Alert archive / Nevada / Flash Flood Warnings in 2011

Flash Flood Warning 87, NWS Las Vegas, NV

September 13, 2011Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Sep 13, 2011, 8:01 AM PDT for Clark County, Nevada. It was in force for 119 min. 4 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
Sep 13, 2011, 8:01 AM PDT (15:01 UTC)
Expired
Sep 13, 2011, 10:00 AM PDT
In force
119 min
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County Clark County, NV

The radar

The Las Vegas radar (KESX), 44 km from the middle of the area, began a volume at 15:01 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
Sep 13, 8:04 AM PDTFLASH FLOOD1 Se East Las Vegas, NVWATER WAS REPORTED FLOWING ACROSS THE INTERSECTION OF BOULDER HIGHWAY AND RUSSEL ROAD AND SPILLING OVER INTO A NEARBY FLOOD CHANNEL.
Sep 13, 9:00 AM PDTFLASH FLOOD3 Sse Henderson, NVFLOODWATERS BUILT UP BEHIND A BACKYARD WALL AT A HOME IN HENDERSON NEAR HORIZON RIDGE AND MISSION AND STRAINED THE WALL TO THE POINT THAT IT BROKE. A FOUR FOOT WALL OF WATER AND MUD RUSHED INTO THE YARD OF A HOME...FLOODING MOST OF THE FIRST FLOOR AND INUNDATI
Sep 13, 9:00 AM PDTFLASH FLOOD5 Se Henderson, NVROCKS...DEBRIS AND MUD WERE ON SOME ROADS NEAR US 95 AND WAGON WHEEL DRIVE. ROAD CREWS HAD TO USE A BULLDOZER TO REMOVE IT FROM THE ROADS.
Sep 13, 9:00 AM PDTFLASH FLOOD5 Se Henderson, NVROCKS...DEBRIS AND MUD WERE ON SOME ROADS NEAR US 95 AND WAGON WHEEL DRIVE. ROAD CREWS HAD TO USE A BULLDOZER TO REMOVE TO REMOVE IT FROM THE ROADS.

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, 3.0 hours before the alert went out and 51 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 2011-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 239 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 2011-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 75 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
239 J/kg
Mixed-layer CIN
-98 J/kg
Mixed-layer LCL
1707 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
136 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

732 
WGUS55 KVEF 131501
FFWVEF
NVC003-131700-
/O.NEW.KVEF.FF.W.0087.110913T1501Z-110913T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
801 AM PDT TUE SEP 13 2011

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL CLARK COUNTY IN SOUTHERN NEVADA...

* UNTIL 1000 AM PDT.

* AT 756 AM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR SILVERADO RANCH...OR 9 
  MILES WEST OF HENDERSON. STORMS PRODUCING VERY HEAVY RAIN WERE 
  DEVELOPING OVER MUCH OF THE SOUTHERN LAS VEGAS VALLEY...AND WILL 
  CAUSE FLASH FLOODING.

* LOCATIONS IMPACTED INCLUDE...
  HENDERSON...GREEN VALLEY...MCCARRAN INTERNATIONAL AIRPORT...UNLV...
  SPRING VALLEY...EAST LAS VEGAS AND SAM BOYD STADIUM.

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.

&&

LAT...LON 3612 11530 3610 11492 3592 11492 3594 11532

$$

MORGAN
4 follow-up statements
359 
WGUS75 KVEF 131527
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
827 AM PDT TUE SEP 13 2011

NVC003-131700-
/O.CON.KVEF.FF.W.0087.000000T0000Z-110913T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
827 AM PDT TUE SEP 13 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1000 AM PDT FOR
CENTRAL CLARK COUNTY...

AT 823 AM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE THUNDERSTORMS PRODUCING VERY HEAVY RAIN OVER THE SOUTHERN 
LAS VEGAS VALLEY...ESPECIALLY IN THE HENDERSON AREA. AT 804 
AM...FLOODING WAS REPORTED AT BOULDER HIGHWAY AND RUSSELL ROAD. VERY 
HEAVY RAIN WILL CONTINUE IN THE HENDERSON AREA...AND ADDITIONAL 
FLASH FLOODING IS LIKELY.

