Alert archive / Utah / Flash Flood Warnings in 2007

Flash Flood Warning 5, NWS Salt Lake City, UT

July 24, 2007Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 24, 2007, 5:29 AM 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 counties it named, with what was reported inside it.

The facts

Issued
Jul 24, 2007, 5:29 AM MDT (11:29 UTC)
Expired
Jul 24, 2007, 8:30 AM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Whole counties

County Washington County, UT

The radar

The Cedar City radar (KICX), 66 km from the middle of the area, began a volume at 11:32 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.

What was reported inside it

TimeReportWhereRemark
Jul 24, 5:30 AM MDTFLASH FLOOD4 S St. George, UTFLASH FLOOD AFFECTING AREAS SOUTH OF ST. GEORGE. WATER, MUD, AND ROCKS ON THE ROADS IN BLOOMINGTON. RISE OF 500 CFS IN MAINSTEM VIRGIN RIVER.

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

The nearest sounding before it

Mercury/Desert R, NV (KDRA), launched 00:00Z, 11.5 hours before the alert went out and 234 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, Mercury/Desert R, NV at 00:00Z on 2007-07-24Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Mercury/Desert R, NV at 00:00Z on 2007-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 46 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3969 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
46 m²/s²
0-3 km storm-relative helicity
107 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 241131
FFWSLC
UTC053-241430-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
529 AM MDT TUE JUL 24 2007

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL WASHINGTON COUNTY IN UTAH...
  THIS INCLUDES THE CITY OF ST GEORGE...

* UNTIL 830 AM MDT

* AT 524 AM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  FLASH FLOODING FROM A THUNDERSTORM OVER THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED THE VIRGIN    
  RIVER SOUTHEAST OF WASHINGTON DOWNSTREAM TO SOUTH OF ST. GEORGE.

VERY HEAVY RAIN ALONG THE VIRGIN RIVER DRAINAGE SOUTHEAST OF WASHINGTON
WILL CAUSE A RAPID INCREASE IN THE FLOW THROUGH THE VIRGIN RIVER 
DOWNSTREAM TO ST. GEORGE. 

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

IN HILLY TERRAIN THERE ARE HUNDREDS OF LOW WATER CROSSINGS WHICH ARE
POTENTIALLY DANGEROUS IN HEAVY RAIN. DO NOT ATTEMPT TO TRAVEL ACROSS
FLOODED ROADS. FIND ALTERNATE ROUTES. IT TAKES ONLY A FEW INCHES OF
SWIFTLY FLOWING WATER TO CARRY VEHICLES AWAY.

LAT...LON 3703 11362 3704 11347 3708 11338 3716 11331
      3710 11360

$$
2 follow-up statements
000 
WGUS75 KSLC 241252
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
652 AM MDT TUE JUL 24 2007

UTC053-241430-
WASHINGTON UT-
652 AM MDT TUE JUL 24 2007

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 AM MDT FOR SOUTH
CENTRAL WASHINGTON COUNTY...

AT 644 AM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT THE HEAVY RAIN ALONG THE VIRGIN RIVER DRAINAGE HAD MOVED NORTH 
OF THE WARNING AREA. HEAVY RUNOFF ACROSS THE DRAINAGE WILL RESULT IN 
RAPID AND SIGNIFICANT INCREASES IN STREAM FLOWS ON THE VIRGIN RIVER  
THROUGH 830 AM.

FLOODING ON LOW-LYING AREAS ALONG THE VIRGIN RIVER ARE POSSIBLE. 
AREAS MOST PRONE TO FLOODING WILL BE SOUTH AND SOUTHEAST OF ST. 
GEORGE THROUGH 830 AM THIS MORNING.


LAT...LON 3703 11362 3704 11347 3708 11338 3716 11331
      3710 11360

$$
000 
WGUS75 KSLC 241351
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
749 AM MDT TUE JUL 24 2007

UTC053-241350-
WASHINGTON UT-
749 AM MDT TUE JUL 24 2007

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR SOUTH CENTRAL
WASHINGTON COUNTY...

HEAVY RUNOFF FROM EARLIER THUNDERSTORMS HAS PRODUCED SIGNIFICANT AND 
RAPID INCREASES IN THE FLOW ON THE VIRGIN RIVER NEAR ST. GEORGE. THE 
HEAVY RUNOFF SHOULD REMAIN IN THE RIVER CHANNEL...WITH NO WIDESPREAD 
FLOODING PROBLEMS ANTICIPATED. HIGH FLOWS WILL CONTINUE THROUGH 830 
AM...THEN DECREASE QUICKLY THEREAFTER. 

LAT...LON 3703 11362 3704 11347 3708 11338 3716 11331
      3710 11360

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 24, 4:25 PM MDTFlash Flood WarningSLCWayne3 hr

Nearby

Flash Flood Warnings in Utah, 2007Every flash flood warning in 2007

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.