Alert archive / Utah / Flash Flood Warnings in 2012

Flash Flood Warning 55, NWS Salt Lake City, UT

August 21, 2012Kane County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 21, 2012, 6:26 PM MDT for Kane County, Utah. It was in force for 8 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 21, 2012, 6:26 PM MDT (00:26 UTC)
Expired: Aug 22, 2012, 2:30 AM MDT
In force: 8 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Flood severity: None

County Kane County, UT

The radar

The Cedar City radar (KICX), 85 km from the middle of the area, began a volume at 00:27 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.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 0.4 hours before the alert went out and 229 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: 93 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 1376 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: -11 m²/s²
0-3 km storm-relative helicity: 52 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.8

Open this sounding in Storm Lab

The text

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

152 
WGUS55 KSLC 220026
FFWSLC
UTC025-220830-
/O.NEW.KSLC.FF.W.0055.120822T0026Z-120822T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
626 PM MDT TUE AUG 21 2012

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL KANE COUNTY IN UTAH...SPECIFICALLY THE PARIA RIVER 
  DRAINAGE

* UNTIL 230 AM MDT WEDNESDAY

* AT 619 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  HEAVY RAIN HAS FALLEN ACROSS THE UPPER PARIA RIVER DRAINAGE FROM A 
  SERIES OF SLOW MOVING THUNDERSTORMS. RADAR INDICATES RAINFALL IN 
  EXCESS OF 3 INCHES HAS OCCURRED OVER THE HEADWATERS OF THE PARIA 
  EAST OF BRYCE CANYON NATIONAL PARK...WITH ADDITIONAL HEAVY RAIN 
  HAVING FALLEN DOWNSTREAM.  

* EXCESS RUNOFF FROM THIS RAINFALL WILL RESULT IN FLASH FLOODING 
  ALONG THE PARIA RIVER...WHICH SHOULD PASS UNDER THE HIGHWAY 89 
  BRIDGE BETWEEN 10 PM AND MIDNIGHT TONIGHT. 

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 3732 11207 3754 11224 3754 11184 3725 11188
      3701 11185 3700 11188

$$

MPS

3 follow-up statements

152 
WGUS75 KSLC 220256
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
856 PM MDT TUE AUG 21 2012

UTC025-220830-
/O.CON.KSLC.FF.W.0055.000000T0000Z-120822T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
KANE UT-
856 PM MDT TUE AUG 21 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM MDT FOR THE 
PARIA RIVER DRAINAGE IN CENTRAL KANE COUNTY...

AT 850 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR ESTIMATED 1 
TO 3 INCHES OF RAIN HAD FALLEN LATE TUESDAY AFTERNOON ACROSS THE 
HEADWATERS OF THE PARIA RIVER DRAINAGE. THIS RAINFALL HAS 
ENDED...HOWEVER EXCESSIVE RUNOFF FROM THIS RAINFALL IS LIKELY MAKING 
ITS WAY DOWN THE PARIA RIVER...AND SHOULD PASS UNDER THE HIGHWAY 89 
BRIDGE SOMETIME BETWEEN 10 PM AND MIDNIGHT.  

PEOPLE ARE STRONGLY ENCOURAGED TO STAY AWAY FROM THE PARIA RIVER 
THIS EVENING AS THIS FLOOD MAKES ITS WAY DOWNSTREAM. 

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 3732 11207 3754 11224 3754 11184 3725 11188
      3701 11185 3700 11188

$$

MPS

637 
WGUS75 KSLC 220638
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1238 AM MDT WED AUG 22 2012

UTC025-220830-
/O.CON.KSLC.FF.W.0055.000000T0000Z-120822T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
KANE UT-
1238 AM MDT WED AUG 22 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM MDT FOR 
CENTRAL KANE COUNTY...SPECIFICALLY THE PARIA RIVER DRAINAGE

AT 1230 AM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR ESTIMATED 1 
TO 3 INCHES OF RAIN HAD FALLEN LATE TUESDAY AFTERNOON ACROSS THE 
HEADWATERS OF THE PARIA RIVER DRAINAGE. THIS RAINFALL HAS 
ENDED...BUT HAS CREATED A FLASH FLOOD IN THE DRAINAGE. AS OF 12 AM 
MDT THE PARIA RIVER STREAM GAUGE REPORTED A JUMP FROM 14 CUBIC FEET 
PER SECOND /CFS/ TO 2625 CFS IN ONE HOUR WHERE IT PASSES UNDER US 
HIGHWAY 89. INDICATIONS ARE THAT PEAK FLOWS HAVE NOT BEEN MET YET.

PEOPLE ARE STRONGLY ENCOURAGED TO STAY AWAY FROM THE PARIA RIVER 
TONIGHT UNTIL FLOWS RECEDE LATER THIS MORNING.

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 3732 11207 3754 11224 3754 11184 3725 11188
      3701 11185 3700 11188

$$

MERRILL

146 
WGUS75 KSLC 220827
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
227 AM MDT WED AUG 22 2012

UTC025-220831-
/O.EXP.KSLC.FF.W.0055.000000T0000Z-120822T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
KANE UT-
227 AM MDT WED AUG 22 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 230 AM MDT FOR CENTRAL KANE
COUNTY...SPECIFICALLY FOR THE PARIA RIVER DRAINAGE...

RUNOFF FROM EARLIER PRECIPITATION HAS DIMINISHED GREATLY AND RIVER 
AND STREAM LEVELS ARE IN THE PROCESS OF DECREASING. THUNDERSTORMS 
OVER THE UPPER DRAINAGE OF BOTH THE PARIA RIVER AND COTTONWOOD WASH 
HAVE PRODUCED AN ADDITIONAL .50 TO .75 INCHES OF RAINFALL OVER THE 
LAST HOUR...THUS THE PARIA RIVER MAY RISE AGAIN BETWEEN 5AM AND 8AM 
MDT THIS MORNING. THIS SAID...ADDITIONAL FLASH FLOODING IS NOT 
EXPECTED...RATHER HIGHER THAN NORMAL FLOWS INTO THE DAYLIGHT HOURS. 
THEREFORE...THE FLASH FLOOD WARNING HAS BEEN ALLOWED TO EXPIRE. 
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 3732 11207 3754 11224 3754 11184 3725 11188
      3701 11185 3700 11188

$$

MERRILL

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 22, 12:59 AM MDT	Areal Flood Advisory	SLC	Washington	3 hr
Aug 22, 5:20 PM MDT	Flash Flood Warning	SLC	Garfield, Kane	6 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.