Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 133, NWS Salt Lake City, UT

September 11, 2021Garfield County, Wayne County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Sep 11, 2021, 8:15 PM MDT for Garfield County, Wayne 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: Sep 11, 2021, 8:15 PM MDT (02:15 UTC)
Expired: Sep 11, 2021, 11:15 PM 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), 166 km from the middle of the area, began a volume at 02:17 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

Grand Junction, CO (KGJT), launched 00:00Z, 2.3 hours before the alert went out and 252 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 207 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 3403 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -61 m²/s²
0-3 km storm-relative helicity: 22 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

608 
WGUS55 KSLC 120215
FFWSLC
UTC017-055-120515-
/O.NEW.KSLC.FF.W.0133.210912T0215Z-210912T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
815 PM MDT Sat Sep 11 2021

The National Weather Service in Salt Lake City has issued a

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

* Until 1115 PM MDT.

* At 815 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 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 normally dry
           washes, roads and low water crossings.

* Some locations that will experience flash flooding include...
  Capitol Reef National Park.

This warning includes Sheets Gulch, Sandy Creek and Red Canyon in 
Capitol Reef National Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Remain alert for flooding even in locations not receiving rain. Dry 
washes, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

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 3823 11103 3816 11100 3798 11097 3795 11118
      3803 11122 3812 11119

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

$$

CRK

2 follow-up statements

102 
WGUS75 KSLC 120344
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
944 PM MDT Sat Sep 11 2021

UTC017-055-120515-
/O.CON.KSLC.FF.W.0133.000000T0000Z-210912T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-Wayne UT-
944 PM MDT Sat Sep 11 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM MDT THIS 
EVENING FOR NORTH CENTRAL GARFIELD AND SOUTHWESTERN WAYNE COUNTIES...

At 944 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. 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 normally dry washes,
         roads and low water crossings.

Some locations that will experience flash flooding include...
  Capitol Reef National Park.

This warning includes Sheets Gulch, Sandy Creek and Red Canyon in 
Capitol Reef National Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Remain alert for flooding even in locations not receiving rain. Dry 
washes, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

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 3823 11103 3816 11100 3798 11097 3795 11118
      3803 11122 3812 11119

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

$$

CRK

114 
WGUS75 KSLC 120505
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
1105 PM MDT Sat Sep 11 2021

UTC017-055-120515-
/O.EXP.KSLC.FF.W.0133.000000T0000Z-210912T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-Wayne UT-
1105 PM MDT Sat Sep 11 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1115 PM MDT THIS EVENING FOR 
NORTH CENTRAL GARFIELD AND SOUTHWESTERN WAYNE COUNTIES...

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

LAT...LON 3823 11103 3816 11100 3798 11097 3795 11118
      3803 11122 3812 11119

$$

CRK

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 11, 6:19 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Emery, Garfield, Wayne	3 hr
Sep 11, 6:30 PM MDT	Special Weather Statement	SLC	Juab	45 min
Sep 11, 7:16 PM MDT	Special Weather Statement	SLC	Juab	44 min
Sep 11, 7:24 PM MDT	Special Weather Statement	SLC		51 min
Sep 11, 8:22 PM MDT	Special Weather Statement	SLC	Sanpete	38 min
Sep 11, 9:06 PM MDT	Special Weather Statement	SLC	Sanpete	39 min
Sep 12, 3:29 PM MDT	Special Weather Statement	SLC	Box Elder	46 min
Sep 12, 3:37 PM MDT	Severe Thunderstorm Warning	SLC	Box Elder	23 min
Sep 12, 3:54 PM MDT	Severe Thunderstorm Warning	SLC	Box Elder	51 min
Sep 12, 4:13 PM MDT	Special Weather Statement	SLC	Box Elder	47 min
Sep 12, 4:31 PM MDT	Severe Thunderstorm Warning	SLC	Box Elder	44 min
Sep 12, 4:42 PM MDT	Severe Thunderstorm Warning	SLC	Box Elder	24 min
Sep 12, 5:08 PM MDT	Severe Thunderstorm Warning	SLC	Box Elder	20 min
Sep 12, 5:14 PM MDT	Special Weather Statement	SLC		46 min
Sep 12, 5:54 PM MDT	Severe Thunderstorm Warning	SLC	Box Elder	51 min

Nearby

Flash Flood Warnings in Utah, 2021 Every 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.