Alert archive / Colorado / Flash Flood Warnings in 2021

Flash Flood Warning 73, NWS Grand Junction, CO

August 2, 2021Eagle County, Garfield County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Aug 2, 2021, 8:27 PM MDT for Eagle County, Garfield County, Colorado. It was in force for 2 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 2, 2021, 8:27 PM MDT (02:27 UTC)
Expired
Aug 2, 2021, 10:30 PM MDT
In force
2 hr
Issued by
NWS Grand Junction, CO
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Eagle County, CO, Garfield County, CO

The radar

The Grand Junction radar (KGJX), 107 km from the middle of the area, began a volume at 02:29 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.

The nearest sounding before it

Grand Junction, CO (KGJT), launched 00:00Z, 2.5 hours before the alert went out and 125 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 2021-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 146 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 2021-08-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 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
146 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
2375 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
-1 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

360 
WGUS55 KGJT 030227
FFWGJT
COC037-045-030430-
/O.NEW.KGJT.FF.W.0073.210803T0227Z-210803T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
827 PM MDT Mon Aug 2 2021

The National Weather Service in Grand Junction has issued a

* Flash Flood Warning for...
  The Grizzly Creek Fire Burn Area in...
  Western Eagle County in west central Colorado...
  East Central Garfield County in west central Colorado...

* Until 1030 PM MDT.

* At 827 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the eastern part of the Grizzly Creek Fire Burn 
  Area in the Deadhorse Creek and French Creek basins Between 0.3 
  and 0.6 inches of rain have fallen. The expected rainfall rate is 
  0.5 to 1 inch in 1 hour. Flash flooding is ongoing or expected to 
  begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through Dead Horse and French Creek drainages. The debris 
flow can consist of rock, mud, vegetation and other loose materials.

  HAZARD...Thunderstorms producing flash flooding in and around
           the Grizzly Creek Fire Burn Area.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Grizzly Creek Fire Burn Area.

* Some locations that will experience flash flooding include...
  Deadhorse and French Creek Basins

This includes the following highways...
	Interstate 70 in Colorado between mile markers 125 and 129.

This includes the following streams and drainages...
 Deadhorse and French Creeks

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall will cause extensive and severe flash flooding of 
creeks...streams...and ditches in the Grizzly Creek Fire Burn Area. 
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.

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

&&

LAT...LON 3965 10722 3967 10720 3965 10713 3962 10712
      3961 10714 3960 10711 3958 10708 3957 10711
      3955 10714 3954 10720 3954 10724 3956 10731
      3963 10729 3963 10726 3964 10725

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...0.5-1 INCH IN 1 HOUR

$$

15
2 follow-up statements
869 
WGUS75 KGJT 030333
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
933 PM MDT Mon Aug 2 2021

COC037-045-030430-
/O.CON.KGJT.FF.W.0073.000000T0000Z-210803T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eagle CO-Garfield CO-
933 PM MDT Mon Aug 2 2021

...FLASH FLOOD WARNING FOR THE GRIZZLY CREEK FIRE BURN AREA REMAINS 
IN EFFECT UNTIL 1030 PM MDT THIS EVENING FOR WESTERN EAGLE AND EAST 
CENTRAL GARFIELD COUNTIES...

At 933 PM MDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain over the Grizzly Creek Fire Burn 
Area. Between 0.4 and 1 inch of rain has fallen. Flash flooding is 
ongoing or expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Glenwood Canyon near Dead Horse and French Creek 
drainages. The debris flow can consist of rock, mud, vegetation and 
other loose materials.

HAZARD...Thunderstorms producing flash flooding in and around the
         Grizzly Creek Fire Burn Area.

SOURCE...Radar and automated gauges.

IMPACT...Flash flooding of areas in and around the Grizzly Creek
         Fire Burn Area.

Some locations that will experience flash flooding include...
 Deadhorse and French Creek drainages.

This includes the following highways...
	Interstate 70 in Colorado between mile markers 118 and 129.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall will cause extensive and severe flash flooding of 
creeks...streams...and ditches in the Grizzly Creek Fire Burn Area. 
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.

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

&&

LAT...LON 3965 10722 3967 10720 3965 10713 3962 10712
      3961 10714 3960 10711 3958 10708 3957 10711
      3955 10714 3954 10720 3954 10724 3956 10731
      3963 10729 3963 10726 3964 10725

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

$$

15
202 
WGUS75 KGJT 030428
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
1028 PM MDT Mon Aug 2 2021

COC037-045-030438-
/O.EXP.KGJT.FF.W.0073.000000T0000Z-210803T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eagle CO-Garfield CO-
1028 PM MDT Mon Aug 2 2021

...FLASH FLOOD WARNING FOR THE GRIZZLY CREEK FIRE BURN AREA WILL 
EXPIRE AT 1030 PM MDT THIS EVENING FOR WESTERN EAGLE AND EAST 
CENTRAL GARFIELD COUNTIES...

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

A Flash Flood Watch remains in effect until 1200 AM MDT for portions 
of southwest Colorado and west central Colorado.



LAT...LON 3965 10722 3967 10720 3965 10713 3962 10712
      3961 10714 3960 10711 3958 10708 3957 10711
      3955 10714 3954 10720 3954 10724 3956 10731
      3963 10729 3963 10726 3964 10725

$$

15

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 2, 6:41 PM MDTSpecial Weather StatementGJT49 min
Aug 2, 7:44 PM MDTAreal Flood AdvisoryGJTGarfield, Mesa2 hr
Aug 2, 8:21 PM MDTAreal Flood AdvisoryGJTMesa114 min
Aug 2, 8:43 PM MDTFlash Flood Warning Considerable damage threatGJTGarfield, Mesa2 hr
Aug 3, 9:32 AM MDTAreal Flood AdvisoryGJTEagle3 hr
Aug 3, 12:16 PM MDTFlash Flood Warning Considerable damage threatGJTSan Miguel88 min
Aug 3, 2:54 PM MDTFlash Flood Warning Considerable damage threatGJTEagle, Garfield111 min
Aug 3, 3:21 PM MDTFlash Flood WarningGJTSan Miguel104 min
Aug 3, 3:27 PM MDTFlash Flood Warning Considerable damage threatGJTEagle, Garfield, Pitkin2 hr
Aug 3, 4:04 PM MDTSpecial Weather StatementGJTSan Miguel41 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.