Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 85, NWS Salt Lake City, UT

August 2, 2021Emery County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 2, 2021, 1:27 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
Aug 2, 2021, 1:27 PM MDT (19:27 UTC)
Expired
Aug 2, 2021, 4:30 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), 233 km from the middle of the area, began a volume at 19:28 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, 7.5 hours before the alert went out and 164 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 2021-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 114 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 2021-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 square meters per square second.193958Sfc1 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
114 J/kg
Mixed-layer CIN
-88 J/kg
Mixed-layer LCL
1150 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
-6 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

211 
WGUS55 KSLC 021927
FFWSLC
UTC015-022230-
/O.NEW.KSLC.FF.W.0085.210802T1927Z-210802T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
127 PM MDT Mon Aug 2 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 430 PM MDT.

* At 127 PM MDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain over the Trail Mountain Burn 
  Scar. Between 0.25 and 0.5 inches of rain have fallen. The 
  expected rainfall rate is 1 to 2 inches 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 Trail Mountain Burn Scar. 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 and automated gauges.

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

* Some locations that will experience flash flooding include...
  mainly rural areas of West Central Emery County

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.

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry washes is likely. The heavy rains 
will likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

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

&&

LAT...LON 3946 11123 3950 11116 3935 11100 3934 11112
      3938 11120

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

Church
2 follow-up statements
220 
WGUS75 KSLC 021954
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
154 PM MDT Mon Aug 2 2021

UTC015-022230-
/O.CON.KSLC.FF.W.0085.000000T0000Z-210802T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emery UT-
154 PM MDT Mon Aug 2 2021

...FLASH FLOOD WARNING FOR THE TRAIL MOUNTAIN BURN SCAR REMAINS IN 
EFFECT UNTIL 430 PM MDT THIS AFTERNOON FOR WEST CENTRAL EMERY 
COUNTY...

At 154 PM MDT, Utah Department of Transportation reported 
thunderstorms producing heavy rain over the Trail Mountain Burn Scar 
have caused flooding across State Route 31. Between 0.5 and 1 inch 
of rain has fallen. The expected rainfall rate is 1 to 2 inches in 1 
hour. Flash flooding is occurring.

Excessive rainfall over the burn scar has resulted in debris flow 
moving through the Trail Mountain Burn Scar. 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...Department of Transportation reported.

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

Some locations that will experience flash flooding include...
  mainly rural areas of West Central Emery County

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.

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry washes is likely. The heavy rains 
will likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

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

&&

LAT...LON 3946 11123 3950 11116 3935 11100 3934 11112
      3938 11120

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

Church
055 
WGUS75 KSLC 022227
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
427 PM MDT Mon Aug 2 2021

UTC015-022237-
/O.EXP.KSLC.FF.W.0085.000000T0000Z-210802T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emery UT-
427 PM MDT Mon Aug 2 2021

...FLASH FLOOD WARNING FOR THE TRAIL MOUNTAIN BURN SCAR WILL EXPIRE 
AT 430 PM MDT THIS AFTERNOON FOR WEST CENTRAL EMERY COUNTY...

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, including SR-31 between mile markers 40 and 44 where 
UDOT continues to clean up debris across the road.

A Flash Flood Watch remains in effect until 900 PM MDT for portions 
of Utah and southwest Wyoming.

LAT...LON 3946 11123 3950 11116 3935 11100 3934 11112
      3938 11120

$$

Church

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 1, 6:01 PM MDTFlash Flood Warning Considerable damage threatSLCEmery, Garfield, Wayne3 hr
Aug 1, 6:09 PM MDTSevere Thunderstorm WarningSLCBox Elder, Tooele51 min
Aug 1, 6:17 PM MDTSpecial Weather StatementSLCBox Elder43 min
Aug 1, 6:27 PM MDTAreal Flood AdvisorySLCTooele3 hr
Aug 1, 6:36 PM MDTSpecial Weather StatementSLCSalt Lake39 min
Aug 1, 6:47 PM MDTSevere Thunderstorm WarningSLCDavis, Salt Lake, Tooele43 min
Aug 1, 7:00 PM MDTAreal Flood AdvisorySLCSalt Lake3 hr
Aug 1, 7:07 PM MDTAreal Flood AdvisorySLCGarfield, Iron113 min
Aug 1, 7:25 PM MDTSevere Thunderstorm WarningSLCDavis, Salt Lake35 min
Aug 1, 7:41 PM MDTAreal Flood AdvisorySLCSalt Lake3 hr
Aug 1, 7:58 PM MDTFlash Flood Warning Considerable damage threatSLCDavis3 hr
Aug 1, 8:25 PM MDTAreal Flood AdvisorySLCDavis3 hr
Aug 1, 8:51 PM MDTAreal Flood AdvisorySLCUtah114 min
Aug 1, 9:06 PM MDTAreal Flood AdvisorySLCDavis, Weber3 hr
Aug 2, 2:04 AM MDTFlash Flood WatchSLCBeaver, Box Elder, Cache, Carbon, Davis, Duchesne and 19 more18 hr
Aug 2, 1:16 PM MDTFlash Flood Warning Considerable damage threatSLCCarbon3 hr
Aug 2, 2:30 PM MDTFlash Flood Warning Considerable damage threatSLCWayne4 hr
Aug 2, 2:56 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne3 hr
Aug 2, 3:24 PM MDTSevere Thunderstorm WarningSLCGarfield66 min
Aug 2, 3:32 PM MDTSpecial Weather StatementSLCEmery43 min
Aug 2, 3:52 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield4 hr
Aug 2, 4:00 PM MDTSpecial Weather StatementSLCJuab45 min
Aug 2, 4:14 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, San Juan3 hr
Aug 2, 4:25 PM MDTSpecial Weather StatementSLC50 min
Aug 2, 4:55 PM MDTSpecial Weather StatementSLC50 min
Aug 2, 5:22 PM MDTSpecial Weather StatementSLCBox Elder38 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.