Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 112, NWS Salt Lake City, UT

August 18, 2021Utah County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 18, 2021, 3:25 PM MDT for Utah 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 18, 2021, 3:25 PM MDT (21:25 UTC)
Expired
Aug 18, 2021, 6:30 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Utah County, UT

The radar

The Salt Lake City radar (KMTX), 168 km from the middle of the area, began a volume at 21:26 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, 9.4 hours before the alert went out and 100 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 2021-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 7 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 2021-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 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
7 J/kg
Mixed-layer CIN
-398 J/kg
Mixed-layer LCL
1192 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

880 
WGUS55 KSLC 182125
FFWSLC
UTC049-190030-
/O.NEW.KSLC.FF.W.0112.210818T2125Z-210819T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
325 PM MDT Wed Aug 18 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  The Pole Creek portion of the Bald Mountain Burn Scar in...
  South Central Utah County in northern Utah...

* Until 630 PM MDT.

* At 325 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Pole Creek portion of the Bald 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 the Bald Mountain Burn Scar near Birdseye. 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 Pole Creek
           portion of the Bald Mountain Burn Scar.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Pole Creek portion of the Bald Mountain Burn Scar.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A debris flow is expected to impact US 89 near Birdseye between mile 
markers 306 and 311. People traveling through this area should be 
prepared for debris on the highway in both directions.

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

&&

LAT...LON 3994 11158 4000 11153 3998 11140 3990 11137
      3987 11153

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

$$

CRK
2 follow-up statements
591 
WGUS75 KSLC 182348
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
548 PM MDT Wed Aug 18 2021

UTC049-190030-
/O.CON.KSLC.FF.W.0112.000000T0000Z-210819T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Utah UT-
548 PM MDT Wed Aug 18 2021

...FLASH FLOOD WARNING FOR THE POLE CREEK PORTION OF THE BALD 
MOUNTAIN BURN SCAR REMAINS IN EFFECT UNTIL 630 PM MDT THIS EVENING 
FOR SOUTH CENTRAL UTAH COUNTY...

At 548 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain over the Pole Creek portion of the Bald 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 Pole Creek portion of the Bald 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 Pole Creek portion of
         the Bald Mountain Burn Scar.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of areas in and around
         the Pole Creek portion of the Bald Mountain Burn Scar.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A debris flow is expected to impact US 89 near Birdseye between mile 
markers 306 and 311. People traveling through this area should be 
prepared for debris on the highway in both directions.

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

&&

LAT...LON 3994 11158 4000 11153 3998 11140 3990 11137
      3987 11153

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

$$

Church
250 
WGUS75 KSLC 190020
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
620 PM MDT Wed Aug 18 2021

UTC049-190030-
/O.EXP.KSLC.FF.W.0112.000000T0000Z-210819T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Utah UT-
620 PM MDT Wed Aug 18 2021

...FLASH FLOOD WARNING FOR THE POLE CREEK PORTION OF THE BALD 
MOUNTAIN BURN SCAR WILL EXPIRE AT 630 PM MDT THIS EVENING FOR SOUTH 
CENTRAL UTAH COUNTY...

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

A Flash Flood Watch remains in effect until 600 AM MDT Thursday for 
portions of central Utah, northern Utah and southern Utah.