LOCATIONS IMPACTED INCLUDE...
HENDERSON...GREEN VALLEY...MCCARRAN INTERNATIONAL AIRPORT...UNLV...
EAST LAS VEGAS...SAM BOYD STADIUM AND SPRING VALLEY.

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.

&&

LAT...LON 3612 11530 3610 11492 3592 11492 3594 11532

$$

MORGAN
937 
WGUS75 KVEF 131552
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
852 AM PDT TUE SEP 13 2011

NVC003-131700-
/O.CON.KVEF.FF.W.0087.000000T0000Z-110913T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
852 AM PDT TUE SEP 13 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1000 AM PDT FOR
CENTRAL CLARK COUNTY...

AT 845 AM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE THUNDERSTORMS PRODUCING VERY HEAVY RAIN OVER HENDERSON. 
FLOODING HAD ALREADY BEEN REPORTED AT BOULDER HIGHWAY AND RUSSELL 
ROAD...AND EXTREMELY HEAVY RAIN WAS FALLING AT THE INTERCHANGE OF 
HIGHWAYS 215 AND 515. FURTHER FLASH FLOODING IS LIKELY IN THIS AREA.

LOCATIONS IMPACTED INCLUDE...
HENDERSON...GREEN VALLEY...MCCARRAN INTERNATIONAL AIRPORT...UNLV...
EAST LAS VEGAS AND SAM BOYD STADIUM.

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.

&&

LAT...LON 3611 11521 3610 11492 3592 11492 3594 11513

$$

MORGAN
843 
WGUS75 KVEF 131627
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
927 AM PDT TUE SEP 13 2011

NVC003-131700-
/O.CON.KVEF.FF.W.0087.000000T0000Z-110913T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
927 AM PDT TUE SEP 13 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1000 AM PDT FOR
CENTRAL CLARK COUNTY...

AT 921 AM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT RAIN WAS ENDING OVER THE HENDERSON AREA. HOWEVER...SIGNIFICANT 
FLOODING WAS OCCURRING IN THE AREA...AND WILL CONTINUE UNTIL 10 AM.

LOCATIONS IMPACTED INCLUDE...
HENDERSON...GREEN VALLEY...SAM BOYD STADIUM...EAST LAS VEGAS...UNLV
AND MCCARRAN INTERNATIONAL AIRPORT.

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.

&&

LAT...LON 3611 11521 3610 11492 3592 11492 3594 11513

$$

MORGAN
144 
WGUS75 KVEF 131652
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
952 AM PDT TUE SEP 13 2011

NVC003-131702-
/O.EXP.KVEF.FF.W.0087.000000T0000Z-110913T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
952 AM PDT TUE SEP 13 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 1000 AM PDT FOR CENTRAL
CLARK COUNTY...

AT 950 AM PDT...RADAR INDICATED THAT RAIN HAD ENDED IN HENDERSON. NO 
SIGNIFICANT REPORTS OF FLOODING HAVE BEEN RECEIVED SINCE 915 AM...SO 
THE FLASH FLOOD WARNING WILL BE ALLOWED TO EXPIRE AT 10 AM.

LAT...LON 3611 11521 3610 11492 3592 11492 3594 11513

$$

MORGAN

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 13, 3:31 AM PDTAreal Flood AdvisoryVEFClark119 min
Sep 13, 3:36 AM PDTFlash Flood WatchVEFClark15 hr
Sep 13, 5:46 AM PDTAreal Flood AdvisoryVEFClark119 min
Sep 13, 6:31 AM PDTFlash Flood WarningVEFClark86 min
Sep 13, 7:42 AM PDTFlash Flood WarningVEFClark2 hr
Sep 13, 8:23 AM PDTFlash Flood WarningVEFClark112 min

Nearby

Flash 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.