Alert archive / Utah / Flash Flood Warnings in 2011

Flash Flood Warning 18, NWS Salt Lake City, UT

July 31, 2011Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 31, 2011, 5:12 PM MDT for 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: Jul 31, 2011, 5:12 PM MDT (23:12 UTC)
Expired: Jul 31, 2011, 8:15 PM MDT
In force: 3 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), 41 km from the middle of the area, began a volume at 23:13 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, 11.2 hours before the alert went out and 237 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: 8 J/kg
Mixed-layer CIN: -233 J/kg
Mixed-layer LCL: 2632 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 0 m²/s²
0-3 km storm-relative helicity: 20 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.

686 
WGUS55 KSLC 312312
FFWSLC
UTC053-010215-
/O.NEW.KSLC.FF.W.0018.110731T2312Z-110801T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
512 PM MDT SUN JUL 31 2011

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

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

* UNTIL 815 PM MDT

* AT 508 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
THUNDERSTORMS CAPABLE OF PRODUCING FLASH FLOODING OVER THE NORTH 
CREEK IN AND NEAR ZION NATIONAL PARK.

* UP TO 1.25 INCHES OF RAIN HAS FALLEN ACROSS THIS AREA IN THE PAST 
30 MINUTES. FLASH FLOODING IS EXPECTED ALONG THE LEFT AND RIGHT FORK 
OF NORTH CREEK THROUGH THEIR CONFLUENCE AND THEN ALONG NORTH CREEK 
TO THE CONFLUENCE WITH THE VIRGIN 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 3735 11318 3736 11300 3718 11312 3720 11318

$$

KRUSE

2 follow-up statements

586 
WGUS75 KSLC 010032
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
632 PM MDT SUN JUL 31 2011

UTC053-010215-
/O.CON.KSLC.FF.W.0018.000000T0000Z-110801T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
632 PM MDT SUN JUL 31 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM MDT FOR EAST
CENTRAL WASHINGTON COUNTY...

AT 625 PM MDT...ADDITIONAL MODERATE RAINFALL REMAINS POSSIBLE ACROSS 
THE NORTH FORK CREEK AREA INCLUDING PORTIONS OF ZION NATIONAL PARK.

RADAR ESTIMATES OF UP TO 1.25 INCHES HAVE OCCURRED IN THIS AREA OVER 
THE PAST SEVERAL HOURS.

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 3735 11318 3736 11300 3718 11312 3720 11318

$$

KRUSE

129 
WGUS75 KSLC 010216
FFSSLC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
816 PM MDT SUN JUL 31 2011

UTC053-010222-
/O.EXP.KSLC.FF.W.0018.000000T0000Z-110801T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON UT-
816 PM MDT SUN JUL 31 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 815 PM MDT FOR EAST CENTRAL
WASHINGTON COUNTY...

THUNDERSTORMS THAT BROUGHT HEAVY RAIN TO THE LEFT AND RIGHT FORKS OF 
NORTH CREEK HAVE MOVED AWAY AND THE THREAT OF FLASH FLOODING HAS 
DIMINISHED. HOWEVER...SHOWERS AND ISOLATED THUNDERSTORMS WILL 
CONTINUE IN THIS AREA FOR ANOTHER FEW HOURS SO CAUTION SHOULD BE 
USED WHILE TRAVELING IN THIS AREA.

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 3735 11318 3736 11300 3718 11312 3720 11318

$$

STRUTHWOLF

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 4:04 AM MDT	Flash Flood Watch	SLC		17 hr
Jul 31, 1:43 PM MDT	Areal Flood Advisory	SLC	Kane, Washington	3 hr
Jul 31, 3:45 PM MDT	Areal Flood Advisory	SLC	Beaver, Iron	3 hr
Jul 31, 4:02 PM MDT	Special Weather Statement	SLC	Garfield	43 min
Jul 31, 4:49 PM MDT	Flash Flood Warning	SLC	Garfield	6 hr
Jul 31, 5:52 PM MDT	Flash Flood Warning	SLC	Wayne	3 hr
Jul 31, 5:53 PM MDT	Areal Flood Advisory	SLC	Kane, Washington	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.