Alert archive / Colorado / Flash Flood Warnings in 2021

Flash Flood Warning 78, NWS Grand Junction, CO

August 3, 2021Eagle County, Garfield County, Pitkin County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Aug 3, 2021, 3:27 PM MDT for Eagle County, Garfield County, Pitkin 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 3, 2021, 3:27 PM MDT (21:27 UTC)
Expired
Aug 3, 2021, 5:30 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, Pitkin County, CO

The radar

The Grand Junction radar (KGJX), 107 km from the middle of the area, began a volume at 21:30 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, 9.5 hours before the alert went out and 128 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 2021-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 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 2021-08-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 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
5 J/kg
Mixed-layer CIN
-176 J/kg
Mixed-layer LCL
1792 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

279 
WGUS55 KGJT 032127
FFWGJT
COC037-045-097-032330-
/O.NEW.KGJT.FF.W.0078.210803T2127Z-210803T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
327 PM MDT Tue Aug 3 2021

The National Weather Service in Grand Junction has issued a

* Flash Flood Warning for...
  The Lake Christine Fire Burn Area in...
  Southwestern Eagle County in west central Colorado...
  Eastern Garfield County in west central Colorado...
  Northwestern Pitkin County in west central Colorado...

* Until 530 PM MDT.

* At 327 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Lake Christine Fire Burn Area. 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 the burn scar into El Jebel as well as across 
Fryingpan Road north of Basalt. Runoff and debris flows will also 
impact Cattle Creek. 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 Lake
           Christine Fire Burn Area.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Lake Christine Fire Burn Area.

* Some locations that will experience flash flooding include...
  Basalt, Emma and El Jebel.

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 Lake Christine 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 3941 10711 3948 10713 3948 10711 3949 10705
      3947 10698 3944 10697 3937 10701 3936 10701
      3936 10705 3937 10707 3937 10708 3940 10711

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

$$

15
1 follow-up statement
961 
WGUS75 KGJT 032326
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
526 PM MDT Tue Aug 3 2021

COC037-045-097-032336-
/O.EXP.KGJT.FF.W.0078.000000T0000Z-210803T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eagle CO-Garfield CO-Pitkin CO-
526 PM MDT Tue Aug 3 2021

...FLASH FLOOD WARNING FOR THE LAKE CHRISTINE FIRE BURN AREA WILL 
EXPIRE AT 530 PM MDT THIS AFTERNOON FOR SOUTHWESTERN EAGLE, EASTERN 
GARFIELD AND NORTHWESTERN PITKIN 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.

A Flash Flood Watch remains in effect until 1200 AM MDT Wednesday.

LAT...LON 3941 10711 3948 10713 3948 10711 3949 10705
      3947 10698 3944 10697 3937 10701 3936 10701
      3936 10705 3937 10707 3937 10708 3940 10711

$$

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, 8:27 PM MDTFlash Flood Warning Considerable damage threatGJTEagle, Garfield2 hr
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, 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.