Alert archive / Arizona / Flash Flood Warnings in 2011

Flash Flood Warning 34, NWS Las Vegas, NV

July 7, 2011Mohave County, Arizona; Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Jul 7, 2011, 3:35 PM MST for Mohave County, Arizona; Clark County, Nevada. It was in force for 114 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 7, 2011, 3:35 PM MST (22:35 UTC)
Expired
Jul 7, 2011, 5:29 PM MST
In force
114 min
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

Counties Mohave County, AZ, Clark County, NV

The radar

The Las Vegas radar (KESX), 38 km from the middle of the area, began a volume at 22:39 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.

What was reported inside it

TimeReportWhereRemark
Jul 7, 3:39 PM MSTFLASH FLOOD1 Se Boulder City, NVSPOTTER REPORTS SIX INCHES OF WATER AND ROCKS ACROSS HIGHWAY 93 AT SEVERAL PLACES IN BOULDER CITY.
Jul 7, 4:10 PM MSTFLASH FLOODBoulder City, NVMUD AND DEBRIS ACROSS THE ROADWAY AT PACIFICA IN BOULDER CITY.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Las Vegas, NV (KVEF), launched 12:00Z, 10.6 hours before the alert went out and 74 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 2011-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 34 joules per kilogram.LCLLFCEL10008507005003002001001 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 2011-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 square meters per square second.1939Sfc1 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
34 J/kg
Mixed-layer CIN
-208 J/kg
Mixed-layer LCL
2113 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
114 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.

436 
WGUS55 KVEF 072235
FFWVEF
AZC015-NVC003-080130-
/O.NEW.KVEF.FF.W.0034.110707T2235Z-110708T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
335 PM PDT THU JUL 7 2011

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EXTREME WEST CENTRAL MOHAVE COUNTY IN NORTHWEST ARIZONA...
  CENTRAL CLARK COUNTY IN SOUTHERN NEVADA...

* UNTIL 630 PM PDT/630 PM MST/.

* AT 329 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
VERY HEAVY RAIN FROM A LARGE AREA OF THUNDERSTORMS STRETCHING FROM 
NEAR BOULDER CITY TO NEAR BOULDER BEACH.

* LOCATIONS IMPACTED INCLUDE...BOULDER BEACH...BOULDER CITY...HOOVER 
DAM...LAS VEGAS BAY...HIGHWAY 93 FROM MILE MARKER 59 TO JUST EAST OF 
THE NEVADA ARIZONA BORDER...LAKE SHORE ROAD...RAILROAD PASS AND 
BOULDER BEACH CAMPGROUND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED IN WASHES...LOW WATER CROSSINGS AND ON
AREA ROADWAYS. FLASH FLOODING IS NATURES NUMBER ONE KILLER. TO ESCAPE
RISING WATER...MOVE TO HIGHER GROUND. NEVER TRY TO CROSS A FLOODED
ROADWAY OR WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE OR TWITTER #NWSVEGAS.

&&

LAT...LON 3614 11485 3602 11470 3589 11482 3600 11495

$$

JGG
3 follow-up statements
226 
WGUS75 KVEF 072246
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
346 PM PDT THU JUL 7 2011

AZC015-NVC003-080130-
/O.CON.KVEF.FF.W.0034.000000T0000Z-110708T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MOHAVE AZ-CLARK NV-
346 PM PDT THU JUL 7 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM PDT/630 PM
MST/ FOR CENTRAL CLARK AND EXTREME WEST CENTRAL MOHAVE COUNTIES...

AT 339 PM PDT...TRAINED WEATHER SPOTTERS REPORTED SIX INCHES OF 
WATER OVER HIGHWAY 93 IN BOULDER CITY. RADAR CONTINUES TO INDICATE 
VERY HEAVY RAIN ACROSS ALMOST ALL OF THE AREA FROM BOULDER BEACH TO 
BOULDER CITY AND SOUTH OF LAS VEGAS BAY. 

LOCATIONS IMPACTED INCLUDE...BOULDER BEACH...BOULDER CITY...HOOVER 
DAM...LAS VEGAS BAY...RAILROAD PASS...HIGHWAY 93 FROM MILE MARKER 59 
TO JUST EAST OF THE NEVADA ARIZONA BORDER...LAKE SHORE ROAD...AND 
BOULDER BEACH CAMPGROUND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED ON AREA ROADWAYS...AROUND UNDERPASSES...
AND IN NORMALLY DRY WASHES AND LOW LYING AREAS. FLASH FLOODING IS
NATURES NUMBER ONE KILLER. NEVER TRY TO CROSS A FLOODED ROADWAY OR
WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE OR TWITTER #NWSVEGAS.

