Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 90, NWS Salt Lake City, UT

August 12, 2021Kane County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 12, 2021, 4:25 PM MDT for Kane County, Utah. It was in force for 3 hr. 2 reports 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
Aug 12, 2021, 4:25 PM MDT (22:25 UTC)
Expired
Aug 12, 2021, 7:30 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Kane County, UT

The radar

The Cedar City radar (KICX), 66 km from the middle of the area, began a volume at 22:27 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.

What was reported inside it

TimeReportWhereRemark
Aug 12, 5:15 PM MDTFLASH FLOOD2 Wsw Kanab, UTPHOTOS OF WATER AND MUD OVER A ROADWAY IN KANAB AS WELL AS FLOODED BACKYARDS
Aug 12, 5:15 PM MDTFLASH FLOODKanab, UTPHOTOS OF WATER AND MUD OVER A ROADWAY IN KANAB AS WELL AS FLOODED BACKYARDS

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, 10.4 hours before the alert went out and 214 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 2021-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 40 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 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 53 square meters per square second.1939Sfc1 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
40 J/kg
Mixed-layer CIN
-119 J/kg
Mixed-layer LCL
1538 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
53 m²/s²
0-3 km storm-relative helicity
62 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

165 
WGUS55 KSLC 122225
FFWSLC
UTC025-130130-
/O.NEW.KSLC.FF.W.0090.210812T2225Z-210813T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
425 PM MDT Thu Aug 12 2021

The National Weather Service in Salt Lake City has issued a

* Flash Flood Warning for...
  Southwestern Kane County in southern Utah...

* Until 730 PM MDT.

* At 425 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 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
           and normally dry washes.

* Some locations that will experience flash flooding include...
  Kanab.

Additional locations include Johnson Wash and Kanab Creek. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Remain alert for flooding even in locations not receiving rain. Dry 
washes, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

&&

LAT...LON 3700 11260 3727 11258 3730 11224 3700 11234
      3700 11253 3700 11254 3700 11255

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

$$

AD
2 follow-up statements
741 
WGUS75 KSLC 130001
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
601 PM MDT Thu Aug 12 2021

UTC025-130130-
/O.CON.KSLC.FF.W.0090.000000T0000Z-210813T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-
601 PM MDT Thu Aug 12 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM MDT THIS 
EVENING FOR SOUTHWESTERN KANE COUNTY...

At 601 PM MDT, Flash Flooding has been reported near Kanab. Doppler 
radar indicates between 1 and 2 inches of rain have fallen. Flash 
flooding is already occurring.

HAZARD...Life threatening 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...
  Kanab, Johnson Wash and Kanab Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Remain alert for flooding even in locations not receiving rain. Dry 
washes, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

&&

LAT...LON 3700 11260 3727 11258 3730 11224 3700 11234
      3700 11253 3700 11254 3700 11255

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

$$

AD
596 
WGUS75 KSLC 130126
FFSSLC

Flash Flood Statement
National Weather Service Salt Lake City UT
726 PM MDT Thu Aug 12 2021

UTC025-130136-
/O.EXP.KSLC.FF.W.0090.000000T0000Z-210813T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-
726 PM MDT Thu Aug 12 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 730 PM MDT THIS EVENING FOR 
SOUTHWESTERN KANE COUNTY...

Heavy rainfall has ended across the area. 

LAT...LON 3700 11260 3727 11258 3730 11224 3700 11234
      3700 11253 3700 11254 3700 11255

$$

AD

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.