Alert archive / Utah / Flash Flood Warnings in 2012

Flash Flood Warning 41, NWS Salt Lake City, UT

August 1, 2012Carbon County, Emery County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 1, 2012, 5:27 PM MDT for Carbon County, Emery County, Utah. It was in force for 4 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 1, 2012, 5:27 PM MDT (23:27 UTC)
Expired: Aug 1, 2012, 9:30 PM MDT
In force: 4 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Flood severity: None

Counties Carbon County, UT, Emery County, UT

The radar

The Salt Lake City radar (KMTX), 226 km from the middle of the area, began a volume at 23:29 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

Time	Report	Where	Remark
Aug 1, 5:40 PM MDT	FLASH FLOOD	10 S Scofield Res, UT	DEBRIS FLOW FROM THE SEELEY BURN SCAR CROSSED HIGHWAY 31. A BRIDGE WAS LOST ON HIGHWAY 31.
Aug 1, 6:00 PM MDT	FLASH FLOOD	10 S Scofield Res, UT	LARGE DEBRIS FLOWS OCCURRED ON THE SEELEY BURN SCAR. HIGHWAY 31 WAS UNDERCUT IN A FEW PLACES BY HUNTINGTON CREEK AND DEBRIS OF UP TO 3 FEET SPANNED NEARLY A MILE. HIGHWAY 31 THROUGH HUNTINGTON CANYON IS EXPECTED TO BE CLOSED FOR SOME TIME AS IT IS IMPASSABLE.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Salt Lake City I, UT (KSLC), launched 12:00Z, 11.5 hours before the alert went out and 157 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 70 J/kg
Mixed-layer CIN: -410 J/kg
Mixed-layer LCL: 2205 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: -46 m²/s²
0-3 km storm-relative helicity: 79 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.

189 
WGUS55 KSLC 012327
FFWSLC
UTC007-015-020330-
/O.NEW.KSLC.FF.W.0041.120801T2327Z-120802T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
527 PM MDT WED AUG 1 2012

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHWESTERN CARBON COUNTY IN UTAH
  NORTHWESTERN EMERY COUNTY IN UTAH

* UNTIL 930 PM MDT

* AT 517 PM MDT...DOPPLER RADAR INDICATED THAT HEAVY RAINFALL HAS
  BEEN FALLING OVER THE SEELEY BURN SCAR. RADAR ESTIMATES INDICATE
  THAT OVER A HALF INCH OF RAINFALL HAS FALLEN ON THE SEELEY
  THE BURN SCAR OVER THE PAST HOUR.  
  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.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SOUTH
  HUGHES...ENGINEER....AND CORAL CANYONS AND HIGHWAY
  31 IN THE HUNTINGTON CREEK DRAINAGE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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 3952 11122 3954 11120 3959 11123 3966 11108
      3960 11105 3958 11105 3951 11110 3935 11095
      3932 11096 3936 11111 3950 11121

$$

LC

2 follow-up statements

715 
WGUS75 KSLC 020126
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
726 PM MDT WED AUG 1 2012

UTC007-015-020330-
/O.CON.KSLC.FF.W.0041.000000T0000Z-120802T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CARBON UT-EMERY UT-
726 PM MDT WED AUG 1 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 PM MDT FOR
NORTHWESTERN EMERY AND SOUTHWESTERN CARBON COUNTIES...

HEAVY RAINFALL OVER THE SEELEY BURN SCAR RESULTED IN DEBRIS FLOWS 
WHICH CROSSED HIGHWAY 31. HIGHWAY 31 IN HUNTINGTON CANYON IS CLOSED 
IN BOTH DIRECTIONS AND A BRIDGE HAS BEEN LOST.

ALTHOUGH PRECIPITATION HAS DECREASED...DEBRIS FLOWS FROM THE SEELEY 
BURN SCAR ARE EXPECTED TO CONTINUE TO AFFECT SOUTH 
HUGHES...ENGINEER...AND CORAL CANYONS AS WELL AS HUNTINGTON CANYON. 
THIS INCLUDES THE HUNTINGTON POWER PLANT LOCATED JUST UPSTREAM OF 
THE TOWN OF HUNTINGTON AS WELL AS THE HUNTINGTON/CLEVELAND 
IRRIGATION COMPANY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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 3952 11122 3954 11120 3959 11123 3966 11108
      3960 11105 3958 11105 3951 11110 3935 11095
      3932 11096 3936 11111 3950 11121

$$

LC

367 
WGUS75 KSLC 020327
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
927 PM MDT WED AUG 1 2012

UTC007-015-020331-
/O.EXP.KSLC.FF.W.0041.000000T0000Z-120802T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CARBON UT-EMERY UT-
927 PM MDT WED AUG 1 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 930 PM MDT FOR NORTHWESTERN
EMERY AND SOUTHWESTERN CARBON COUNTIES...

PRECIPITATION HAS TAPERED OFF OVER THE SEELEY BURN SCAR. 
THEREFORE...THE FLASH FLOOD WARNING HAS BEEN ALLOWED TO EXPIRE.

OVER 1.25 INCHES OF RAIN FROM EARLIER THUNDERSTORMS CAUSED 
SIGNIFICANT DEBRIS FLOWS ON THE SEELEY BURN SCAR. DEBRIS OF UP TO 3 
FEET COVERED HIGHWAY 31 FOR ALMOST A MILE IN HUNTINGTON CANYON. 
ALTHOUGH WATER LEVELS REMAIN HIGH ON HUNTINGTON CREEK...THE WATER 
WILL CONTINUE TO RECEDE THROUGH THE REST OF THE EVENING. MONITOR 
NOAA WEATHER RADIO OR LOCAL TELEVISION OR RADIO FOR THE LATEST 
WEATHER INFORMATION.

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.

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 3952 11122 3954 11120 3959 11123 3966 11108
      3960 11105 3958 11105 3951 11110 3935 11095
      3932 11096 3936 11111 3950 11121

$$

LC

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 6:30 PM MDT	Flash Flood Warning	SLC	Iron	4 hr
Jul 31, 6:30 PM MDT	Special Weather Statement	SLC	Kane	30 min
Jul 31, 10:51 PM MDT	Flash Flood Warning	SLC	Washington	4 hr
Aug 1, 2:30 AM MDT	Flash Flood Watch	SLC		20 hr
Aug 1, 2:51 PM MDT	Flash Flood Warning	SLC	Garfield	4 hr
Aug 1, 3:09 PM MDT	Flash Flood Warning	SLC	Garfield, Kane	6 hr
Aug 1, 4:05 PM MDT	Flash Flood Warning	SLC	Kane	4 hr
Aug 1, 5:17 PM MDT	Flash Flood Warning	SLC	Washington	4 hr
Aug 1, 5:23 PM MDT	Flash Flood Warning	SLC	Kane, Washington	4 hr

Nearby

Flash Flood Warnings in Utah, 2012 Every 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.