Alert archive / Utah / Flash Flood Warnings in 2012

Flash Flood Warning 43, NWS Salt Lake City, UT

August 10, 2012Emery County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 10, 2012, 12:29 PM MDT for Emery 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
Aug 10, 2012, 12:29 PM MDT (18:29 UTC)
Expired
Aug 10, 2012, 3:30 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Storm-based polygon
Flood severity
None

County Emery County, UT

The radar

The Salt Lake City radar (KMTX), 219 km from the middle of the area, began a volume at 18:32 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

Salt Lake City I, UT (KSLC), launched 12:00Z, 6.5 hours before the alert went out and 150 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, Salt Lake City I, UT at 12:00Z on 2012-08-10Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Salt Lake City I, UT at 12:00Z on 2012-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 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
3217 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
82 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.

162 
WGUS55 KSLC 101829
FFWSLC
UTC015-102130-
/O.NEW.KSLC.FF.W.0043.120810T1829Z-120810T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1229 PM MDT FRI AUG 10 2012

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN EMERY COUNTY IN UTAH...SPECIFICALLY THE SEELEY 
  BURN SCAR

* UNTIL 330 PM MDT

* AT 1223 PM MDT...DOPPLER RADAR INDICATED 0.25 TO 0.50 INCHES OF 
  RAIN HAS FALLEN ON THE SEELEY BURN SCAR IN THE PAST 30 MINUTES. 

* IT IS EXPECTED THAT THIS AMOUNT OF RAINFALL WILL RESULT IN FLASH   
  FLOODING AND A DEBRIS FLOW WHICH WILL IMPACT THE HUNTINGTON 
  POWER PLANT LOCATED JUST UPSTREAM OF THE TOWN OF HUNTINGTON. 
  DEBRIS AND ASH MAY ALSO IMPACT THE HUNTINGTON/CLEVELAND 
  IRRIGATION COMPANY. MUD AND WATER WILL ALSO LIKELY FLOW ACROSS 
  HIGHWAY 31 THROUGH HUNTINGTON CANYON. 

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 3949 11112 3949 11121 3960 11121 3961 11117
      3961 11115 3960 11114

$$

MPS
2 follow-up statements
155 
WGUS75 KSLC 102026
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
226 PM MDT FRI AUG 10 2012

UTC015-102130-
/O.CON.KSLC.FF.W.0043.000000T0000Z-120810T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
EMERY UT-
226 PM MDT FRI AUG 10 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 PM MDT FOR THE 
SEELEY BURN SCAR IN NORTHWESTERN EMERY COUNTY...

AT 221 PM MDT...DOPPLER RADAR INDICATED THAT 0.25 TO 0.50 INCHES HAS 
FALLEN ACROSS THE SEELEY BURN SCAR...WITH LOCALLY HIGHER TOTALS 
ALONG THE EASTERN EDGE. THIS AMOUNT OF RAINFALL IS SUFFICIENT TO 
CAUSE A DEBRIS FLOW FROM THE BURN SCAR...WHICH WILL LIKELY REACH 
HIGHWAY 31 BY 3 PM. ADDITIONALLY...THE HUNTINGTON POWER PLANT 
LOCATED JUST UPSTREAM OF THE TOWN OF HUNTINGTON AND THE 
HUNTINGTON/CLEVELAND IRRIGATION COMPANY WILL LIKELY BE IMPACTED. 

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 3949 11112 3949 11121 3960 11121 3961 11117
      3961 11115 3960 11114

$$

MPS
478 
WGUS75 KSLC 102127
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
327 PM MDT FRI AUG 10 2012

UTC015-102136-
/O.EXP.KSLC.FF.W.0043.000000T0000Z-120810T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
EMERY UT-
327 PM MDT FRI AUG 10 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 330 PM MDT FOR THE SEELEY 
BURN SCAR IN NORTHWESTERN EMERY COUNTY...

THE THREAT FOR FLASH FLOODING AND A DEBRIS FLOW FROM THE SEELEY BURN 
SCAR HAS ABATED. THEREFORE...THE FLASH FLOOD WARNING HAS BEEN 
ALLOWED TO EXPIRE. MONITOR NOAA WEATHER RADIO OR LOCAL TELEVISION OR 
RADIO FOR THE LATEST WEATHER INFORMATION.

IF A DEBRIS FLOW HAS OCCURRED IT IS IMPORTANT REALIZE THAT THE RUNOUT
AREA REMAINS VERY DANGEROUS. ADDITIONAL DEBRIS FLOWS MAY OCCUR WITHIN
MINUTES OF THE ORIGINAL FLOW. PLEASE REMAIN VIGILANT AND BE PREPARED
TO TAKE SWIFT ACTION.

LAT...LON 3949 11112 3949 11121 3960 11121 3961 11117
      3961 11115 3960 11114

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 12:40 PM MDTFlash Flood WarningSLCWayne3 hr
Aug 10, 1:25 PM MDTFlash Flood WarningSLCWayne3 hr
Aug 10, 4:17 PM MDTSpecial Weather StatementSLCEmery43 min
Aug 10, 4:45 PM MDTSpecial Weather StatementSLCTooele60 min
Aug 10, 5:51 PM MDTSpecial Weather StatementSLCDavis69 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.