Alert archive / Utah / Flash Flood Warnings in 2011

Flash Flood Warning 5, NWS Salt Lake City, UT

July 8, 2011Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 8, 2011, 8:40 PM MDT for Washington County, Utah. It was in force for 5 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: Jul 8, 2011, 8:40 PM MDT (02:40 UTC)
Expired: Jul 9, 2011, 1:45 AM MDT
In force: 5 hr
Issued by: NWS Salt Lake City, UT
Area: Storm-based polygon
Flood severity: None

County Washington County, UT

The radar

The Cedar City radar (KICX), 106 km from the middle of the area, began a volume at 02:42 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 00:00Z, 2.7 hours before the alert went out and 169 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: 3462 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 6 m²/s²
0-3 km storm-relative helicity: 26 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.

835 
WGUS55 KSLC 090240
FFWSLC
UTC053-090745-
/O.NEW.KSLC.FF.W.0005.110709T0240Z-110709T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
840 PM MDT FRI JUL 8 2011

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  BEAVER DAM WASH IN SOUTHWESTERN WASHINGTON COUNTY IN UTAH...

* UNTIL 145 AM MDT

* AT 833 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  THUNDERSTORMS PRODUCING VERY HEAVY RAINFALL ACROSS THE UPPER 
  PORTIONS OF BEAVER DAM WASH...WITH ADDITIONAL THUNDERSTORMS LIKELY 
  THROUGH 10 PM. RUNOFF FROM THIS HEAVY RAINFALL WILL LIKELY RESULT 
  IN FLASH FLOODING ALONG BEAVER DAM WASH FROM MOTOQUA SOUTH TO THE 
  ARIZONA BORDER. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BEAVER DAM 
  WASH...MOTOQUA AND GOLDSTRIKE

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 3746 11404 3742 11385 3718 11397 3701 11397
      3701 11405

$$

SEAMAN

2 follow-up statements

503 
WGUS75 KSLC 090441
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1041 PM MDT FRI JUL 8 2011

UTC053-090745-
/O.CON.KSLC.FF.W.0005.000000T0000Z-110709T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
1041 PM MDT FRI JUL 8 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 145 AM MDT FOR THE 
BEAVER DAM WASH IN SOUTHWESTERN WASHINGTON COUNTY...

AT 1034 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR ESTIMATED A 
WIDESPREAD 1 TO 2 INCHES OF RAIN HAD FALLEN ACROSS THE UPPER HALF OF 
THE BEAVER DAM WASH DRAINAGE. ALTHOUGH RAINFALL HAS 
DIMINISHED...THIS RUNOFF WILL CONTINUE TO WORK ITS WAY DOWN THE WASH 
THROUGH EARLY SATURDAY MORNING. 

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BEAVER DAM 
WASH...MOTOQUA AND GOLDSTRIKE

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 3746 11404 3742 11385 3718 11397 3701 11397
      3701 11405

$$

SEAMAN

489 
WGUS75 KSLC 090748
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
148 AM MDT SAT JUL 9 2011

UTC053-090755-
/O.EXP.KSLC.FF.W.0005.000000T0000Z-110709T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
148 AM MDT SAT JUL 9 2011

...THE FLASH FLOOD WARNING HAS EXPIRED FOR THE BEAVER DAM WASH 
SOUTHWESTERN WASHINGTON COUNTY...

RUNOFF FROM EARLIER PRECIPITATION HAS DIMINISHED GREATLY AND 
SIGNIFICANT FLASH FLOODING IS NO LONGER EXPECTED ALONG THE BEAVER 
DAM WASH. SOME RISES IN WATER LEVELS ARE STILL POSSIBLE AS RUNOFF 
FROM EARLIER RAINFALL CONTINUES TO WORK ITS WAY DOWN THE WASH. 

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 3746 11404 3742 11385 3718 11397 3701 11397
      3701 11405

$$

PW

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 8, 7:15 PM MDT	Areal Flood Advisory	SLC	Garfield, Iron	3 hr
Jul 8, 9:08 PM MDT	Special Weather Statement	SLC	Washington	67 min
Jul 9, 12:10 PM MDT	Special Weather Statement	SLC	Wayne	50 min
Jul 9, 5:02 PM MDT	Special Weather Statement	SLC	Tooele	43 min
Jul 9, 5:31 PM MDT	Severe Thunderstorm Warning	SLC	Box Elder	59 min
Jul 9, 5:42 PM MDT	Special Weather Statement	SLC	Davis	48 min
Jul 9, 5:57 PM MDT	Severe Thunderstorm Warning	SLC	Box Elder, Weber	33 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.