Alert archive / Utah / Flash Flood Warnings in 2020

Flash Flood Warning 7, NWS Salt Lake City, UT

July 23, 2020Emery County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 23, 2020, 12:55 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
Jul 23, 2020, 12:55 PM MDT (18:55 UTC)
Expired
Jul 23, 2020, 3:45 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), 232 km from the middle of the area, began a volume at 18:56 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, 6.9 hours before the alert went out and 163 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 2020-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 67 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 2020-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 176 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
67 J/kg
Mixed-layer CIN
-331 J/kg
Mixed-layer LCL
2027 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
176 m²/s²
0-3 km storm-relative helicity
285 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

667 
WGUS55 KSLC 231855
FFWSLC
UTC015-232145-
/O.NEW.KSLC.FF.W.0007.200723T1855Z-200723T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
1255 PM MDT Thu Jul 23 2020

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 345 PM MDT.

* At 1255 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Trail Mountain. Between 0.5 and 1 inch of rain 
  has fallen. Flash flooding is ongoing or expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving  over State Route 31 and through Huntington 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 Trail
           Mountain Burn Scar.

  SOURCE...Doppler radar.

  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 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 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 3947 11118 3947 11121 3938 11120 3935 11111
      3939 11108 3940 11111 3947 11114 3947 11115

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...0.75-1.5 INCHES IN 1 HOUR 

$$

SW
2 follow-up statements
622 
WGUS75 KSLC 232038
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
238 PM MDT Thu Jul 23 2020

UTC015-232145-
/O.CON.KSLC.FF.W.0007.000000T0000Z-200723T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emery UT-
238 PM MDT Thu Jul 23 2020

...FLASH FLOOD WARNING FOR THE TRAIL MOUNTAIN BURN SCAR REMAINS IN 
EFFECT UNTIL 345 PM MDT THIS AFTERNOON FOR NORTHWESTERN EMERY 
COUNTY...

At 238 PM MDT, Doppler radar indicated thunderstorms produced heavy 
rain over the Trail Mountain. Between 0.5 and 1 inch of rain has 
fallen. Little additional rainfall expected at this time. Flash 
flooding is ongoing or expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through the over State Route 31 and through Huntington 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 Trail Mountain Burn
         Scar.

SOURCE...Doppler radar.

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 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 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 3947 11118 3947 11121 3938 11120 3935 11111
      3939 11108 3940 11111 3947 11114 3947 11115

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...0.75-1.5 INCHES IN 1 HOUR 

$$

Church
427 
WGUS75 KSLC 232138 RRA
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
338 PM MDT Thu Jul 23 2020

UTC015-232148-
/O.EXP.KSLC.FF.W.0007.000000T0000Z-200723T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Emery UT-
338 PM MDT Thu Jul 23 2020

...FLASH FLOOD WARNING FOR THE TRAIL MOUNTAIN BURN SCAR WILL EXPIRE 
AT 345 PM MDT THIS AFTERNOON FOR NORTHWESTERN 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.

LAT...LON 3947 11118 3947 11121 3938 11120 3935 11111
      3939 11108 3940 11111 3947 11114 3947 11115

$$

SW

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 22, 6:45 PM MDTSevere Thunderstorm WarningSLCGarfield, San Juan30 min
Jul 23, 10:56 AM MDTSpecial Weather StatementSLCSevier49 min
Jul 23, 12:07 PM MDTSpecial Weather StatementSLCWayne38 min
Jul 23, 12:25 PM MDTSpecial Weather StatementSLCPiute50 min
Jul 23, 12:26 PM MDTSpecial Weather StatementSLCSevier49 min
Jul 23, 12:33 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne3 hr
Jul 23, 12:51 PM MDTSpecial Weather StatementSLCWashington39 min
Jul 23, 1:10 PM MDTSpecial Weather StatementSLCSanpete50 min
Jul 23, 1:25 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington3 hr
Jul 23, 1:32 PM MDTSpecial Weather StatementSLC43 min
Jul 23, 1:45 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne3 hr
Jul 23, 1:49 PM MDTSpecial Weather StatementSLCWasatch41 min
Jul 23, 2:36 PM MDTSpecial Weather StatementSLCWashington24 min
Jul 23, 2:42 PM MDTFlash Flood Warning Considerable damage threatSLCUtah3 hr
Jul 23, 2:49 PM MDTFlash Flood Warning Considerable damage threatSLCEmery, Wayne3 hr
Jul 23, 2:50 PM MDTSpecial Weather StatementSLCKane40 min
Jul 23, 3:22 PM MDTSpecial Weather StatementSLCWeber23 min
Jul 23, 3:41 PM MDTSpecial Weather StatementSLC49 min
Jul 23, 3:45 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Kane, San Juan3 hr
Jul 23, 4:07 PM MDTSpecial Weather StatementSLC38 min
Jul 23, 5:19 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield3 hr

Nearby

Flash Flood Warnings in Utah, 2020Every flash flood warning in 2020

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.