Alert archive / Utah / Flash Flood Warnings in 2012

Flash Flood Warning 33, NWS Salt Lake City, UT

July 31, 2012Kane County, Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 31, 2012, 5:25 PM MDT for Kane County, Washington County, Utah. It was in force for 4 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: Jul 31, 2012, 5:25 PM MDT (23:25 UTC)
Expired: Jul 31, 2012, 9:15 PM MDT
In force: 4 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Flood severity: None

Counties Kane County, UT, Washington County, UT

The radar

The Cedar City radar (KICX), 39 km from the middle of the area, began a volume at 23:26 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
Jul 31, 5:39 PM MDT	FLASH FLOOD	Zion Np, UT	SIGNIFICANT FLASH FLOODING IN ZION NP.

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

The nearest sounding before it

Las Vegas, NV (KVEF), launched 12:00Z, 11.4 hours before the alert went out and 246 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: 121 J/kg
Mixed-layer CIN: -75 J/kg
Mixed-layer LCL: 1334 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -5 m²/s²
0-3 km storm-relative helicity: -43 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.

011 
WGUS55 KSLC 312325
FFWSLC
UTC025-053-010315-
/O.NEW.KSLC.FF.W.0033.120731T2325Z-120801T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
525 PM MDT TUE JUL 31 2012

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

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

* UNTIL 915 PM MDT

* AT 524 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
HEAVY RAIN FROM A THUNDERSTORM OVER ZION NATIONAL PARK. RADAR 
RAINFALL ESTIMATES INDICATE VERY INTENSE RAINFALL OVER A LARGE 
SECTION OF THE PARK. 

AREAS OF CONCERN INCLUDE THE NORTH FORK AND EAST FORK DRAINAGES OF 
ZION NATIONAL PARK.  THESE AREAS ARE VERY FLASH FLOOD PRONE AND WITH 
THE AMOUNT OF INTENSE RAIN FALLING...THESE AREAS COULD BECOME QUITE 
DANGEROUS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE TRAVELING THROUGH THIS AREA...PLEASE ENSURE FOR YOUR 
SAFETY.

&&

LAT...LON 3737 11310 3737 11288 3722 11280 3715 11287
      3716 11309 3720 11319

$$

MCINERNEY

2 follow-up statements

882 
WGUS75 KSLC 010109
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
709 PM MDT TUE JUL 31 2012

UTC025-053-010315-
/O.CON.KSLC.FF.W.0033.000000T0000Z-120801T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-KANE UT-
709 PM MDT TUE JUL 31 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 915 PM MDT FOR WEST
CENTRAL KANE AND EAST CENTRAL WASHINGTON COUNTIES...

AT 706 PM MDT...FLASH FLOODING WAS REPORTED THROUGHOUT ZION NATIONAL 
PARK. MANY SLOT CANYONS ARE CURRENTLY FLOODING AND CAN BE EXPECTED 
TO RUN HIGH AND DANGEROUS THROUGH 915PM. 

SOME OF THE WATERWAYS THAT ARE CURRENTLY FLASHING INCLUDE THE NORTH 
AND EAST FORKS OF THE VIRGIN RIVER...CLEAR CREEK...AND KOLOB CREEK.

ALTHOUGH THUNDERSTORM ACTIVITY HAS DECREASED OVER THE AREA...THESE 
WATERWAYS WILL REQUIRE AN ADDITIONAL TWO HOURS TO DEWATER. UNTIL 
THAT TIME...PLEASE USE PRUDENT JUDGEMENT IF YOU ARE NEAR THESE 
DANGEROUS WATERS.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO ZION NATIONAL
PARK

LAT...LON 3737 11310 3737 11288 3722 11280 3715 11287
      3716 11309 3720 11319

$$

MCINERNEY

787 
WGUS75 KSLC 010310
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
910 PM MDT TUE JUL 31 2012

UTC025-053-010316-
/O.EXP.KSLC.FF.W.0033.000000T0000Z-120801T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-KANE UT-
910 PM MDT TUE JUL 31 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 915 PM MDT FOR WEST CENTRAL
KANE AND EAST CENTRAL WASHINGTON COUNTIES...

FLASH FLOODING HAD BEEN REPORTED THROUGHOUT ZION NATIONAL PARK AND 
THE RIVER GAGE ON THE NORTH FORK OF THE VIRGIN RIVER SHOWED A 
SIGNIFICANT RISE...FROM NEAR 55 CFS TO 1433 CFS.

HOWEVER...RUNOFF FROM THE EARLIER PRECIPITATION HAS DIMINISHED AND 
RIVER AND STREAM LEVELS WILL CONTINUE TO LOWER. THEREFORE...THE 
FLASH FLOOD WARNING HAS BEEN ALLOWED TO EXPIRE. MONITOR NOAA WEATHER 
RADIO OR LOCAL TELEVISION OR RADIO FOR THE LATEST WEATHER 
INFORMATION.

LAT...LON 3737 11310 3737 11288 3722 11280 3715 11287
      3716 11309 3720 11319

$$

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, 3:35 AM MDT	Flash Flood Watch	SLC		18 hr
Jul 31, 1:55 PM MDT	Flash Flood Warning	SLC	Carbon, Emery	4 hr
Jul 31, 3:00 PM MDT	Flash Flood Warning	SLC	Wayne	4 hr
Jul 31, 5:14 PM MDT	Areal Flood Advisory	SLC	Washington	65 min

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.