Alert archive / Utah / Flash Flood Warnings in 2011

Flash Flood Warning 36, NWS Salt Lake City, UT

August 21, 2011Garfield County, Kane County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 21, 2011, 5:09 PM MDT for Garfield County, Kane County, Utah. It was in force for 10 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, 2011, 5:09 PM MDT (23:09 UTC)
Expired: Aug 22, 2011, 2:45 AM MDT
In force: 10 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Flood severity: None

Counties Garfield County, UT, Kane County, UT

The radar

The Cedar City radar (KICX), 137 km from the middle of the area, began a volume at 23:09 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 12:00Z, 11.2 hours before the alert went out and 273 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1956 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 80 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.

634 
WGUS55 KSLC 212309
FFWSLC
UTC017-025-220845-
/O.NEW.KSLC.FF.W.0036.110821T2309Z-110822T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
509 PM MDT SUN AUG 21 2011

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL GARFIELD COUNTY IN UTAH
  NORTHEASTERN KANE COUNTY IN UTAH

* UNTIL 245 AM MDT MONDAY

* AT 452 PM MDT...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL OVER THE UPPER PORTIONS OF THE 
ESCALANTE RIVER DRAINAGE HAS GENERATED A FLASH FLOOD IN THE RIVER 
CHANNEL. GAGE DATA SHOWS A 6 FOOT WALL OF WATER HEADING DOWNSTREAM 
FROM THE TOWN OF ESCALANTE. ADDITIONAL HEAVY RAINFALL JUST 
DOWNSTREAM OF THE TOWN MAY HAVE INCREASED THE SIZE OF THIS FLOOD 
WAVE.

THIS FLOODING IS EXPECTED TO TRAVEL THE LENGTH OF THE ESCALANTE 
RIVER CHANNEL FROM NEAR TOWN ALL THE WAY DOWN TO WHERE THE RIVER 
EMPTIES INTO LAKE POWELL. 

FLASH FLOODING IS ALSO LIKELY OCCURRING IN ALVEY WASH...A MAJOR WASH 
SOUTH OF THE ESCALANTE THAT EVENTUALLY JOINS UP WITH THE ESCALANTE 
RIVER. 

CAMPERS AND HIKERS SHOULD AVOID THE MAINSTEM OF THE ESCALANTE RIVER 
AND ALVEY WASH THE REST OF THIS EVENING AND 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.

FLOODING IS OCCURRING OR IS IMMINENT. IT IS IMPORTANT TO STAY OUT OF 
THE ESCALANTE RIVER CHANNEL TONIGHT. 

&&

LAT...LON 3779 11160 3782 11153 3780 11144 3777 11132
      3769 11121 3761 11112 3751 11099 3742 11095
      3740 11099 3750 11107 3757 11116 3764 11122
      3761 11136 3766 11153 3775 11160 3777 11158

$$

PW

2 follow-up statements

363 
WGUS75 KSLC 220301
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
901 PM MDT SUN AUG 21 2011

UTC017-025-220845-
/O.CON.KSLC.FF.W.0036.000000T0000Z-110822T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
KANE UT-GARFIELD UT-
901 PM MDT SUN AUG 21 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 245 AM MDT FOR SOUTH
CENTRAL GARFIELD AND NORTHEASTERN KANE COUNTIES...

AT 900 PM MDT...A FLOOD WAVE WAS LIKELY STILL MAKING ITS WAY DOWN 
THE ESCALANTE RIVER. THIS WAVE WILL CONTINUE ALL THE WAY DOWN TO 
WHERE THE RIVER EMPTIES INTO LAKE POWELL...ALTHOUGH IT WILL BECOME 
SOMEWHAT SMALLER AND MORE SPREAD OUT AS IT TRAVELS DOWNSTREAM 
TONIGHT.  

WATER WAS ALSO LIKELY STILL RUNNING IN ALVEY WASH. 

CAMPERS AND HIKERS SHOULD AVOID THE MAINSTEM OF THE ESCALANTE RIVER 
DOWNSTREAM FROM THE CROSSING UNDER STATE ROUTE 12 AND ALVEY WASH FOR 
THE REST OF THE NIGHT. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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. MOVE TO HIGHER GROUND.

&&

LAT...LON 3779 11160 3782 11153 3780 11144 3777 11132
      3769 11121 3761 11112 3751 11099 3742 11095
      3740 11099 3750 11107 3757 11116 3764 11122
      3761 11136 3766 11153 3775 11160 3777 11158

$$

PW

170 
WGUS75 KSLC 220849
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
249 AM MDT MON AUG 22 2011

UTC017-025-220855-
/O.EXP.KSLC.FF.W.0036.000000T0000Z-110822T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
KANE UT-GARFIELD UT-
249 AM MDT MON AUG 22 2011

...THE FLASH FLOOD WARNING HAS EXPIRED FOR SOUTH CENTRAL GARFIELD AND
NORTHEASTERN KANE COUNTIES...

RUNOFF FROM EARLIER HEAVY PRECIPITATION HAS DIMINISHED. RUNOFF FROM 
THE EARLIER HEAVY RAIN MAY STILL BE FLOWING AT ELEVATED LEVELS NEAR 
THE ENTRANCE OF THE WATERWAY TO LAKE POWELL. ANY RESIDUAL MINOR 
FLOODING NEAR THE LAKE SHOULD END SHORTLY. 

LAT...LON 3779 11160 3782 11153 3780 11144 3777 11132
      3769 11121 3761 11112 3751 11099 3742 11095
      3740 11099 3750 11107 3757 11116 3764 11122
      3761 11136 3766 11153 3775 11160 3777 11158

$$

CONGER

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 6:39 PM MDT	Severe Thunderstorm Warning	SLC	Davis, Salt Lake	21 min
Aug 21, 3:04 PM MDT	Flash Flood Warning	SLC	Garfield	3 hr
Aug 21, 5:37 PM MDT	Areal Flood Advisory	SLC	Wayne	113 min

Nearby

Flash Flood Warnings in Utah, 2011 Every 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.