Alert archive / Colorado / Flash Flood Warnings in 2021

Flash Flood Warning 70, NWS Grand Junction, CO

July 31, 2021Garfield County, Mesa County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Jul 31, 2021, 7:00 PM MDT for Garfield County, Mesa County, Colorado. It was in force for 2 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 31, 2021, 7:00 PM MDT (01:00 UTC)
Expired
Jul 31, 2021, 9:00 PM MDT
In force
2 hr
Issued by
NWS Grand Junction, CO
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Garfield County, CO, Mesa County, CO

The radar

The Grand Junction radar (KGJX), 45 km from the middle of the area, began a volume at 01:04 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.

What was reported inside it

TimeReportWhereRemark
Jul 31, 7:06 PM MDTFLASH FLOOD7 Ne Fruita, COFLASH FLOOD IN HUNTER CANYON 21 ROAD. ESTIMATED 8 FEET OF WATER MOVING DOWN WASH.
Jul 31, 7:10 PM MDTFLASH FLOOD10 Nne Loma, CO10 FT WALL OF WATER OUTSIDE OF WASH. EVACUATIONS IN ORDER FOR HOMES ALONG 16 ROAD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Grand Junction, CO (KGJT), launched 00:00Z, 1.0 hours before the alert went out and 22 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 2021-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 59 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 2021-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 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
59 J/kg
Mixed-layer CIN
-60 J/kg
Mixed-layer LCL
2545 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

196 
WGUS55 KGJT 010100
FFWGJT
COC045-077-010300-
/O.NEW.KGJT.FF.W.0070.210801T0100Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
700 PM MDT Sat Jul 31 2021

The National Weather Service in Grand Junction has issued a

* Flash Flood Warning for...
  Southwestern Garfield County in west central Colorado...
  Northwestern Mesa County in west central Colorado...

* Until 900 PM MDT.

* At 700 PM MDT, Emergency management reported flash flooding and a 
  wall of water exceeding washes along 21 Road and 16 Road. Flash 
  flooding is already occurring.

  HAZARD...Life threatening flash flooding.

  SOURCE...Emergency management reported.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, and roadways.

* Some locations that will experience flash flooding include...
  mainly rural areas of Southwestern Garfield and Northwestern Mesa 
  Counties along 21 Road and 16 Road Washes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Seek 
higher ground.

Be aware of your surroundings and do not drive on flooded roads.

Heed all evacuations. 

&&

LAT...LON 3939 10868 3939 10865 3937 10866 3936 10866
      3929 10858 3929 10853 3926 10852 3920 10857
      3918 10862 3920 10864 3920 10865 3920 10866
      3921 10866 3921 10867 3923 10867 3926 10872
      3927 10875 3929 10877 3933 10875 3936 10873

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

ERW
2 follow-up statements
337 
WGUS75 KGJT 010213
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
813 PM MDT Sat Jul 31 2021

COC045-077-010300-
/O.CON.KGJT.FF.W.0070.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield CO-Mesa CO-
813 PM MDT Sat Jul 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING 
FOR SOUTHWESTERN GARFIELD AND NORTHWESTERN MESA COUNTIES...

At 813 PM MDT, Emergency management reported flash flooding and a 
wall of water exceeding washes along 21 Road and 16 Road. Flash 
flooding continues.

HAZARD...Life threatening flash flooding.

SOURCE...Emergency management reported.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, and roadways.

Some locations that will experience flash flooding include...
  mainly rural areas of Southwestern Garfield and Northwestern Mesa 
  Counties along 21 Road and 16 Road Washes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain alert for flooding even in locations not receiving rain. 
Arroyos, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

Turn around, don't drown when encountering flooded roads. Seek 
higher ground.

Be aware of your surroundings and do not drive on flooded roads. 

Heed all evacuations. 

&&

LAT...LON 3939 10868 3939 10865 3937 10866 3936 10866
      3929 10858 3929 10853 3926 10852 3920 10857
      3918 10862 3920 10864 3920 10865 3920 10866
      3921 10866 3921 10867 3923 10867 3926 10872
      3927 10875 3929 10877 3933 10875 3936 10873

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

BWM
102 
WGUS75 KGJT 010305
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
905 PM MDT Sat Jul 31 2021

COC045-077-010315-
/O.EXP.KGJT.FF.W.0070.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield CO-Mesa CO-
905 PM MDT Sat Jul 31 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHWESTERN GARFIELD AND 
NORTHWESTERN MESA COUNTIES...

Flood waters are lowering, though washes and creeks from 16 Road to 
Kimball Creek will still have higher than normal flow for several 
more hours. Flooding is no longer expected to pose a threat. Please 
continue to heed remaining road closures and stay away from washes 
with fast flowing water.

LAT...LON 3939 10868 3939 10865 3937 10866 3936 10866
      3929 10858 3929 10853 3926 10852 3920 10857
      3918 10862 3920 10864 3920 10865 3920 10866
      3921 10866 3921 10867 3923 10867 3926 10872
      3927 10875 3929 10877 3933 10875 3936 10873

$$

BWM

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 6:11 PM MDTFlash Flood Warning Considerable damage threatGJTGarfield, Mesa109 min
Aug 1, 3:05 AM MDTFlash Flood WatchGJTArchuleta, Delta, Dolores, Eagle, Garfield, Gunnison and 12 more18 hr
Aug 1, 11:34 AM MDTSpecial Weather StatementGJTMesa26 min
Aug 1, 1:25 PM MDTFlash Flood WatchGJTArchuleta, Delta, Dolores, Eagle, Garfield, Gunnison and 12 more35 hr
Aug 1, 2:49 PM MDTAreal Flood AdvisoryGJTGarfield, Mesa3 hr
Aug 1, 3:20 PM MDTSpecial Weather StatementGJTGarfield40 min
Aug 1, 4:34 PM MDTAreal Flood AdvisoryGJTDelta, Mesa116 min

Nearby

Flash Flood Warnings in Colorado, 2021Every flash flood warning in 2021

Sources

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