Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 121, NWS Salt Lake City, UT

August 19, 2021Garfield County, Wayne County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 19, 2021, 1:43 AM MDT for Garfield County, Wayne County, Utah. It was in force for 3 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 19, 2021, 1:43 AM MDT (07:43 UTC)
Expired
Aug 19, 2021, 4:30 AM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Garfield County, UT, Wayne County, UT

The radar

The Cedar City radar (KICX), 162 km from the middle of the area, began a volume at 07:46 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.

What was reported inside it

TimeReportWhereRemark
Aug 19, 2:30 AM MDTFLASH FLOOD10 Sse Capitol Reef Np, UTCAPITOL REEF NATIONAL PARK ESTIMATED PLEASANT CREEK AND SHEETS GULCH HAD 6-8 FEET OF FLOODING OVERNIGHT, AND BURRO, COTTONWOOD, AND 5 MILE WASHES HAD 2 TO 4 FEET OF FLOODING. TIME ESTIMATED FROM RADAR.
Aug 19, 2:30 AM MDTFLASH FLOOD2 Sw Capitol Reef Np, UTCAPITOL REEF NATIONAL PARK REPORTED SCENIC DRIVE WAS CLOSED AT GRAND WASH DUE TO A LARGE AMOUNT OF MUD ACROSS THE ROAD MAKING IT IMPASSIBLE. EXACT TIME OF THE FLASH FLOOD NOT KNOW DUE TO EARLY MORNING HOURS, BUT ESTIMATED FROM RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Grand Junction, CO (KGJT), launched 00:00Z, 7.7 hours before the alert went out and 255 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, Grand Junction, CO 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, Grand Junction, CO at 00:00Z on 2021-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 251 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2217 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
251 m²/s²
0-3 km storm-relative helicity
315 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

905 
WGUS55 KSLC 190743
FFWSLC
UTC017-055-191030-
/O.NEW.KSLC.FF.W.0121.210819T0743Z-210819T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
143 AM MDT Thu Aug 19 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  North Central Garfield County in southern Utah...
  South Central Wayne County in southern Utah...

* Until 430 AM MDT.

* At 143 AM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain in and around Capitol Reef National Park. Between 0.25 
  and 0.5 inches of rain have fallen. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Sheets Gulch, Capitol Gorge, the Grand Wash, and Pleasant Creek in 
  Capitol Reef National Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 3824 11127 3829 11119 3829 11111 3815 11106
      3812 11104 3807 11108 3801 11123 3813 11130

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

$$

LC
2 follow-up statements
158 
WGUS75 KSLC 190916
FFSSLC

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

UTC017-055-191030-
/O.CON.KSLC.FF.W.0121.000000T0000Z-210819T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-Wayne UT-
316 AM MDT Thu Aug 19 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 AM MDT EARLY THIS 
MORNING FOR NORTH CENTRAL GARFIELD AND SOUTH CENTRAL WAYNE 
COUNTIES...

At 316 AM MDT, Doppler radar indicated thunderstorms producing heavy 
rain in and around Capitol Reef National Park. Between 0.5 and 0.75 
inches of rain have fallen. Flash flooding is ongoing or expected to 
begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Sheets Gulch, Capitol Gorge, the Grand Wash, and Pleasant Creek in 
  Capitol Reef National Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 3824 11127 3829 11119 3829 11111 3815 11106
      3812 11104 3807 11108 3801 11123 3813 11130

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

$$

LC
406 
WGUS75 KSLC 191028
FFSSLC

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

UTC017-055-191038-
/O.EXP.KSLC.FF.W.0121.000000T0000Z-210819T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-Wayne UT-
428 AM MDT Thu Aug 19 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 430 AM MDT EARLY THIS MORNING 
FOR NORTH CENTRAL GARFIELD AND SOUTH CENTRAL WAYNE COUNTIES...

The heavy rain has ended in and around Capitol Reef National Park. 
Flooding is no longer expected to pose an immediate threat. Please 
continue to heed any remaining road closures.

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

LAT...LON 3824 11127 3829 11119 3829 11111 3815 11106
      3812 11104 3807 11108 3801 11123 3813 11130

$$

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, 10:07 PM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Aug 18, 11:11 PM MDTFlash Flood Warning Considerable damage threatSLCKane, Washington5 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.