Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 134, NWS Salt Lake City, UT

September 18, 2021Emery County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Sep 18, 2021, 2:43 PM MDT for Emery County, Utah. 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
Sep 18, 2021, 2:43 PM MDT (20:43 UTC)
Expired
Sep 18, 2021, 5:45 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Emery County, UT

The radar

The Salt Lake City radar (KMTX), 236 km from the middle of the area, began a volume at 20:47 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

Salt Lake City I, UT (KSLC), launched 12:00Z, 8.7 hours before the alert went out and 167 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, Salt Lake City I, UT at 12:00Z on 2021-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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, Salt Lake City I, UT at 12:00Z on 2021-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 144 square meters per square second.19395878Sfc1 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
2721 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
144 m²/s²
0-3 km storm-relative helicity
178 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

415 
WGUS55 KSLC 182043
FFWSLC
UTC015-182345-
/O.NEW.KSLC.FF.W.0134.210918T2043Z-210918T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
243 PM MDT Sat Sep 18 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  The Trail Mountain Burn Scar in...
  West Central Emery County in central Utah...

* Until 545 PM MDT.

* At 243 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Trail Mountain Burn Scar. Flash flooding is 
  ongoing or expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through Huntington Canyon. 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 Trail
           Mountain Burn Scar.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Trail Mountain Burn Scar.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A debris flow is expected to impact Huntington Creek, spring water 
supply infrastructure, and potentially the Crandall Canyon Monument. 
Additionally the water intakes for the Huntington Power Plant just 
upstream from Huntington, and the Huntington Cleveland Irrigation 
Company may be impacted.

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3947 11112 3939 11105 3935 11097 3932 11097
      3937 11120 3948 11123

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

$$

CRK
1 follow-up statement
414 
WGUS75 KSLC 182206
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
406 PM MDT Sat Sep 18 2021

UTC015-182345-
/O.CON.KSLC.FF.W.0134.000000T0000Z-210918T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emery UT-
406 PM MDT Sat Sep 18 2021

...FLASH FLOOD WARNING FOR THE TRAIL MOUNTAIN BURN SCAR REMAINS IN 
EFFECT UNTIL 545 PM MDT THIS AFTERNOON FOR WEST CENTRAL EMERY 
COUNTY...

At 406 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain over the Trail Mountain Burn Scar. Flash flooding is ongoing or 
expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through Huntington Canyon. 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 Trail Mountain Burn
         Scar.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of areas in and around
         the Trail Mountain Burn Scar.

Some locations that will experience flash flooding include...
  Huntington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A debris flow is expected to impact Huntington Creek, spring water 
supply infrastructure, and potentially the Crandall Canyon Monument. 
Additionally the water intakes for the Huntington Power Plant just 
upstream from Huntington, and the Huntington Cleveland Irrigation 
Company may be impacted.

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3947 11112 3939 11105 3935 11097 3932 11097
      3937 11120 3948 11123

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

$$

CRK

The office that day

Everything else NWS Salt Lake City, UT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 18, 11:25 AM MDTSpecial Weather StatementSLCIron50 min
Sep 18, 1:07 PM MDTSpecial Weather StatementSLCSanpete38 min
Sep 18, 1:51 PM MDTSpecial Weather StatementSLCUtah, Wasatch39 min
Sep 18, 3:12 PM MDTHigh Wind WatchSLCUtah12 hr
Sep 18, 3:15 PM MDTSpecial Weather StatementSLCDuchesne45 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.