Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 32, NWS Grand Junction, CO

July 25, 2021Grand County, San Juan County, Utah

NWS Grand Junction, CO issued this flash flood warning at Jul 25, 2021, 3:30 PM MDT for Grand County, San Juan County, Utah. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 25, 2021, 3:30 PM MDT (21:30 UTC)
Expired
Jul 25, 2021, 6:30 PM MDT
In force
3 hr
Issued by
NWS Grand Junction, CO
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Grand County, UT, San Juan County, UT

The radar

The Grand Junction radar (KGJX), 115 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.

What was reported inside it

TimeReportWhereRemark
Jul 25, 4:13 PM MDTFLASH FLOOD6 Ese Grand Co Arpt, UTCORRECTS PREVIOUS FLASH FLOOD REPORT FROM 6 ESE GRAND CO ARPT. SIX FOOT WALL OF WATER, BOULDERS AND DEBRIS SWEPT OVER N. DESERT SOLITAIRE RD. FLOODING ORIGINATED FROM THE PACK CREEK BURN SCAR. NO INJURIES OR DEATHS REPORTED.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Grand Junction, CO (KGJT), launched 12:00Z, 9.5 hours before the alert went out and 101 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 2021-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2021-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2095 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
70 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

579 
WGUS55 KGJT 252130
FFWGJT
UTC019-037-260030-
/O.NEW.KGJT.FF.W.0032.210725T2130Z-210726T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
330 PM MDT Sun Jul 25 2021

The National Weather Service in Grand Junction has issued a

* Flash Flood Warning for...
  The Pack Creek Fire Burn Area in...
  Southeastern Grand County in east central Utah...
  Northeastern San Juan County in southeastern Utah...

* Until 630 PM MDT.

* At 330 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Pack Creek Fire Burn Area. Between 0.3 and 0.5 
  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 the Pack Creek 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 Pack Creek
           Fire Burn Area.

  SOURCE...Radar.

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

* Some locations that will experience flash flooding include...
  Spanish Valley.

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 Pack 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 3850 10927 3851 10926 3850 10922 3844 10923
      3844 10926 3845 10928 3842 10932 3843 10939
      3845 10939 3847 10934 3848 10930

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

$$

MMS
1 follow-up statement
958 
WGUS75 KGJT 260031
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
631 PM MDT Sun Jul 25 2021

UTC019-037-260041-
/O.EXP.KGJT.FF.W.0032.000000T0000Z-210726T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grand UT-San Juan UT-
631 PM MDT Sun Jul 25 2021

...FLASH FLOOD WARNING FOR THE PACK CREEK FIRE BURN AREA HAS EXPIRED 
FOR SOUTHEASTERN GRAND AND NORTHEASTERN SAN JUAN COUNTIES...

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

LAT...LON 3850 10927 3851 10926 3850 10922 3844 10923
      3844 10926 3845 10928 3842 10932 3843 10939
      3845 10939 3847 10934 3848 10930

$$

NL

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 25, 3:33 PM MDTAreal Flood AdvisoryGJTSan Juan117 min

Nearby

Flash Flood Warnings in Utah, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.