Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 3, NWS Salt Lake City, UT

June 29, 2021Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jun 29, 2021, 2:14 PM MDT for Washington County, Utah. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jun 29, 2021, 2:14 PM MDT (20:14 UTC)
Expired: Jun 29, 2021, 5:15 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), 64 km from the middle of the area, began a volume at 20:18 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.

What was reported inside it

Time	Report	Where	Remark
Jun 29, 3:31 PM MDT	FLASH FLOOD	Hildale, UT	FIRE DEPARTMENTS REPORTS MULTIPLE ROAD CLOSURES IN THE TOWN, MULTIPLE FLOODED RESIDENCES, AND SEVERAL STRANDED MOTORISTS DUE TO FLASH FLOODING IN THE AREA.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 8.2 hours before the alert went out and 226 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: 225 J/kg
Mixed-layer CIN: -162 J/kg
Mixed-layer LCL: 1570 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: -75 m²/s²
0-3 km storm-relative helicity: -28 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted.

353 
WGUS55 KSLC 292014
FFWSLC
UTC053-292315-
/O.NEW.KSLC.FF.W.0003.210629T2014Z-210629T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
214 PM MDT Tue Jun 29 2021

The National Weather Service in Salt Lake City has issued a

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

* Until 515 PM MDT.

* At 214 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain in Hildale. 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...
  Hildale.

This includes the following streams and drainages...
  Second Creek, Short Creek and South Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3700 11310 3709 11294 3707 11290 3705 11290
      3700 11293 3700 11299 3700 11300

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

$$

MT

2 follow-up statements

411 
WGUS75 KSLC 292142
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
342 PM MDT Tue Jun 29 2021

UTC053-292315-
/O.CON.KSLC.FF.W.0003.000000T0000Z-210629T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-
342 PM MDT Tue Jun 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 PM MDT THIS 
AFTERNOON FOR SOUTHEASTERN WASHINGTON COUNTY...

At 342 PM MDT, local law enforcement reported flash flooding from 
thunderstorms in the city of Hildale. The fire department reports 
multiple road closures in the city, multiple flooded residences, and 
several stranded motorists due to flash flooding in the area.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Law enforcement reported.

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

Some locations that will experience flash flooding include...
  Hildale.

This includes the following streams and drainages...
  Second Creek, Short Creek and South Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3700 11310 3709 11294 3707 11290 3705 11290
      3700 11293 3700 11299 3700 11300

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

$$

MT

777 
WGUS75 KSLC 292319
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
519 PM MDT Tue Jun 29 2021

UTC053-292329-
/O.EXP.KSLC.FF.W.0003.000000T0000Z-210629T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-
519 PM MDT Tue Jun 29 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHEASTERN WASHINGTON 
COUNTY...

Flood waters continue to recede. The heavy rain has ended. Flooding 
is no longer expected to pose a threat. Please continue to heed 
remaining road closures.

LAT...LON 3700 11310 3709 11294 3707 11290 3705 11290
      3700 11293 3700 11299 3700 11300

$$

GM

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 29, 1:53 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Garfield	3 hr
Jun 29, 2:11 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane, Washington	3 hr
Jun 29, 3:09 PM MDT	Special Weather Statement	SLC		36 min
Jun 29, 4:03 PM MDT	Severe Thunderstorm Warning	SLC	Kane, San Juan	27 min
Jun 29, 4:40 PM MDT	Flash Flood Warning Considerable damage threat	SLC	Kane	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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.