Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 21, NWS Salt Lake City, UT

July 19, 2021Iron County, Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 19, 2021, 5:57 PM MDT for Iron County, 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 19, 2021, 5:57 PM MDT (23:57 UTC)
Expired: Jul 19, 2021, 9:00 PM MDT
In force: 3 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Iron County, UT, Washington County, UT

The radar

The Cedar City radar (KICX), 41 km from the middle of the area, began a volume at 23:56 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, 12.0 hours before the alert went out and 234 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: 127 J/kg
Mixed-layer CIN: -232 J/kg
Mixed-layer LCL: 1964 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 68 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

363 
WGUS55 KSLC 192357
FFWSLC
UTC021-053-200300-
/O.NEW.KSLC.FF.W.0021.210719T2357Z-210720T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
557 PM MDT Mon Jul 19 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  Southern Iron County in southern Utah...
  North Central Washington County in southwestern Utah...

* Until 900 PM MDT.

* At 557 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 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...
  Pinto Creek through New Harmony and Ash Creek through Ash Creek 
  Reservoir.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3753 11338 3756 11336 3758 11334 3758 11332
      3755 11330 3753 11332 3748 11330 3747 11329
      3743 11324 3742 11324 3742 11325 3745 11329
      3747 11332 3749 11337 3751 11339

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

$$

SW

2 follow-up statements

415 
WGUS75 KSLC 200131
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
731 PM MDT Mon Jul 19 2021

UTC021-053-200300-
/O.CON.KSLC.FF.W.0021.000000T0000Z-210720T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-Washington UT-
731 PM MDT Mon Jul 19 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING 
FOR SOUTHERN IRON AND NORTH CENTRAL WASHINGTON COUNTIES...

At 731 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2 and 3 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...
  Pinto Creek through New Harmony and Ash Creek through Ask Creek 
  Reservoir.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3753 11338 3756 11336 3758 11334 3758 11332
      3755 11330 3753 11332 3748 11330 3747 11329
      3743 11324 3742 11324 3742 11325 3745 11329
      3747 11332 3749 11337 3751 11339

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

$$

SW

628 
WGUS75 KSLC 200252
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
852 PM MDT Mon Jul 19 2021

UTC021-053-200302-
/O.EXP.KSLC.FF.W.0021.000000T0000Z-210720T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Iron UT-Washington UT-
852 PM MDT Mon Jul 19 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING FOR 
SOUTHERN IRON AND NORTH CENTRAL WASHINGTON COUNTIES...

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

A Flash Flood Watch remains in effect until 1200 AM MDT for portions 
of central Utah, southern Utah and southwest Utah.

LAT...LON 3753 11338 3756 11336 3758 11334 3758 11332
      3755 11330 3753 11332 3748 11330 3747 11329
      3743 11324 3742 11324 3742 11325 3745 11329
      3747 11332 3749 11337 3751 11339

$$

SW

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 7:02 PM MDT	Special Weather Statement	SLC	Tooele	43 min
Jul 18, 7:54 PM MDT	Special Weather Statement	SLC	Tooele	51 min
Jul 19, 4:32 AM MDT	Flash Flood Watch	SLC	Beaver, Carbon, Duchesne, Emery, Garfield, Iron and 12 more	19 hr
Jul 19, 1:44 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane, Washington	5 hr
Jul 19, 2:34 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Iron, Washington	3 hr
Jul 19, 2:45 PM MDT	Areal Flood Advisory	SLC	Iron	3 hr
Jul 19, 2:53 PM MDT	Special Weather Statement	SLC	Iron	52 min
Jul 19, 3:04 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Iron	3 hr
Jul 19, 3:22 PM MDT	Severe Thunderstorm Warning	SLC	Iron	38 min
Jul 19, 3:46 PM MDT	Special Weather Statement	SLC	Utah	44 min
Jul 19, 4:54 PM MDT	Special Weather Statement	SLC	Davis, Salt Lake	36 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.