FLASH FLOODING IS EXPECTED IN WASHES...LOW WATER CROSSINGS AND ON
AREA ROADWAYS. FLASH FLOODING IS NATURES NUMBER ONE KILLER. TO ESCAPE
RISING WATER...MOVE TO HIGHER GROUND. NEVER TRY TO CROSS A FLOODED
ROADWAY OR WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE OR TWITTER #NWSVEGAS.

&&

LAT...LON 3614 11485 3602 11470 3589 11482 3600 11495

$$

JGG
687 
WGUS75 KVEF 072340
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
440 PM PDT THU JUL 7 2011

AZC015-NVC003-080130-
/O.CON.KVEF.FF.W.0034.000000T0000Z-110708T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MOHAVE AZ-CLARK NV-
440 PM PDT THU JUL 7 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM PDT/630 PM
MST/ FOR CENTRAL CLARK AND EXTREME WEST CENTRAL MOHAVE COUNTIES...

AT 435 PM PDT...LOCAL LAW ENFORCEMENT REPORTED MUD AND DEBRIS ACROSS 
SOME ROADWAYS IN BOULDER CITY. WHILE RAIN HAS ENDED IN THE BOULDER 
CITY...BOULDER BEACH...AND LAS VEGAS BAY AREAS FOR NOW...ADDITIONAL 
RAINFALL IS MOVING IN FROM THE SOUTHWEST AND MAY CAUSE ADDITIONAL 
FLOODING OR AGGRAVATE EXISTING CONDITIONS.

LOCATIONS IMPACTED INCLUDE...BOULDER BEACH...BOULDER CITY...HOOVER
DAM...LAS VEGAS BAY...RAILROAD PASS AND BOULDER BEACH CAMPGROUND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED ON AREA ROADWAYS...AROUND UNDERPASSES...
AND IN NORMALLY DRY WASHES AND LOW LYING AREAS. FLASH FLOODING IS
NATURES NUMBER ONE KILLER. NEVER TRY TO CROSS A FLOODED ROADWAY OR
WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE OR TWITTER #NWSVEGAS.

FLASH FLOODING IS EXPECTED IN WASHES...LOW WATER CROSSINGS AND ON
AREA ROADWAYS. FLASH FLOODING IS NATURES NUMBER ONE KILLER. TO ESCAPE
RISING WATER...MOVE TO HIGHER GROUND. NEVER TRY TO CROSS A FLOODED
ROADWAY OR WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE OR TWITTER #NWSVEGAS.

&&

LAT...LON 3614 11485 3602 11470 3589 11482 3600 11495

$$

JGG
105 
WGUS75 KVEF 080029
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
529 PM PDT THU JUL 7 2011

AZC015-NVC003-080039-
/O.CAN.KVEF.FF.W.0034.000000T0000Z-110708T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MOHAVE AZ-CLARK NV-
529 PM PDT THU JUL 7 2011

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL CLARK AND
EXTREME WEST CENTRAL MOHAVE COUNTIES...

RAINFALL HAS ENDED IN THE AREA AND LOCAL LAW ENFORCEMENT REPORT NO 
CONTINUING FLASH FLOOD PROBLEMS...THEREFORE THE WARNING IS CANCELLED.

ADDITIONAL SHOWERS AND STORMS WILL BE POSSIBLE THIS EVENING.

LAT...LON 3614 11485 3602 11470 3589 11482 3600 11495

$$

JGG

The office that day

Everything else NWS Las Vegas, NV issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 7, 2:54 PM MSTSevere Thunderstorm WarningVEFMohave51 min
Jul 7, 3:18 PM MSTSevere Thunderstorm WarningVEFMohave42 min
Jul 7, 3:32 PM MSTSevere Thunderstorm WarningVEFMohave43 min
Jul 6, 5:48 PM MSTAreal Flood AdvisoryVEFClark, Nye71 min
Jul 7, 1:01 PM MSTAreal Flood AdvisoryVEFClark43 min
Jul 7, 1:16 PM MSTFlash Flood WarningVEFClark119 min
Jul 7, 3:01 PM MSTSevere Thunderstorm WarningVEFClark33 min
Jul 7, 4:26 PM MSTAreal Flood AdvisoryVEFClark74 min
Jul 7, 4:29 PM MSTSevere Thunderstorm WarningVEFClark46 min
Jul 7, 4:37 PM MSTFlash Flood WarningVEFClark53 min
Jul 7, 4:52 PM MSTFlash Flood WarningVEFClark113 min

Nearby

Flash Flood Warnings in Arizona, 2011Flash Flood Warnings in Nevada, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.