Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 47, NWS Salt Lake City, UT

July 25, 2021Iron County, Kane County, Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 25, 2021, 4:52 PM MDT for Iron County, Kane County, Washington County, Utah. It was in force for 4 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: Jul 25, 2021, 4:52 PM MDT (22:52 UTC)
Expired: Jul 25, 2021, 8:45 PM MDT
In force: 4 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Iron County, UT, Kane County, UT, Washington County, UT

The radar

The Cedar City radar (KICX), 28 km from the middle of the area, began a volume at 22:53 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.

The nearest sounding before it

Las Vegas, NV (KVEF), launched 12:00Z, 10.9 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-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: 97 J/kg
Mixed-layer CIN: -248 J/kg
Mixed-layer LCL: 2117 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 69 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

051 
WGUS55 KSLC 252252
FFWSLC
UTC021-025-053-260245-
/O.NEW.KSLC.FF.W.0047.210725T2252Z-210726T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
452 PM MDT Sun Jul 25 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  South Central Iron County in southern Utah...
  Western Kane County in southern Utah...
  East Central Washington County in southwestern Utah...

* Until 845 PM MDT.

* At 452 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.75 and 2 inches of 
  rain have fallen over the headwaters of the North Fork of the 
  Virgin River, Crystal Creek, and Shiver Creek. 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...
  Zion National Park, Springdale and Rockville.

This includes the following streams and drainages...
  North Fork Virgin River, Deep Creek, Shiver Creek, and Crystal 
  Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3754 11307 3757 11299 3750 11285 3745 11272
      3741 11275 3739 11281 3737 11286 3732 11289
      3731 11292 3726 11293 3724 11295 3720 11297
      3715 11302 3716 11303 3723 11298 3726 11298
      3734 11300 3742 11304

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

$$

SW

2 follow-up statements

565 
WGUS75 KSLC 260145
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
745 PM MDT Sun Jul 25 2021

UTC021-025-053-260245-
/O.CON.KSLC.FF.W.0047.000000T0000Z-210726T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-Kane UT-Washington UT-
745 PM MDT Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM MDT THIS 
EVENING FOR SOUTH CENTRAL IRON, WESTERN KANE AND EAST CENTRAL 
WASHINGTON COUNTIES...

At 745 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 0.75 and 2 inches of rain have 
fallen over the headwaters of the North Fork of the Virgin River, 
Crystal Creek, and Shiver Creek. 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...
  Zion National Park, Springdale and Rockville.

This includes the following streams and drainages...
  North Fork Virgin River, Deep Creek, Shiver Creek, and Crystal 
  Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3754 11307 3757 11299 3750 11285 3745 11272
      3741 11275 3739 11281 3737 11286 3732 11289
      3731 11292 3726 11293 3724 11295 3720 11297
      3715 11302 3716 11303 3723 11298 3726 11298
      3734 11300 3742 11304

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

$$

SW

497 
WGUS75 KSLC 260240
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
840 PM MDT Sun Jul 25 2021

UTC021-025-053-260250-
/O.EXP.KSLC.FF.W.0047.000000T0000Z-210726T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-Kane UT-Washington UT-
840 PM MDT Sun Jul 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 845 PM MDT THIS EVENING FOR 
SOUTH CENTRAL IRON, WESTERN KANE AND EAST CENTRAL WASHINGTON 
COUNTIES...

The heavy rain has ended. Runoff from earlier heavy rainfall will 
continue to diminish through the evening hours. Flooding is no 
longer expected to pose a threat. Please continue to heed any road 
closures.

A Flash Flood Watch remains in effect until 1000 PM MDT for portions 
of southern Utah and southwest Utah.

LAT...LON 3754 11307 3757 11299 3750 11285 3745 11272
      3741 11275 3739 11281 3737 11286 3732 11289
      3731 11292 3726 11293 3724 11295 3720 11297
      3715 11302 3716 11303 3723 11298 3726 11298
      3734 11300 3742 11304

$$

SW

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 24, 7:17 PM MDT	Special Weather Statement	SLC	Garfield	28 min
Jul 24, 8:08 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Kane	3 hr
Jul 25, 2:25 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Iron	3 hr
Jul 25, 2:49 PM MDT	Special Weather Statement	SLC	Piute	26 min
Jul 25, 2:53 PM MDT	Special Weather Statement	SLC	Beaver	37 min
Jul 25, 3:11 PM MDT	Special Weather Statement	SLC	Piute	34 min
Jul 25, 3:18 PM MDT	Special Weather Statement	SLC	Sevier	27 min
Jul 25, 3:33 PM MDT	Special Weather Statement	SLC	Iron	27 min
Jul 25, 3:49 PM MDT	Severe Thunderstorm Warning	SLC	Iron	26 min
Jul 25, 4:11 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Iron	3 hr
Jul 25, 4:21 PM MDT	Special Weather Statement	SLC	Washington	24 min
Jul 25, 4:29 PM MDT	Areal Flood Advisory	SLC	Iron	3 hr
Jul 25, 4:41 PM MDT	Special Weather Statement	SLC	Washington	19 min
Jul 25, 4:41 PM MDT	Special Weather Statement	SLC	Iron	49 min
Jul 25, 5:16 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Washington	3 hr
Jul 25, 5:26 PM MDT	Severe Thunderstorm Warning	SLC	Washington	19 min
Jul 25, 5:42 PM MDT	Severe Thunderstorm Warning	SLC	Washington	33 min
Jul 25, 5:44 PM MDT	Special Weather Statement	SLC	Washington	31 min
Jul 25, 5:52 PM MDT	Special Weather Statement	SLC	Washington	23 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.