Alert archive / Colorado / Flash Flood Warnings in 2021

Flash Flood Warning 22, NWS Grand Junction, CO

July 23, 2021Eagle County, Garfield County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Jul 23, 2021, 5:34 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: Jul 23, 2021, 5:34 PM MDT (23:34 UTC)
Expired: Jul 23, 2021, 8:48 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), 107 km from the middle of the area, began a volume at 23:32 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, 11.6 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 21 J/kg
Mixed-layer CIN: -153 J/kg
Mixed-layer LCL: 1904 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: -41 m²/s²
0-3 km storm-relative helicity: -27 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

524 
WGUS55 KGJT 232334
FFWGJT
COC037-045-240300-
/O.NEW.KGJT.FF.W.0022.210723T2334Z-210724T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
534 PM MDT Fri Jul 23 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 900 PM MDT.

* At 534 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain moving toward the Grizzly Creek Fire Burn Area. Flash 
  flooding is 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 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...
  Glenwood Springs and 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 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.

&&

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

$$

as

1 follow-up statement

112 
WGUS75 KGJT 240248
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
848 PM MDT Fri Jul 23 2021

COC037-045-240258-
/O.CAN.KGJT.FF.W.0022.000000T0000Z-210724T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eagle CO-Garfield CO-
848 PM MDT Fri Jul 23 2021

...FLASH FLOOD WARNING FOR THE GRIZZLY CREEK FIRE BURN AREA IS 
CANCELLED FOR WESTERN EAGLE AND EAST CENTRAL GARFIELD COUNTIES...

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

A Flash Flood Watch remains in effect until 1200 AM MDT for portions 
of northwest 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

$$

JDC

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 23, 12:18 PM MDT	Special Weather Statement	GJT	Delta	27 min
Jul 23, 12:21 PM MDT	Special Weather Statement	GJT		39 min
Jul 23, 12:46 PM MDT	Areal Flood Advisory	GJT	Montezuma	3 hr
Jul 23, 12:48 PM MDT	Special Weather Statement	GJT	Montezuma	42 min
Jul 23, 1:22 PM MDT	Areal Flood Advisory	GJT	Dolores, Montezuma	3 hr
Jul 23, 1:58 PM MDT	Flash Flood Warning	GJT	Dolores, Montezuma	4 hr
Jul 23, 2:17 PM MDT	Areal Flood Advisory	GJT	Dolores, Montezuma, San Juan, San Miguel	3 hr
Jul 23, 3:07 PM MDT	Special Weather Statement	GJT	Chaffee	38 min
Jul 23, 3:26 PM MDT	Areal Flood Advisory	GJT	Ouray	3 hr
Jul 23, 3:42 PM MDT	Special Weather Statement	GJT	Chaffee	33 min
Jul 23, 3:50 PM MDT	Special Weather Statement	GJT	Archuleta	40 min
Jul 23, 3:50 PM MDT	Special Weather Statement	GJT	La Plata	25 min
Jul 23, 4:16 PM MDT	Special Weather Statement	GJT	Delta	29 min
Jul 23, 4:28 PM MDT	Areal Flood Advisory	GJT	Gunnison	3 hr
Jul 23, 4:57 PM MDT	Areal Flood Advisory	GJT	Hinsdale, Ouray, San Juan	3 hr
Jul 23, 5:11 PM MDT	Special Weather Statement	GJT	Mesa	49 min
Jul 23, 5:12 PM MDT	Areal Flood Advisory	GJT	Mesa	3 hr
Jul 23, 5:19 PM MDT	Areal Flood Advisory	GJT	Garfield	3 hr
Jul 23, 5:25 PM MDT	Areal Flood Advisory	GJT	Garfield, Mesa	3 hr
Jul 23, 5:29 PM MDT	Areal Flood Advisory	GJT	Garfield	3 hr
Jul 23, 5:36 PM MDT	Areal Flood Advisory	GJT	Gunnison, Hinsdale	3 hr
Jul 23, 5:39 PM MDT	Special Weather Statement	GJT	Hinsdale	51 min
Jul 23, 5:47 PM MDT	Special Weather Statement	GJT	Delta	43 min
Jul 23, 5:51 PM MDT	Areal Flood Advisory	GJT	Montrose	3 hr

Nearby

Flash Flood Warnings in Colorado, 2021 Every 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.