Alert archive / Utah / Flash Flood Warnings in 2011

Flash Flood Warning 49, NWS Salt Lake City, UT

September 9, 2011Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Sep 9, 2011, 4:54 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
Sep 9, 2011, 4:54 PM MDT (22:54 UTC)
Expired
Sep 9, 2011, 7:45 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Flood severity
None

County Washington County, UT

The radar

The Cedar City radar (KICX), 58 km from the middle of the area, began a volume at 22:55 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, 10.9 hours before the alert went out and 221 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, Las Vegas, NV at 12:00Z on 2011-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Las Vegas, NV at 12:00Z on 2011-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3990 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
25 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

753 
WGUS55 KSLC 092254
FFWSLC
UTC053-100145-
/O.NEW.KSLC.FF.W.0049.110909T2254Z-110910T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
454 PM MDT FRI SEP 9 2011

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL WASHINGTON COUNTY IN UTAH

* UNTIL 745 PM MDT

* AT 442 PM MDT...DOPPLER RADAR INDICATED AND THE PUBLIC REPORTED    
  FLASH FLOODING FROM A THUNDERSTORM OVER THE WARNED AREA. THE UTAH  
  DEPARTMENT OF TRANSPORTATION REPORTS WATER AND DEBRIS ACROSS        
  HIGHWAY 9 EAST OF ROCKVILLE. HEAVY RAIN ALONG THE VIRGIN RIVER     
  BETWEEN ROCKVILLE AND VIRGIN WILL RESULT IN FLASH FLOODING         
  ALONG THE VIRGIN RIVER TO NEAR WASHINGTON.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LA VERKIN.
  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 3723 11331 3720 11305 3713 11308 3718 11324
      3718 11333 3713 11340 3715 11344

$$

CONGER
2 follow-up statements
973 
WGUS75 KSLC 100059
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
659 PM MDT FRI SEP 9 2011

UTC053-100145-
/O.CON.KSLC.FF.W.0049.000000T0000Z-110910T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
659 PM MDT FRI SEP 9 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM MDT FOR
CENTRAL WASHINGTON COUNTY...

AT 652 PM MDT...THE THUNDERSTORMS THAT PRODUCED EARLIER HEAVY RAIN 
HAVE DISSIPATED. FLASH FLOODING PRODUCED WATER AND DEBRIS ACROSS 
STATE HIGHWAY 9 BETWEEN ROCKVILLE AND VIRGIN EARLIER THIS EVENING. 
THE HEAVY RUNOFF WILL PRODUCE RAPID AND SIGNIFICANT RISES DOWNSTREAM 
ALONG THE VIRGIN RIVER TO NEAR THE TOWN OF WASHINGTON. FLASH 
FLOODING WILL REMAIN A THREAT ALONG LOW-LYING AREAS NEAR THE VIRGIN 
RIVER THROUGH 745 PM THIS EVENING. 


LAT...LON 3723 11331 3720 11305 3713 11308 3718 11324
      3718 11333 3713 11340 3715 11344

$$

CONGER
407 
WGUS75 KSLC 100147
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
747 PM MDT FRI SEP 9 2011

UTC053-100155-
/O.EXP.KSLC.FF.W.0049.000000T0000Z-110910T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
747 PM MDT FRI SEP 9 2011

...THE FLASH FLOOD WARNING HAS EXPIRED FOR CENTRAL WASHINGTON
COUNTY...

HEAVY RUNOFF FROM EARLIER PRECIPITATION WILL MAINTAIN ELEVATED FLOWS 
ALONG THE VIRGIN RIVER THIS EVENING. THE FLASH FLOODING WARNING HAS 
BEEN ALLOWED TO EXPIRE AS FLOODING IS NO LONGER ANTICIPATED FROM 
THIS HEAVY RAIN EVENT. MONITOR NOAA WEATHER RADIO OR LOCAL 
TELEVISION OR RADIO FOR THE LATEST WEATHER INFORMATION.

LAT...LON 3723 11331 3720 11305 3713 11308 3718 11324
      3718 11333 3713 11340 3715 11344

$$

CONGER

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 9, 4:16 PM MDTFlash Flood WarningSLCKane4 hr

Nearby

Flash Flood Warnings in Utah, 2011Every flash flood warning in 2011

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.