Alert archive / Utah / Flash Flood Warnings in 2008

Flash Flood Warning 13, NWS Salt Lake City, UT

August 4, 2008Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 4, 2008, 4:39 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 4, 2008, 4:39 PM MDT (22:39 UTC)
Expired
Aug 4, 2008, 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), 31 km from the middle of the area, began a volume at 22:41 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 4, 5:50 PM MDTFLASH FLOOD6 Ne Virgin, UTFLASH FLOODING REPORTED ON NORTH CREEK DRAINAGE NEAR WESTERN BORDER OF ZION NATIONAL PARK BY PARK RANGERS. CREEK IS OUT OF ITS BANKS WITH TREES AND LOGS FLOWING DOWNSTREAM.

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 12:00Z, 10.7 hours before the alert went out and 269 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 12:00Z on 2008-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 25 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 12:00Z on 2008-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 square meters per square second.1939Sfc1 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
25 J/kg
Mixed-layer CIN
-173 J/kg
Mixed-layer LCL
1521 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
136 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.

000 
WGUS55 KSLC 042243
FFWSLC
UTC053-050145-
/O.NEW.KSLC.FF.W.0013.080804T2239Z-080805T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
439 PM MDT MON AUG 4 2008

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

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

* UNTIL 745 PM MDT

* AT 432 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  FLASH FLOODING FROM A THUNDERSTORM OVER THE WARNED AREA.

RADAR ESTIMATES OF OVER ONE AND A HALF INCHES OF RAIN HAS FALLEN IN 
THE WARNED AREA. THE HEAVIEST RAIN IS LOCATED IN THE NORTHWESTERN 
PORTIONS OF ZION NATIONAL PARK AS WELL AS AREAS JUST WEST OF THE 
PARK. AFFECTED DRAINAGES INCLUDE NORTH CREEK AND LA VERKIN CREEK.

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.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

LAT...LON 3748 11321 3748 11316 3746 11314 3746 11306
      3749 11304 3749 11300 3715 11303 3716 11325
TIME...MOT...LOC 2239Z 180DEG 0KT 3737 11310

$$

CHENG
3 follow-up statements
000 
WGUS75 KSLC 042326
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
517 PM MDT MON AUG 4 2008

UTC053-050145-
/O.CON.KSLC.FF.W.0013.000000T0000Z-080805T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
517 PM MDT MON AUG 4 2008

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

AT 511 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE FLASH FLOODING OVER THE WARNED AREA.

RADAR ESTIMATES OF OVER FOUR INCHES OF RAIN HAS FALLEN IN THE NORTH 
CREEK DRAINAGE...AND HEAVY RAIN CONTINUES AT THIS TIME. RUNOFF FROM 
THIS RAIN WILL RESULT IN SIGNIFICANT RISES TO NORTH CREEK WITHIN 
ZION NATIONAL PARK AS WELL AS IN AREAS TO THE WEST OF THE 
PARK...INCLUDING THE TOWN OF VIRGIN.

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.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

LAT...LON 3748 11321 3748 11316 3746 11314 3746 11306
      3749 11304 3749 11300 3715 11303 3716 11325
TIME...MOT...LOC 2317Z 180DEG 0KT 3737 11310

$$

CHENG
000 
WGUS75 KSLC 050021
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
608 PM MDT MON AUG 4 2008

UTC053-050145-
/O.CON.KSLC.FF.W.0013.000000T0000Z-080805T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
608 PM MDT MON AUG 4 2008

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

AT 602 PM MDT...FLASH FLOODING WAS REPORTED IN THE LEFT FORK OF 
NORTH CREEK WITHIN ZION NATIONAL PARK. CONSIDERABLE DEBRIS WAS 
REPORTED IN THE FLOODWATERS.

ALTHOUGH RAINFALL HAS DECREASED IN INTENSITY...RUNOFF FROM HEAVY 
RAIN EARLIER TODAY HAS RESULTED IN FLASH FLOODING ALONG NORTH CREEK. 
EXCESSIVE RUNOFF WILL CONTINUE THIS EVENING WITH WATER RUNNING DOWN 
NORTH CREEK TOWARDS THE TOWN OF VIRGIN.

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.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

LAT...LON 3748 11321 3748 11316 3746 11314 3746 11306
      3749 11304 3749 11300 3715 11303 3716 11325
TIME...MOT...LOC 0008Z 180DEG 0KT 3737 11310

$$

CHENG
000 
WGUS75 KSLC 050146
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
737 PM MDT MON AUG 4 2008

UTC053-050147-
/O.EXP.KSLC.FF.W.0013.000000T0000Z-080805T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
737 PM MDT MON AUG 4 2008

...THE FLASH FLOOD WARNING WILL EXPIRE AT 745 PM MDT FOR EAST CENTRAL
WASHINGTON COUNTY...

RAINFALL HAS DIMINISHED GREATLY OVER NORTH CREEK AND LA VERKIN CREEK 
THIS EVENING. THEREFORE...THE FLASH FLOOD WARNING HAS BEEN ALLOWED 
TO EXPIRE.

HOWEVER...THESE STREAMS WILL CONTINUE TO RUN HIGH AND CONTAIN A 
SIGNIFICANT AMOUNT OF DEBRIS FOR THE NEXT FEW HOURS FROM EARLIER 
FLASH FLOODING. THE VIRGIN RIVER MAY ALSO SEE SOME RISES AS 
FLOODWATERS FROM NORTH CREEK MAKE THEIR WAY INTO THE RIVER...BUT 
FLOODING IS NOT EXPECTED ALONG THE VIRGIN RIVER.
 
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 3748 11321 3748 11316 3746 11314 3746 11306
      3749 11304 3749 11300 3715 11303 3716 11325
TIME...MOT...LOC 0137Z 180DEG 0KT 3737 11310

$$

CHENG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 4, 2:11 PM MDTAreal Flood AdvisorySLCKane3 hr

Nearby

Flash Flood Warnings in Utah, 2008Every flash flood warning in 2008

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.