Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 6, NWS Salt Lake City, UT

July 9, 2021Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 9, 2021, 3:53 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 9, 2021, 3:53 PM MDT (21:53 UTC)
Expired: Jul 9, 2021, 7:00 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), 39 km from the middle of the area, began a volume at 21:56 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, 9.9 hours before the alert went out and 242 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: 406 J/kg
Mixed-layer CIN: -280 J/kg
Mixed-layer LCL: 3535 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: 0 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

618 
WGUS55 KSLC 092153
FFWSLC
UTC053-100100-
/O.NEW.KSLC.FF.W.0006.210709T2153Z-210710T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
353 PM MDT Fri Jul 9 2021

The National Weather Service in Salt Lake City has issued a

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

* Until 700 PM MDT.

* At 353 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.25 and 0.5 inches of 
  rain have fallen. The expected rainfall rate is 0.5 to 1.5 inches 
  in 1 hour. 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...
  Zion National Park, Virgin, Springdale and Rockville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 3739 11309 3740 11291 3721 11290 3716 11301
      3716 11309 3720 11318 3726 11315 3730 11310

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...0.5-1.5 INCHES IN 1 HOUR

$$

Church

2 follow-up statements

932 
WGUS75 KSLC 092304
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
504 PM MDT Fri Jul 9 2021

UTC053-100100-
/O.CON.KSLC.FF.W.0006.000000T0000Z-210710T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-
504 PM MDT Fri Jul 9 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM MDT THIS EVENING 
FOR EAST CENTRAL WASHINGTON COUNTY...

At 504 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 0.5 and 1.25 inches of rain 
have fallen. Additional rainfall amounts up to 0.25 inches are 
possible in the warned area. 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...
  Zion National Park, Virgin, Springdale and Rockville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 3739 11309 3740 11291 3721 11290 3716 11301
      3716 11309 3720 11318 3726 11315 3730 11310

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

$$

Church

191 
WGUS75 KSLC 100051
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
651 PM MDT Fri Jul 9 2021

UTC053-100101-
/O.EXP.KSLC.FF.W.0006.000000T0000Z-210710T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington UT-
651 PM MDT Fri Jul 9 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 7 PM MDT THIS EVENING FOR EAST 
CENTRAL WASHINGTON COUNTY...

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

LAT...LON 3739 11309 3740 11291 3721 11290 3716 11301
      3716 11309 3720 11318 3726 11315 3730 11310

$$

Church

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 2:43 PM MDT	Heat Advisory	SLC	Duchesne	3 days

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.