Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 119, NWS Salt Lake City, UT

August 18, 2021Iron County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 18, 2021, 10:07 PM MDT for Iron 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, 10:07 PM MDT (04:07 UTC)
Expired
Aug 19, 2021, 1:00 AM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Iron County, UT

The radar

The Cedar City radar (KICX), 23 km from the middle of the area, began a volume at 04:06 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

Las Vegas, NV (KVEF), launched 00:00Z, 4.1 hours before the alert went out and 289 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, Las Vegas, NV at 00:00Z on 2021-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Las Vegas, NV at 00:00Z on 2021-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3543 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
14 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

026 
WGUS55 KSLC 190407
FFWSLC
UTC021-190700-
/O.NEW.KSLC.FF.W.0119.210819T0407Z-210819T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
1007 PM MDT Wed Aug 18 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  The Brian Head Burn Scar in...
  East Central Iron County in southern Utah...

* Until 100 AM MDT.

* At 1007 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Brian Head Burn Scar. Between 0.5 and 1 inch 
  of rain has fallen. Additional rainfall amounts of 0.25 to 0.5 
  inches are possible in the warned area. Flash flooding is ongoing 
  or expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Brian Head 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 Brian Head
           Burn Scar.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Brian Head Burn Scar.

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

Flash flooding and debris flows are expected to impact state route 
143 between mile markers 6 and 10. Do not attempt to drive through 
any flooded roadways.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

It is expected that this amount of rainfall will result in flash 
flooding and a debris flow through the Parowan Creek drainage 
including Benson, Center, Bowery, and Soda Springs side drainages. 
State Route 143 is expected to receive debris, as well as locations 
along Parowan Creek downstream to the town of Parowan. People in 
this area should take action to ensure their safety!

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

&&

LAT...LON 3778 11270 3773 11274 3770 11279 3773 11285
      3777 11286 3780 11283 3782 11282 3783 11283
      3783 11290 3784 11289 3785 11282 3781 11280

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

$$

MPS
2 follow-up statements
607 
WGUS75 KSLC 190531
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
1131 PM MDT Wed Aug 18 2021

UTC021-190700-
/O.CON.KSLC.FF.W.0119.000000T0000Z-210819T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-
1131 PM MDT Wed Aug 18 2021

...FLASH FLOOD WARNING FOR THE BRIAN HEAD BURN SCAR REMAINS IN 
EFFECT UNTIL 1 AM MDT THURSDAY FOR EAST CENTRAL IRON COUNTY...

At 1131 PM MDT, Doppler radar indicated thunderstorms producing 
heavy rain over the Brian Head Burn Scar. Between 0.5 and 1 inch of 
rain has fallen.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Brian Head 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 Brian Head Burn Scar.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of areas in and around
         the Brian Head Burn Scar.

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

Flash flooding and debris flows are expected to impact state route 
143 between mile markers 6 and 10. Do not attempt to drive through 
any flooded roadways.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

It is expected that this amount of rainfall will result in flash 
flooding and a debris flow through the Parowan Creek drainage 
including Benson, Center, Bowery, and Soda Springs side drainages. 
State Route 143 is expected to receive debris, as well as locations 
along Parowan Creek downstream to the town of Parowan. People in 
this area should take action to ensure their safety!

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

&&

LAT...LON 3778 11270 3773 11274 3770 11279 3773 11285
      3777 11286 3780 11283 3782 11282 3783 11283
      3783 11290 3784 11289 3785 11282 3781 11280

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

$$

MPS
827 
WGUS75 KSLC 190659 RRA
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
1259 AM MDT Thu Aug 19 2021

UTC021-190709-
/O.EXP.KSLC.FF.W.0119.000000T0000Z-210819T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-
1259 AM MDT Thu Aug 19 2021

...FLASH FLOOD WARNING FOR THE BRIAN HEAD BURN SCAR WILL EXPIRE AT 1 
AM MDT EARLY THIS MORNING FOR EAST CENTRAL IRON COUNTY...

The heavy rain has ended over the Brian Head burn scar. Flooding is 
no longer expected to pose an immediate threat. Runoff and debris 
flows from earlier heavy rain will gradually diminish, although 
light to occasionally moderate rain will continue through late 
tonight. Please continue to heed any remaining road closures.

A Flash Flood Watch remains in effect until 600 AM MDT.

LAT...LON 3778 11270 3773 11274 3770 11279 3773 11285
      3777 11286 3780 11283 3782 11282 3783 11283
      3783 11290 3784 11289 3785 11282 3781 11280

$$

LC

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 7:43 PM MDTFlash Flood Warning Considerable damage threatSLCKane4 hr
Aug 18, 8:01 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield3 hr
Aug 18, 8:46 PM MDTSpecial Weather StatementSLCIron44 min
Aug 18, 9:39 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington3 hr
Aug 18, 9:48 PM MDTAreal Flood AdvisorySLCIron5 min
Aug 18, 9:53 PM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Aug 18, 11:11 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington5 hr
Aug 19, 1:43 AM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne3 hr
Aug 19, 2:03 AM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Kane, San Juan6 hr
Aug 19, 2:31 AM MDTFlash Flood Warning Considerable damage threatSLCKane3 hr
Aug 19, 3:50 AM MDTSpecial Weather StatementSLC25 min
Aug 19, 9:39 AM MDTSpecial Weather StatementSLCKane36 min
Aug 19, 10:16 AM MDTRiver Flood WarningSLCDuchesne4 hr
Aug 19, 10:54 AM MDTSpecial Weather StatementSLCJuab51 min
Aug 19, 11:15 AM MDTAreal Flood AdvisorySLCMillard2 hr
Aug 19, 11:42 AM MDTSpecial Weather StatementSLCSanpete48 min
Aug 19, 12:29 PM MDTSpecial Weather StatementSLCSanpete46 min
Aug 19, 12:49 PM MDTFlash Flood Warning Considerable damage threatSLCGarfield, Wayne3 hr
Aug 19, 1:04 PM MDTSpecial Weather StatementSLCUtah56 min
Aug 19, 1:25 PM MDTSpecial Weather StatementSLCCarbon50 min
Aug 19, 2:12 PM MDTSpecial Weather StatementSLCCarbon, Duchesne63 min
Aug 19, 2:59 PM MDTSpecial Weather StatementSLCDuchesne61 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.