Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 25, NWS Salt Lake City, UT

July 20, 2021Garfield County, Kane County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 20, 2021, 3:26 PM MDT for Garfield County, Kane County, Utah. It was in force for 6 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 20, 2021, 3:26 PM MDT (21:26 UTC)
Expired: Jul 20, 2021, 9:45 PM MDT
In force: 6 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Garfield County, UT, Kane County, UT

The radar

The Cedar City radar (KICX), 87 km from the middle of the area, began a volume at 21:25 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

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.4 hours before the alert went out and 231 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: 396 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 1392 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 5 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

776 
WGUS55 KSLC 202126
FFWSLC
UTC017-025-210345-
/O.NEW.KSLC.FF.W.0025.210720T2126Z-210721T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
326 PM MDT Tue Jul 20 2021

The National Weather Service in Salt Lake City has issued a

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

* Until 945 PM MDT Tuesday.

* At 326 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2 inches of 
  rain have fallen over the headwaters of the Paria River. Flash 
  flooding is ongoing or expected to begin shortly through the Paria 
  River to the Arizona border.

  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...
  mainly rural areas of Southwestern Garfield and Central Kane 
  Counties

This includes the following streams and drainages...
  Paria River, Hackberry Canyon, Hogeye Creek, Cottonwood Creek, 
  Snake Creek, Dry Valley Creek and Coyote Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3755 11194 3756 11191 3742 11183 3727 11188
      3723 11192 3714 11190 3702 11185 3700 11185
      3700 11187 3702 11187 3713 11193 3720 11194
      3732 11201 3736 11204 3737 11208 3741 11209
      3748 11202 3749 11199 3754 11196

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

$$

SW

2 follow-up statements

291 
WGUS75 KSLC 210045
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
645 PM MDT Tue Jul 20 2021

UTC017-025-210345-
/O.CON.KSLC.FF.W.0025.000000T0000Z-210721T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-Kane UT-
645 PM MDT Tue Jul 20 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 945 PM MDT THIS 
EVENING FOR SOUTHWESTERN GARFIELD AND CENTRAL KANE COUNTIES...

At 645 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1.5 and 2 inches of rain have 
fallen over the headwaters of the Paria River. Flash flooding is 
ongoing or expected to begin shortly through the Paria River to the 
Arizona border.

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...
  mainly rural areas of Southwestern Garfield and Central Kane 
  Counties

This includes the following streams and drainages...
  Paria River, Hackberry Canyon, Hogeye Creek, Cottonwood Creek, 
  Snake Creek, Dry Valley Creek and Coyote Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3755 11194 3756 11191 3742 11183 3727 11188
      3723 11192 3714 11190 3702 11185 3700 11185
      3700 11187 3702 11187 3713 11193 3720 11194
      3732 11201 3736 11204 3737 11208 3741 11209
      3748 11202 3749 11199 3754 11196

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

$$

SW

536 
WGUS75 KSLC 210342
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
942 PM MDT Tue Jul 20 2021

UTC017-025-210352-
/O.EXP.KSLC.FF.W.0025.000000T0000Z-210721T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Garfield UT-Kane UT-
942 PM MDT Tue Jul 20 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 945 PM MDT THIS EVENING FOR 
SOUTHWESTERN GARFIELD AND CENTRAL KANE COUNTIES...

The heavy rain has ended over the Paria River drainage. Flooding is 
no longer expected to pose a threat. However, runoff from earlier 
heavy rain over the headwaters of the Paria will continue to course 
through the river and gradually decrease through late this evening. 
Please continue to heed any road closures.

LAT...LON 3755 11194 3756 11191 3742 11183 3727 11188
      3723 11192 3714 11190 3702 11185 3700 11185
      3700 11187 3702 11187 3713 11193 3720 11194
      3732 11201 3736 11204 3737 11208 3741 11209
      3748 11202 3749 11199 3754 11196

$$

LC

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 6:01 PM MDT	Special Weather Statement	SLC	Tooele	59 min
Jul 19, 6:10 PM MDT	Special Weather Statement	SLC	Juab	65 min
Jul 19, 6:13 PM MDT	Special Weather Statement	SLC	Washington	47 min
Jul 19, 8:19 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane	86 min
Jul 20, 12:11 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Wayne	3 hr
Jul 20, 1:18 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Iron, Washington	4 hr
Jul 20, 2:21 PM MDT	Special Weather Statement	SLC	Iron	39 min
Jul 20, 3:41 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Kane	3 hr
Jul 20, 4:03 PM MDT	Special Weather Statement	SLC	Sevier	27 min
Jul 20, 4:58 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield	3 hr

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.