Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 123, NWS Salt Lake City, UT

August 19, 2021Kane County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 19, 2021, 2:31 AM MDT for Kane 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: Aug 19, 2021, 2:31 AM MDT (08:31 UTC)
Expired: Aug 19, 2021, 5:30 AM MDT
In force: 3 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Kane County, UT

The radar

The Cedar City radar (KICX), 117 km from the middle of the area, began a volume at 08:32 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 00:00Z, 8.5 hours before the alert went out and 210 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: 605 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 745 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 109 m²/s²
0-3 km storm-relative helicity: 108 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.8

Open this sounding in Storm Lab

The text

As transmitted.

295 
WGUS55 KSLC 190831
FFWSLC
UTC025-191130-
/O.NEW.KSLC.FF.W.0123.210819T0831Z-210819T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Salt Lake City has issued a

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

* Until 530 AM MDT.

* At 231 AM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 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...
  Big Water.

This includes the following streams and drainages...
  Wahweap Creek and Coyote Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3718 11187 3725 11182 3729 11170 3706 11159
      3705 11155 3700 11145 3700 11152 3703 11163
      3709 11171 3710 11177

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

$$

LC

2 follow-up statements

634 
WGUS75 KSLC 190955
FFSSLC

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

UTC025-191130-
/O.CON.KSLC.FF.W.0123.000000T0000Z-210819T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-
355 AM MDT Thu Aug 19 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 AM MDT EARLY THIS 
MORNING FOR SOUTH CENTRAL KANE COUNTY...

At 355 AM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. 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...
  Big Water.

This includes the following streams and drainages...
  Wahweap Creek and Coyote Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3718 11187 3725 11182 3729 11170 3706 11159
      3705 11155 3700 11145 3700 11152 3703 11163
      3709 11171 3710 11177

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

$$

LC

643 
WGUS75 KSLC 191128
FFSSLC

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

UTC025-191138-
/O.EXP.KSLC.FF.W.0123.000000T0000Z-210819T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-
528 AM MDT Thu Aug 19 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 530 AM MDT EARLY THIS MORNING 
FOR SOUTH CENTRAL KANE COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose an 
immediate threat for Wahweap and Coyote Creeks. Runoff from earlier 
heavy rain will continue to gradually diminish through the early 
morning hours. 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 3718 11187 3725 11182 3729 11170 3706 11159
      3705 11155 3700 11145 3700 11152 3703 11163
      3709 11171 3710 11177

$$

LC

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 18, 7:43 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane	4 hr
Aug 18, 8:01 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield	3 hr
Aug 18, 8:46 PM MDT	Special Weather Statement	SLC	Iron	44 min
Aug 18, 9:39 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Iron, Washington	3 hr
Aug 18, 9:48 PM MDT	Areal Flood Advisory	SLC	Iron	5 min
Aug 18, 9:53 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Iron	3 hr
Aug 18, 10:07 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Iron	3 hr
Aug 18, 11:11 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane, Washington	5 hr
Aug 19, 1:43 AM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Wayne	3 hr
Aug 19, 2:03 AM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Kane, San Juan	6 hr
Aug 19, 3:50 AM MDT	Special Weather Statement	SLC		25 min
Aug 19, 9:39 AM MDT	Special Weather Statement	SLC	Kane	36 min
Aug 19, 10:16 AM MDT	River Flood Warning	SLC	Duchesne	4 hr
Aug 19, 10:54 AM MDT	Special Weather Statement	SLC	Juab	51 min
Aug 19, 11:15 AM MDT	Areal Flood Advisory	SLC	Millard	2 hr
Aug 19, 11:42 AM MDT	Special Weather Statement	SLC	Sanpete	48 min
Aug 19, 12:29 PM MDT	Special Weather Statement	SLC	Sanpete	46 min
Aug 19, 12:49 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Wayne	3 hr
Aug 19, 1:04 PM MDT	Special Weather Statement	SLC	Utah	56 min
Aug 19, 1:25 PM MDT	Special Weather Statement	SLC	Carbon	50 min
Aug 19, 2:12 PM MDT	Special Weather Statement	SLC	Carbon, Duchesne	63 min
Aug 19, 2:59 PM MDT	Special Weather Statement	SLC	Duchesne	61 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.