Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 92, NWS Salt Lake City, UT

August 14, 2021Emery County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 14, 2021, 1:17 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 14, 2021, 1:17 PM MDT (19:17 UTC)
Expired
Aug 14, 2021, 4:15 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Flood severity
None

County Emery County, UT

The radar

The Salt Lake City radar (KMTX), 234 km from the middle of the area, began a volume at 19:18 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, 7.3 hours before the alert went out and 166 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 2021-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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 2021-08-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 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
4 J/kg
Mixed-layer CIN
-497 J/kg
Mixed-layer LCL
3291 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
28 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

411 
WGUS55 KSLC 141917
FFWSLC
UTC015-142215-
/O.NEW.KSLC.FF.W.0092.210814T1917Z-210814T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
117 PM MDT Sat Aug 14 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  The Trail Mountain burn scar in...
  Northwestern Emery County in central Utah...

* Until 415 PM MDT.

* At 117 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Trail Mountain Burn Scar. Between 0.25 and 0.5 
  inches of rain have fallen. 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 area. The debris flow 
can consist of rock, mud, vegetation and other loose materials.

  HAZARD...Flash flooding caused by thunderstorms in and around
           the Trail Mountain Burn Scar.

  SOURCE...Radar.

  IMPACT...Flooding of areas in and around the Trail Mountain
           Burn Scar.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry washes is likely. The heavy rains 
will likely trigger rock slides, 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 3939 11123 3939 11122 3936 11122 3939 11119
      3947 11121 3946 11115 3942 11116 3941 11112
      3938 11110 3936 11111 3938 11119 3935 11123

FLASH FLOOD...RADAR INDICATED

$$

AW
2 follow-up statements
127 
WGUS75 KSLC 142041
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
241 PM MDT Sat Aug 14 2021

UTC015-142215-
/O.CON.KSLC.FF.W.0092.000000T0000Z-210814T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emery UT-
241 PM MDT Sat Aug 14 2021

...FLASH FLOOD WARNING FOR THE TRAIL MOUNTAIN BURN SCAR REMAINS IN 
EFFECT UNTIL 415 PM MDT THIS AFTERNOON FOR NORTHWESTERN EMERY 
COUNTY...

At 241 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain over the Trail Mountain Burn Scar. Between 0.25 and 0.5 inches 
of rain have fallen. 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 area. The debris flow 
can consist of rock, mud, vegetation and other loose materials.

HAZARD...Flash flooding caused by thunderstorms in and around the
         Trail Mountain Burn Scar.

SOURCE...Radar.

IMPACT...Flooding of areas in and around the Trail Mountain Burn
         Scar.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry washes is likely. The heavy rains 
will likely trigger rock slides, 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 3939 11123 3939 11122 3936 11122 3939 11119
      3947 11121 3946 11115 3942 11116 3941 11112
      3938 11110 3936 11111 3938 11119 3935 11123

FLASH FLOOD...RADAR INDICATED

$$

AW
092 
WGUS75 KSLC 142216
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
416 PM MDT Sat Aug 14 2021

UTC015-142226-
/O.EXP.KSLC.FF.W.0092.000000T0000Z-210814T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emery UT-
416 PM MDT Sat Aug 14 2021

...FLASH FLOOD WARNING FOR THE TRAIL MOUNTAIN BURN SCAR HAS EXPIRED 
FOR NORTHWESTERN EMERY COUNTY...

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

LAT...LON 3939 11123 3939 11122 3936 11122 3939 11119
      3947 11121 3946 11115 3942 11116 3941 11112
      3938 11110 3936 11111 3938 11119 3935 11123

$$

AW

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 14, 3:19 PM MDTSpecial Weather StatementSLCIron41 min
Aug 14, 3:35 PM MDTSpecial Weather StatementSLC40 min
Aug 14, 4:47 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington3 hr
Aug 14, 5:14 PM MDTSpecial Weather StatementSLCWashington46 min
Aug 14, 5:25 PM MDTSevere Thunderstorm WarningSLCWashington36 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.