Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 43, NWS Salt Lake City, UT

July 24, 2021Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 24, 2021, 5:24 PM MDT for Washington 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: Jul 24, 2021, 5:24 PM MDT (23:24 UTC)
Expired: Jul 24, 2021, 8:30 PM MDT
In force: 3 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Washington County, UT

The radar

The Cedar City radar (KICX), 77 km from the middle of the area, began a volume at 23:27 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, 11.4 hours before the alert went out and 197 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: 335 J/kg
Mixed-layer CIN: -191 J/kg
Mixed-layer LCL: 2063 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 121 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

165 
WGUS55 KSLC 242324
FFWSLC
UTC053-250230-
/O.NEW.KSLC.FF.W.0043.210724T2324Z-210725T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
524 PM MDT Sat Jul 24 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  Central Washington County in southwestern Utah...

* Until 830 PM MDT.

* At 524 PM MDT, the public reported flash flooding across the 
  warned area. Between 1.5 and 2 inches of rain have fallen. Flash 
  flooding is already occurring.

  HAZARD...Life threatening flash flooding. Heavy rain producing
           flash flooding.

  SOURCE...Public reported.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Gunlock State Park, Veyo and Gunlock.

This includes the following highways...
	Utah Route 18 near mile marker 20.

This includes the following streams and drainages...
  Santa Clara River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3733 11368 3732 11371 3731 11373 3729 11374
      3727 11377 3728 11377 3730 11375 3732 11374
      3733 11370 3735 11368 3738 11366 3742 11361
      3741 11356 3737 11354 3734 11356 3734 11361
      3734 11364

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

SW

2 follow-up statements

563 
WGUS75 KSLC 250114 RRA
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
714 PM MDT Sat Jul 24 2021

UTC053-250230-
/O.CON.KSLC.FF.W.0043.000000T0000Z-210725T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-
714 PM MDT Sat Jul 24 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM MDT THIS 
EVENING FOR CENTRAL WASHINGTON COUNTY...

At 714 PM MDT, the public reported flash flooding across the warned 
area. Between 1.5 and 2 inches of rain have fallen. Flash flooding 
is already occurring.

HAZARD...Life threatening flash flooding. Heavy rain producing
         flash flooding.

SOURCE...Public reported.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Gunlock State Park, Veyo and Gunlock.

This includes the following highways...
	Utah Route 18 near mile marker 20...and
	between mile markers 23 and 24.

This includes the following streams and drainages...
  Santa Clara River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3733 11368 3732 11371 3731 11373 3729 11374
      3727 11377 3728 11377 3730 11375 3732 11374
      3733 11370 3735 11368 3738 11366 3742 11361
      3741 11356 3737 11354 3734 11356 3734 11361
      3734 11364

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

SW

722 
WGUS75 KSLC 250227
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
827 PM MDT Sat Jul 24 2021

UTC053-250237-
/O.EXP.KSLC.FF.W.0043.000000T0000Z-210725T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-
827 PM MDT Sat Jul 24 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 830 PM MDT THIS EVENING FOR 
CENTRAL WASHINGTON COUNTY...

Flood waters have receded. The heavy rain has ended. 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 Sunday for 
portions of southern Utah and southwest Utah.

LAT...LON 3733 11368 3732 11371 3731 11373 3729 11374
      3727 11377 3728 11377 3730 11375 3732 11374
      3733 11370 3735 11368 3738 11366 3742 11361
      3741 11356 3737 11354 3734 11356 3734 11361
      3734 11364

$$

SW

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 23, 6:14 PM MDT	Areal Flood Advisory	SLC	Washington	61 min
Jul 24, 3:23 AM MDT	Flash Flood Watch	SLC	Beaver, Garfield, Iron, Kane, Piute, Washington and 1 more	42 hr
Jul 24, 12:56 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane	3 hr
Jul 24, 12:58 PM MDT	Special Weather Statement	SLC	Kane	32 min
Jul 24, 1:34 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield, Kane	4 hr
Jul 24, 2:13 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Washington	3 hr
Jul 24, 2:24 PM MDT	Severe Thunderstorm Warning	SLC	Washington	21 min
Jul 24, 3:16 PM MDT	Severe Thunderstorm Warning	SLC	Washington	29 min
Jul 24, 3:40 PM MDT	Severe Thunderstorm Warning	SLC	Iron, Washington	35 min
Jul 24, 4:04 PM MDT	Severe Thunderstorm Warning	SLC	Washington	26 min
Jul 24, 4:07 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane, Washington	3 hr
Jul 24, 4:12 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Iron, Washington	3 hr
Jul 24, 4:30 PM MDT	Severe Thunderstorm Warning	SLC	Washington	30 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.