Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 130, NWS Salt Lake City, UT

September 11, 2021Wayne County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Sep 11, 2021, 12:50 PM MDT for Wayne County, Utah. It was in force for 3 hr. 1 report 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: Sep 11, 2021, 12:50 PM MDT (18:50 UTC)
Expired: Sep 11, 2021, 4:00 PM MDT
In force: 3 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Wayne County, UT

The radar

The Cedar City radar (KICX), 164 km from the middle of the area, began a volume at 18:53 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

Time	Report	Where	Remark
Sep 11, 3:25 PM MDT	FLASH FLOOD	5 Sse Capitol Reef Np, UT	PARK RANGERS AND BROADCAST MEDIA REPORT FLASH FLOODING IN CAPITOL GORGE. ROAD TO THE TRAILHEAD IS WASHED OUT IN SEVERAL PLACES.

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 12:00Z, 6.8 hours before the alert went out and 253 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2996 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: 31 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

825 
WGUS55 KSLC 111850
FFWSLC
UTC055-112200-
/O.NEW.KSLC.FF.W.0130.210911T1850Z-210911T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
1250 PM MDT Sat Sep 11 2021

The National Weather Service in Salt Lake City has issued a

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

* Until 400 PM MDT.

* At 1250 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across Capitol Reef National Park, specifically along 
  the Scenic Drive, Capitol Gorge, and Grand Wash. 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...
  Capitol Reef National Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3828 11123 3830 11121 3830 11104 3820 11111
      3816 11121 3823 11127

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

$$

GM

2 follow-up statements

606 
WGUS75 KSLC 112043
FFSSLC

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

UTC055-112200-
/O.CON.KSLC.FF.W.0130.000000T0000Z-210911T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Wayne UT-
243 PM MDT Sat Sep 11 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 4 PM MDT THIS 
AFTERNOON FOR SOUTH CENTRAL WAYNE COUNTY...

At 243 PM MDT, Radar estimated rainfall from earlier thunderstorms 
ranged from .40-.60 inches in 30 minutes over portions of Capitol 
Reef National Park between Grand Wash and the Capitol Gorge 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 creeks and streams,
         urban areas, highways, streets and underpasses.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3828 11123 3830 11121 3830 11104 3820 11111
      3816 11121 3823 11127

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

$$

GM

249 
WGUS75 KSLC 112155
FFSSLC

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

UTC055-112205-
/O.EXP.KSLC.FF.W.0130.000000T0000Z-210911T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Wayne UT-
355 PM MDT Sat Sep 11 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 4 PM MDT THIS AFTERNOON FOR 
SOUTH CENTRAL WAYNE COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

LAT...LON 3828 11123 3830 11121 3830 11104 3820 11111
      3816 11121 3823 11127

$$

GM

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 10, 6:06 PM MDT	Severe Thunderstorm Warning	SLC	Box Elder, Weber	39 min
Sep 10, 6:20 PM MDT	Severe Thunderstorm Warning	SLC	Davis, Morgan, Weber	25 min
Sep 10, 6:42 PM MDT	Special Weather Statement	SLC	Morgan, Weber	33 min
Sep 10, 6:42 PM MDT	Special Weather Statement	SLC	Davis	33 min
Sep 10, 6:50 PM MDT	Severe Thunderstorm Warning	SLC	Davis, Salt Lake, Tooele	25 min
Sep 10, 7:10 PM MDT	Special Weather Statement	SLC	Salt Lake, Utah	50 min
Sep 10, 7:10 PM MDT	Severe Thunderstorm Warning	SLC	Davis, Morgan, Salt Lake, Weber	35 min
Sep 10, 7:16 PM MDT	Severe Thunderstorm Warning	SLC	Davis, Salt Lake	29 min
Sep 10, 7:24 PM MDT	Special Weather Statement	SLC	Rich	51 min
Sep 10, 7:24 PM MDT	Special Weather Statement	SLC	Cache	51 min
Sep 10, 7:38 PM MDT	Special Weather Statement	SLC	Cache, Morgan, Rich, Weber	52 min
Sep 11, 12:54 PM MDT	Special Weather Statement	SLC	Carbon	51 min
Sep 11, 1:39 PM MDT	Special Weather Statement	SLC	Duchesne	51 min
Sep 11, 1:40 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Carbon	3 hr
Sep 11, 3:17 PM MDT	Special Weather Statement	SLC	Duchesne	43 min
Sep 11, 4:25 PM MDT	Special Weather Statement	SLC	Millard	35 min
Sep 11, 5:10 PM MDT	Special Weather Statement	SLC	Juab	35 min
Sep 11, 5:19 PM MDT	Special Weather Statement	SLC	Millard	26 min
Sep 11, 5:44 PM MDT	Special Weather Statement	SLC	Millard	46 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.