LAT...LON 3994 11158 4000 11153 3998 11140 3990 11137
      3987 11153

$$

Church

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 6:05 PM MDTFlash Flood Warning Considerable damage threatSLCMillard3 hr
Aug 17, 6:10 PM MDTSevere Thunderstorm WarningSLCJuab35 min
Aug 17, 6:31 PM MDTSevere Thunderstorm WarningSLCMillard59 min
Aug 17, 6:39 PM MDTSpecial Weather StatementSLCUtah36 min
Aug 17, 6:49 PM MDTSevere Thunderstorm WarningSLCUtah, Wasatch26 min
Aug 17, 6:57 PM MDTFlash Flood Warning Considerable damage threatSLCKane, San Juan5 hr
Aug 17, 7:14 PM MDTSevere Thunderstorm WarningSLCSummit, Wasatch31 min
Aug 17, 8:52 PM MDTSpecial Weather StatementSLCSalt Lake38 min
Aug 17, 9:30 PM MDTSpecial Weather StatementSLCTooele30 min
Aug 17, 9:55 PM MDTSpecial Weather StatementSLCKane35 min
Aug 17, 9:58 PM MDTSpecial Weather StatementSLCJuab32 min
Aug 17, 10:00 PM MDTSpecial Weather StatementSLCJuab30 min
Aug 17, 10:17 PM MDTSpecial Weather StatementSLCSalt Lake28 min
Aug 18, 12:23 AM MDTSpecial Weather StatementSLC52 min
Aug 18, 12:31 AM MDTSpecial Weather StatementSLCMillard44 min
Aug 18, 12:45 AM MDTSpecial Weather StatementSLCJuab45 min
Aug 18, 1:42 AM MDTSpecial Weather StatementSLCJuab48 min
Aug 18, 4:38 AM MDTFlash Flood Warning Considerable damage threatSLCIron5 hr
Aug 18, 4:41 AM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Aug 18, 6:02 AM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington4 hr
Aug 18, 7:30 AM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington90 min
Aug 18, 7:55 AM MDTAreal Flood WarningSLCGarfield, Iron, Kane, Washington6 hr
Aug 18, 8:58 AM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington92 min
Aug 18, 11:05 AM MDTSevere Thunderstorm WarningSLCTooele40 min
Aug 18, 11:45 AM MDTSpecial Weather StatementSLCSalt Lake45 min
Aug 18, 12:11 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne6 hr
Aug 18, 12:17 PM MDTAreal Flood AdvisorySLCDavis, Salt Lake, Tooele2 hr
Aug 18, 12:29 PM MDTSpecial Weather StatementSLC31 min
Aug 18, 12:34 PM MDTSevere Thunderstorm WarningSLCJuab, Tooele56 min
Aug 18, 12:47 PM MDTSpecial Weather StatementSLCPiute28 min
Aug 18, 1:05 PM MDTFlash Flood Warning Considerable damage threatSLCWayne3 hr
Aug 18, 1:12 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield2 hr
Aug 18, 1:14 PM MDTSpecial Weather StatementSLCBeaver31 min
Aug 18, 1:24 PM MDTAreal Flood WarningSLCJuab, Salt Lake, Tooele, Utah3 hr
Aug 18, 1:24 PM MDTSevere Thunderstorm WarningSLCJuab, Tooele, Utah81 min
Aug 18, 1:39 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington3 hr
Aug 18, 1:57 PM MDTAreal Flood AdvisorySLCSalt Lake, Utah2 hr
Aug 18, 2:27 PM MDTFlash Flood Warning Considerable damage threatSLCUtah3 hr
Aug 18, 2:37 PM MDTFlash Flood Warning Considerable damage threatSLCUtah113 min
Aug 18, 2:51 PM MDTSpecial Weather StatementSLCSummit24 min
Aug 18, 2:56 PM MDTSpecial Weather StatementSLCGarfield49 min
Aug 18, 3:14 PM MDTSpecial Weather StatementSLCKane46 min
Aug 18, 3:18 PM MDTSpecial Weather StatementSLCWasatch27 min
Aug 18, 3:41 PM MDTSpecial Weather StatementSLCSanpete49 min
Aug 18, 3:46 PM MDTFlash Flood Warning Considerable damage threatSLCEmery, Wayne3 hr
Aug 18, 4:16 PM MDTSpecial Weather StatementSLCKane44 min
Aug 18, 4:22 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield3 hr
Aug 18, 5:41 PM MDTSpecial Weather StatementSLC49 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.