Alert archive / Utah / Flash Flood Warnings in 2011

Flash Flood Warning 42, NWS Salt Lake City, UT

August 25, 2011Kane County, Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 25, 2011, 5:31 PM MDT for Kane County, Washington County, Utah. It was in force for 3 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 25, 2011, 5:31 PM MDT (23:31 UTC)
Expired
Aug 25, 2011, 8:30 PM MDT
In force
3 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), 42 km from the middle of the area, began a volume at 23:34 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

Las Vegas, NV (KVEF), launched 12:00Z, 11.5 hours before the alert went out and 242 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, Las Vegas, NV at 12:00Z on 2011-08-25Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Las Vegas, NV at 12:00Z on 2011-08-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -26 square meters per square second.193958Sfc1 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
3885 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-26 m²/s²
0-3 km storm-relative helicity
47 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.

074 
WGUS55 KSLC 252331
FFWSLC
UTC025-053-260230-
/O.NEW.KSLC.FF.W.0042.110825T2331Z-110826T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
531 PM MDT THU AUG 25 2011

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...SPECIFICALLY FOR THE      
  NORTH FORK OF THE VIRGIN RIVER...OAK CREEK AND EMERALD POOL IN     
  ZION NATIONAL PARK.

* UNTIL 830 PM MDT

* AT 522 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  HEAVY RAIN FROM A THUNDERSTORM OVER THE NORTH FORK OF THE VIRGIN   
  RIVER...OAK CREEK AND EMERALD POOL IN ZION NATIONAL PARK.

* VERY HEAVY RAINFALL HAS OCCURRED OVER THE LAST HOUR WITH           
  PRECIPITATION ESTIMATES OF 1 TO 1.5 INCHES OF RAINFALL FALLING     
  WITHIN THAT TIME. ADDITIONAL HEAVY RAIN WILL OCCUR AND             
  FLASH FLOODING IS EXPECTED IN THE ABOVE MENTIONED AREAS AND OTHER  
  SLOT CANYONS IN THE VICINITY.

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.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN SALT
LAKE CITY.

&&

LAT...LON 3720 11312 3719 11305 3740 11303 3740 11288
      3714 11297 3716 11313

$$

MERRILL
1 follow-up statement
348 
WGUS75 KSLC 260120
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
720 PM MDT THU AUG 25 2011

UTC025-053-260230-
/O.CON.KSLC.FF.W.0042.000000T0000Z-110826T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-KANE UT-
720 PM MDT THU AUG 25 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM MDT FOR WEST
CENTRAL KANE AND EAST CENTRAL WASHINGTON COUNTIES...

AT 704 PM MDT...RADAR ESTIMATES THAT UP TO 2 INCHES OF RAIN HAS 
FALLEN FROM THUNDERSTORMS ACROSS ZION NATIONAL PARK EARLIER THIS 
EVENING. RUNOFF FROM THIS HEAVY RAIN WILL CONTINUE TO RESULT IN HIGH 
FLOWS ALONG SMALL STREAMS AND IN SLOT CANYONS. 

LOCATIONS IN THE WARNING INCLUDE THE NORTH FORK OF THE VIRGIN 
RIVER...OAK CREEK AND EMERALD POOL IN ZION NATIONAL PARK.

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 3720 11312 3719 11305 3740 11303 3740 11288
      3714 11297 3716 11313

$$

CHENG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 25, 3:25 PM MDTFlash Flood WarningSLCWayne3 hr

Nearby

Flash Flood Warnings in Utah, 2011Every flash flood warning in 2011

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.