Alert archive / Colorado / Flash Flood Warnings in 2021

Flash Flood Warning 84, NWS Grand Junction, CO

September 28, 2021Garfield County, Mesa County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Sep 28, 2021, 4:03 PM MDT for Garfield County, Mesa County, Colorado. It was in force for 97 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 28, 2021, 4:03 PM MDT (22:03 UTC)
Expired: Sep 28, 2021, 5:40 PM MDT
In force: 97 min
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), 46 km from the middle of the area, began a volume at 22:02 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.

The nearest sounding before it

Grand Junction, CO (KGJT), launched 12:00Z, 10.1 hours before the alert went out and 30 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2319 m above ground
0-6 km bulk shear: 3 kt
0-1 km storm-relative helicity: -27 m²/s²
0-3 km storm-relative helicity: 112 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

546 
WGUS55 KGJT 282203
FFWGJT
COC045-077-290000-
/O.NEW.KGJT.FF.W.0084.210928T2203Z-210929T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
403 PM MDT Tue Sep 28 2021

The National Weather Service in Grand Junction has issued a

* Flash Flood Warning for...
  The Pine Gulch Fire Burn Area in...
  Southwestern Garfield County in west central Colorado...
  North Central Mesa County in west central Colorado...

* Until 600 PM MDT.

* At 403 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Pine Gulch Fire Burn Area. Up to 0.5 inches of 
  rain have fallen. The expected rainfall rate is 0.2 to 0.5 inches 
  in 30 minutes. Additional rainfall amounts of 0.5 to 1 inch are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Pine Gulch Burn 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 Pine Gulch
           Fire Burn Area.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Pine Gulch Fire Burn Area.

* Some locations that will experience flash flooding include...
  De Beque.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall will cause extensive and severe flash flooding of 
creeks...streams...and ditches in the Pine Gulch 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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3940 10870 3944 10876 3943 10878 3946 10879
      3951 10875 3953 10861 3951 10838 3949 10832
      3934 10820 3932 10823 3936 10828 3937 10835
      3937 10837 3936 10842 3932 10851 3929 10853
      3929 10858

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...0.2-0.5 INCHES IN 30 MINUTES

$$

Stearns

2 follow-up statements

533 
WGUS75 KGJT 282257
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
457 PM MDT Tue Sep 28 2021

COC045-077-290000-
/O.CON.KGJT.FF.W.0084.000000T0000Z-210929T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield CO-Mesa CO-
457 PM MDT Tue Sep 28 2021

...FLASH FLOOD WARNING FOR THE PINE GULCH FIRE BURN AREA REMAINS IN 
EFFECT UNTIL 6 PM MDT THIS EVENING FOR SOUTHWESTERN GARFIELD AND 
NORTH CENTRAL MESA COUNTIES...

At 457 PM MDT, Doppler radar indicated thunderstorms producing 
moderate to heavy rain over the Pine Gulch Fire Burn Area. Between 
0.5 and 1 inch of rain has fallen. Additional rainfall amounts up to 
0.25 inch are possible in the warned area. Flash flooding is ongoing 
or expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Pine Gulch Burn area. The debris flow can consist 
of rock, mud, vegetation and other loose materials.

HAZARD...Flash flooding caused by thunderstorms in and around the
         Pine Gulch Fire Burn Area.

SOURCE...Radar.

IMPACT...Flooding of areas in and around the Pine Gulch Fire Burn
         Area.

Some locations that will experience flash flooding include...
  De Beque.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall will cause extensive and severe flash flooding of 
creeks...streams...and ditches in the Pine Gulch 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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3940 10870 3944 10876 3943 10878 3946 10879
      3951 10875 3953 10861 3951 10838 3949 10832
      3934 10820 3932 10823 3936 10828 3937 10835
      3937 10837 3936 10842 3932 10851 3929 10853
      3929 10858

FLASH FLOOD...RADAR INDICATED

$$

Stearns

659 
WGUS75 KGJT 282340
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
540 PM MDT Tue Sep 28 2021

COC045-077-282350-
/O.CAN.KGJT.FF.W.0084.000000T0000Z-210929T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield CO-Mesa CO-
540 PM MDT Tue Sep 28 2021

...FLASH FLOOD WARNING FOR THE PINE GULCH FIRE BURN AREA IS 
CANCELLED FOR SOUTHWESTERN GARFIELD AND NORTH CENTRAL MESA 
COUNTIES...

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

LAT...LON 3940 10870 3944 10876 3943 10878 3946 10879
      3951 10875 3953 10861 3951 10838 3949 10832
      3934 10820 3932 10823 3936 10828 3937 10835
      3937 10837 3936 10842 3932 10851 3929 10853
      3929 10858

$$

Stearns

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 28, 4:26 AM MDT	Dense Fog Advisory	GJT	La Plata	3 hr
Sep 28, 12:06 PM MDT	Flash Flood Watch	GJT	Eagle, Garfield, Moffat, Pitkin, Rio Blanco, Routt	9 hr
Sep 28, 2:59 PM MDT	Areal Flood Advisory	GJT	Mesa	89 min
Sep 28, 3:05 PM MDT	Areal Flood Advisory	GJT	Rio Blanco	115 min
Sep 28, 5:44 PM MDT	Special Weather Statement	GJT	Mesa	31 min

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.