highways

            Between Lyons Boulevard and Weare Lane (2
            miles east of the Silt area) from Mile Point
            100 to Mile Point 103.

&&

The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 6:03 PM MDTSpecial Weather StatementGJTSan Miguel27 min
Jul 20, 6:18 PM MDTSpecial Weather StatementGJTOuray27 min
Jul 20, 6:27 PM MDTSpecial Weather StatementGJTMesa33 min
Jul 20, 6:33 PM MDTSpecial Weather StatementGJTGarfield27 min
Jul 20, 6:59 PM MDTSpecial Weather StatementGJTMesa31 min
Jul 20, 7:02 PM MDTSpecial Weather StatementGJTDelta28 min
Jul 20, 7:14 PM MDTAreal Flood AdvisoryGJTDelta, Mesa26 min
Jul 20, 7:27 PM MDTSpecial Weather StatementGJTMesa33 min
Jul 20, 7:40 PM MDTFlash Flood Warning Considerable damage threatGJTDelta, Mesa3 hr
Jul 20, 8:04 PM MDTFlash Flood Warning Considerable damage threatGJTMesa3 hr
Jul 20, 8:09 PM MDTFlash Flood Warning Considerable damage threatGJTMesa3 hr
Jul 20, 8:27 PM MDTSpecial Weather StatementGJTMesa33 min
Jul 20, 8:45 PM MDTFlash Flood Warning Considerable damage threatGJTMontrose3 hr
Jul 20, 9:01 PM MDTFlash Flood Warning Considerable damage threatGJTMesa3 hr
Jul 20, 9:04 PM MDTAreal Flood AdvisoryGJTMesa3 hr
Jul 20, 9:08 PM MDTFlash Flood Warning Considerable damage threatGJTMesa3 hr
Jul 20, 9:24 PM MDTSpecial Weather StatementGJTMontezuma36 min
Jul 20, 10:06 PM MDTSpecial Weather StatementGJTMontezuma24 min
Jul 20, 10:41 PM MDTSpecial Weather StatementGJTMontezuma34 min
Jul 21, 9:59 AM MDTFlood WatchGJTDelta, Dolores, Garfield, Mesa, Montezuma, Montrose and 3 more11 hr
Jul 21, 3:19 PM MDTFlash Flood Warning Considerable damage threatGJTMontrose, San Miguel4 hr
Jul 21, 3:43 PM MDTSpecial Weather StatementGJTMontezuma32 min
Jul 21, 3:47 PM MDTFlash Flood Warning Considerable damage threatGJTDolores, Montezuma, San Miguel4 hr
Jul 21, 3:54 PM MDTSevere Thunderstorm WarningGJTMontezuma36 min
Jul 21, 3:58 PM MDTFlash Flood Warning Considerable damage threatGJTMontezuma3 hr
Jul 21, 4:12 PM MDTSevere Thunderstorm WarningGJTDolores, Montezuma48 min
Jul 21, 4:22 PM MDTFlash Flood Warning Considerable damage threatGJTDolores, Montezuma3 hr
Jul 21, 4:44 PM MDTSevere Thunderstorm WarningGJTDolores, Montezuma31 min
Jul 21, 5:06 PM MDTFlash Flood Warning Considerable damage threatGJTDolores, Montezuma3 hr
Jul 21, 5:11 PM MDTSpecial Weather StatementGJT19 min
Jul 21, 5:29 PM MDTSpecial Weather StatementGJT31 min
Jul 21, 5:34 PM MDTFlash Flood Warning Considerable damage threatGJTGarfield3 hr
Jul 21, 5:34 PM MDTSpecial Weather StatementGJT26 min
Jul 21, 5:40 PM MDTAreal Flood AdvisoryGJTOuray3 hr
Jul 21, 5:55 PM MDTAreal Flood AdvisoryGJTGarfield3 hr

Nearby

Flash Flood Warnings in Colorado, 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.