Alert archive / Colorado / Flash Flood Warnings in 2021

Flash Flood Warning 4, NWS Grand Junction, CO

June 29, 2021Eagle County, Garfield County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Jun 29, 2021, 5:05 PM MDT for Eagle County, Garfield 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
Jun 29, 2021, 5:05 PM MDT (23:05 UTC)
Expired
Jun 29, 2021, 8:00 PM MDT
In force
3 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), 108 km from the middle of the area, began a volume at 23:07 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 12:00Z, 11.1 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 12:00Z on 2021-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 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 12:00Z on 2021-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 92 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
6 J/kg
Mixed-layer CIN
-165 J/kg
Mixed-layer LCL
2268 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
92 m²/s²
0-3 km storm-relative helicity
162 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

403 
WGUS55 KGJT 292305
FFWGJT
COC037-045-300200-
/O.NEW.KGJT.FF.W.0004.210629T2305Z-210630T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
505 PM MDT Tue Jun 29 2021

The National Weather Service in Grand Junction has issued a

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

* Until 800 PM MDT.

* At 505 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Grizzly Creek Burn Area. 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 area. 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 Grizzly
           Creek Burn Area.

  SOURCE...Radar.

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

* Some locations that will experience flash flooding include...
  Shoshone.

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 Grizzly Creek 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 3967 10719 3965 10718 3965 10714 3962 10713
      3961 10714 3959 10710 3957 10711 3958 10715
      3957 10715 3957 10716 3956 10714 3956 10718
      3955 10717 3954 10720 3957 10729 3962 10729
      3964 10720 3966 10721

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

$$

NL
1 follow-up statement
516 
WGUS75 KGJT 300156
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
756 PM MDT Tue Jun 29 2021

COC037-045-300206-
/O.EXP.KGJT.FF.W.0004.000000T0000Z-210630T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eagle CO-Garfield CO-
756 PM MDT Tue Jun 29 2021

...FLASH FLOOD WARNING FOR THE GRIZZLY CREEK BURN AREA WILL EXPIRE 
AT 8 PM MDT THIS EVENING FOR WESTERN EAGLE AND EAST CENTRAL GARFIELD 
COUNTIES...

The heavy rain has ended, however periods of light rain will 
continue into the evening. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3967 10719 3965 10718 3965 10714 3962 10713
      3961 10714 3959 10710 3957 10711 3958 10715
      3957 10715 3957 10716 3956 10714 3956 10718
      3955 10717 3954 10720 3957 10729 3962 10729
      3964 10720 3966 10721

$$

ERW

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 29, 11:22 AM MDTFlash Flood WatchGJTEagle, Garfield, Moffat, Pitkin, Rio Blanco, Routt9 hr

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.