Alert archive / Utah / Flash Flood Warnings in 2012

Flash Flood Warning 47, NWS Salt Lake City, UT

August 17, 2012Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 17, 2012, 7:15 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
Aug 17, 2012, 7:15 PM MDT (01:15 UTC)
Expired
Aug 17, 2012, 10:10 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 01:16 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 17, 7:45 PM MDTFLASH FLOODHildale, UTSEVERAL REPORTS OF FLOODING IN HILDALE

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 00:00Z, 1.3 hours before the alert went out and 232 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 00:00Z on 2012-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 167 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 00:00Z on 2012-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -9 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
167 J/kg
Mixed-layer CIN
-75 J/kg
Mixed-layer LCL
1324 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
-31 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.

898 
WGUS55 KSLC 180115
FFWSLC
UTC053-180515-
/O.NEW.KSLC.FF.W.0047.120818T0115Z-120818T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
715 PM MDT FRI AUG 17 2012

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN WASHINGTON COUNTY IN UTAH...SPECIFICALLY IN AND       
  AROUND THE TOWN OF HILDALE

* UNTIL 1115 PM MDT

* AT 707 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  HEAVY RAIN FROM A THUNDERSTORM OVER THE WARNED AREA. DOPPLER RADAR 
  ESTIMATES OF 1.00 TO 1.50 INCHES OF RAIN HAS FALLEN IN AND NORTH   
  OF THE TOWN OF HILDALE. AN ADDITIONAL .50 TO .75 INCHES OF RAIN   
  CAN BE EXPECTED OVER THE NEXT 30 MINUTES. 

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.

&&

LAT...LON 3714 11302 3713 11291 3699 11292 3700 11307

$$

MERRILL
2 follow-up statements
304 
WGUS75 KSLC 180253
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
853 PM MDT FRI AUG 17 2012

UTC053-180515-
/O.CON.KSLC.FF.W.0047.000000T0000Z-120818T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
853 PM MDT FRI AUG 17 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM MDT FOR 
SOUTHEASTERN WASHINGTON COUNTY...SPECIFICALLY IN AND AROUND THE 
TOWN OF HILDALE...

AT 844 PM MDT...LOCAL LAW ENFORCEMENT REPORTED SEVERAL AREAS OF 
FLOODING IN THE THE TOWN OF HILDALE. DOPPLER RADAR ESTIMATES OF 1.50 
TO 2.0 INCHES OF WATER FELL OVER AN HOURS TIME WITHIN TOWN AND THE 
CANYON AREAS TO THE NORTH. THIS HEAVY RAINFALL HAS SUBSIDED BUT 
FLOWS ARE EXPECTED TO CONTINUE TO REMAIN ELEVATED ON SHORT CREEK 
THROUGH THIS EVENING.

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.

&&

LAT...LON 3714 11302 3713 11291 3699 11292 3700 11307

$$

MERRILL
357 
WGUS75 KSLC 180410
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1010 PM MDT FRI AUG 17 2012

UTC053-180421-
/O.CAN.KSLC.FF.W.0047.000000T0000Z-120818T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
1010 PM MDT FRI AUG 17 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR SOUTHEASTERN
WASHINGTON COUNTY...

RUNOFF FROM EARLIER PRECIPITATION HAS DIMINISHED GREATLY AND RIVER 
AND STREAM LEVELS HAVE DECREASED. THEREFORE...THE FLASH FLOOD 
WARNING HAS BEEN CANCELLED. MONITOR NOAA WEATHER RADIO OR LOCAL 
TELEVISION OR RADIO FOR THE LATEST WEATHER INFORMATION.

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.

LAT...LON 3714 11302 3713 11291 3699 11292 3700 11307

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 6:34 PM MDTFlash Flood WarningSLCWashington3 hr
Aug 18, 2:10 PM MDTRed Flag WarningSLCBeaver, Box Elder, Davis, Iron, Juab, Millard and 5 more34 hr

Nearby

Flash Flood Warnings in Utah, 2012Every flash flood warning in 2012

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.