Alert archive / Utah / Flash Flood Warnings in 2011

Flash Flood Warning 34, NWS Salt Lake City, UT

August 20, 2011Garfield County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 20, 2011, 1:27 PM MDT for Garfield 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 20, 2011, 1:27 PM MDT (19:27 UTC)
Expired: Aug 20, 2011, 4:15 PM MDT
In force: 3 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Flood severity: None

County Garfield County, UT

The radar

The Cedar City radar (KICX), 104 km from the middle of the area, began a volume at 19:30 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, 7.5 hours before the alert went out and 290 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: 183 J/kg
Mixed-layer CIN: -87 J/kg
Mixed-layer LCL: 1262 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 19 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.

562 
WGUS55 KSLC 201927
FFWSLC
UTC017-202215-
/O.NEW.KSLC.FF.W.0034.110820T1927Z-110820T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
127 PM MDT SAT AUG 20 2011

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL GARFIELD COUNTY IN UTAH
  INCLUDING NORTH CREEK NEAR ESCALANTE

* UNTIL 415 PM MDT

* AT 115 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  THAT VERY HEAVY RAIN HAD BEEN FALLING IN THE HEADWATERS OF NORTH 
  CREEK JUST NORTH OF ESCALANTE.  RADAR ESTIMATES INDICATE THAT AS 
  MUCH AS 2 TO 3 INCHES OF RAIN HAS FALLEN IN THIS AREA SINCE LATE 
  THIS MORNING. 

* RUNOFF FROM THIS HEAVY RAIN WILL RESULT IN FLASH FLOODING ON AREA 
  WASHES AND SMALL STREAMS...INCLUDING NORTH CREEK AND EAST FORK 
  NORTH OF ESCALANTE. THE RUNOFF FROM THIS HEAVY RAIN WILL           
  EVENTUALLY REACH THE ESCALANTE RIVER. 

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 3784 11178 3793 11184 3797 11177 3786 11173
      3779 11169 3779 11159 3777 11159 3774 11173

$$

RG

2 follow-up statements

803 
WGUS75 KSLC 202122
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
322 PM MDT SAT AUG 20 2011

UTC017-202215-
/O.CON.KSLC.FF.W.0034.000000T0000Z-110820T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GARFIELD UT-
322 PM MDT SAT AUG 20 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM MDT FOR 
CENTRAL GARFIELD COUNTY INCLUDING NORTH CREEK...

NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THAT VERY HEAVY 
RAIN FELL OVER THE HEADWATERS OF NORTH CREEK JUST NORTH OF ESCALANTE 
EARLIER TODAY.  RADAR ESTIMATES INDICATE THAT AS MUCH AS 2 TO 4 
INCHES OF RAIN FELL IN THIS AREA. RAPID RUNOFF FROM THESE STORMS IS 
EXPECTED TO RESULT IN RAPID RISES ON AREA STREAMS AND WASHES... 
PARTICULARLY ALONG NORTH CREEK AND IN THE EAST FORK DRAINAGE. 

ALTHOUGH THE HEAVY RAIN HAS ENDED...RUNOFF FROM THESE EARLIER STORMS 
IS STILL MOVING DOWN AREA DRAINAGES...INCLUDING NORTH CREEK.  
ADDITIONAL SHOWERS AND THUNDERSTORMS MAY BRING ADDITIONAL RAIN TO 
THE AREA THIS AFTERNOON.

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 3784 11178 3793 11184 3797 11177 3786 11173
      3779 11169 3779 11159 3777 11159 3774 11173

$$

RG

462 
WGUS75 KSLC 202217
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
417 PM MDT SAT AUG 20 2011

UTC017-202224-
/O.EXP.KSLC.FF.W.0034.000000T0000Z-110820T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GARFIELD UT-
417 PM MDT SAT AUG 20 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 415 PM MDT FOR CENTRAL
GARFIELD COUNTY...

RUNOFF FROM EARLIER PRECIPITATION HAS DIMINISHED AND WATER LEVELS IN 
NORTH CREEK AND EAST FORK DRAINAGES NORTHWEST OF ESCALANTE HAVE 
DIMINISHED. THEREFORE...THE FLASH FLOOD WARNING HAS BEEN ALLOWED TO 
EXPIRE. 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 3784 11178 3793 11184 3797 11177 3786 11173
      3779 11169 3779 11159 3777 11159 3774 11173

$$

RG

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 19, 6:12 PM MDT	Flash Flood Warning	SLC	Garfield	3 hr
Aug 20, 2:44 PM MDT	Areal Flood Advisory	SLC	Garfield	3 hr
Aug 20, 4:30 PM MDT	Areal Flood Advisory	SLC	Garfield, Kane	3 hr

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.