Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 18, NWS Salt Lake City, UT

July 19, 2021Kane County, Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 19, 2021, 1:44 PM MDT for Kane County, Washington County, Utah. It was in force for 5 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, 1:44 PM MDT (19:44 UTC)
Expired
Jul 19, 2021, 6:15 PM MDT
In force
5 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Kane County, UT, Washington County, UT

The radar

The Cedar City radar (KICX), 45 km from the middle of the area, began a volume at 19:44 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 12:00Z, 7.7 hours before the alert went out and 237 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-pSkew-T log-p diagram, Flgstf/Belemont, AZ at 12:00Z on 2021-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 96 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2021-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -2 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
96 J/kg
Mixed-layer CIN
-89 J/kg
Mixed-layer LCL
1290 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-2 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.

800 
WGUS55 KSLC 191944
FFWSLC
UTC025-053-192245-
/O.NEW.KSLC.FF.W.0018.210719T1944Z-210719T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  West Central Kane County in southern Utah...
  Eastern Washington County in southwestern Utah...

* Until 445 PM MDT.

* At 144 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.75 and 1.25 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...
  the East Fork of the Virgin River through Zion National Park to 
  the confluence of Shunes Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3719 11289 3719 11286 3718 11283 3718 11280
      3722 11279 3723 11275 3723 11274 3720 11272
      3717 11277 3717 11280 3717 11284 3718 11288
      3717 11290 3717 11292 3715 11296 3715 11299
      3716 11299 3718 11292

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

$$

SW
3 follow-up statements
935 
WGUS75 KSLC 192138
FFSSLC

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

UTC025-053-192245-
/O.CON.KSLC.FF.W.0018.000000T0000Z-210719T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-Washington UT-
338 PM MDT Mon Jul 19 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM MDT THIS 
AFTERNOON FOR WEST CENTRAL KANE AND EASTERN WASHINGTON COUNTIES...

At 338 PM MDT, the public reported flash flooding across the warned 
area. Between 0.75 and 1.25 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...
  the East Fork of the Virgin River through Zion National Park to 
  the confluence of Shunes Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3719 11289 3719 11286 3718 11283 3718 11280
      3722 11279 3723 11275 3723 11274 3720 11272
      3717 11277 3717 11280 3717 11284 3718 11288
      3717 11290 3717 11292 3715 11296 3715 11299
      3716 11299 3718 11292

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

$$

SW
071 
WGUS55 KSLC 192231
FFWSLC
UTC025-053-200015-
/O.EXT.KSLC.FF.W.0018.000000T0000Z-210720T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Salt Lake City has extended the

* Flash Flood Warning for...
  West Central Kane County in southern Utah...
  Eastern Washington County in southwestern Utah...

* Until 615 PM MDT.

* At 431 PM MDT, the public reported flash flooding across the 
  warned area. Between 1 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...
  the East Fork of the Virgin River through Zion National Park.

This includes the following streams and drainages...
  South Creek, Shunes Creek, Meadow Creek and East Fork Virgin River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3719 11289 3719 11286 3718 11283 3718 11280
      3722 11279 3723 11275 3723 11274 3720 11272
      3717 11277 3717 11280 3717 11284 3718 11288
      3717 11290 3717 11292 3715 11296 3715 11299
      3716 11299 3718 11292

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

$$

SW
569 
WGUS75 KSLC 200011
FFSSLC

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

UTC025-053-200021-
/O.EXP.KSLC.FF.W.0018.000000T0000Z-210720T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-Washington UT-
611 PM MDT Mon Jul 19 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 615 PM MDT THIS EVENING FOR 
WEST CENTRAL KANE AND EASTERN WASHINGTON COUNTIES...

The heavy rain has ended. Flash flooding was reported through the 
East Fork of the Virgin River, but 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 3719 11289 3719 11286 3718 11283 3718 11280
      3722 11279 3723 11275 3723 11274 3720 11272
      3717 11277 3717 11280 3717 11284 3718 11288
      3717 11290 3717 11292 3715 11296 3715 11299
      3716 11299 3718 11292

$$

SW

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 18, 7:02 PM MDTSpecial Weather StatementSLCTooele43 min
Jul 18, 7:54 PM MDTSpecial Weather StatementSLCTooele51 min
Jul 19, 4:32 AM MDTFlash Flood WatchSLCBeaver, Carbon, Duchesne, Emery, Garfield, Iron and 12 more19 hr
Jul 19, 2:34 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington3 hr
Jul 19, 2:45 PM MDTAreal Flood AdvisorySLCIron3 hr
Jul 19, 2:53 PM MDTSpecial Weather StatementSLCIron52 min
Jul 19, 3:04 PM MDTFlash Flood Warning Considerable damage threatSLCIron3 hr
Jul 19, 3:22 PM MDTSevere Thunderstorm WarningSLCIron38 min
Jul 19, 3:46 PM MDTSpecial Weather StatementSLCUtah44 min
Jul 19, 4:54 PM MDTSpecial Weather StatementSLCDavis, Salt Lake36 min
Jul 19, 5:57 PM MDTFlash Flood Warning Considerable damage threatSLCIron, Washington3 hr

Nearby

Flash Flood Warnings in Utah, 2021Every 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.