Alert archive / Nevada / Flash Flood Warnings in 2011

Flash Flood Warning 104, NWS Las Vegas, NV

October 4, 2011Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Oct 4, 2011, 11:58 AM PDT for Clark County, Nevada. It was in force for 2 hr. 5 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
Oct 4, 2011, 11:58 AM PDT (18:58 UTC)
Expired
Oct 4, 2011, 2:00 PM PDT
In force
2 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County Clark County, NV

The radar

The Las Vegas radar (KESX), 49 km from the middle of the area, began a volume at 18:59 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
Oct 4, 12:00 PM PDTFLASH FLOODNe East Las Vegas, NVSEVERAL AREA RAIN GAUGES REPORTED AROUND AN INCH OF RAIN BETWEEN 1130AM AND 1230PM IN THE VICINITY OF JIMMY DURANTE BLVD AND TROPICANA AVE. SEVERAL CARS BECAME STRANDED IN THE INTERSECTION DUE TO THE HIGH WATER AND A CLARK COUNTY SWIFT WATER RESCUE TEAM HELPED
Oct 4, 12:07 PM PDTHEAVY RAIN 0.55 Ese Las Vegas, NVONE HALF OF AN INCH OF RAIN MEASURED IN 15 MINUTES AT NELLIS AND VEGAS VALLEY. RUNOFF CURB HIGH.
Oct 4, 12:08 PM PDTHEAVY RAIN 0.55 E Las Vegas, NVONE HALF INCH OF RAIN IN 20 MINUTES AND PEA SIZE HAIL.
Oct 4, 12:23 PM PDTFLASH FLOOD2 Ene Green Valley, NVA TRAINED SPOTTER BETWEEN RUSSEL AND SUNSET ON STEPHANIE REPORTED WATER FLOWING OVER AND ABOVE THE CURB AND COVERING THREE QUATERS OF THE ROADWAY.
Oct 4, 12:45 PM PDTFLASH FLOOD3 N Green Valley, NVA TRAINED SPOTTER ON MARKS STREET REPORTED WATER AS DEEP AS 18 INCHES ON THE ROADWAY BETWEEN AMERICAN PACIFIC AND WARM SPRINGS.

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, 7.0 hours before the alert went out and 52 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 2011-10-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 722 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 2011-10-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 32 square meters per square second.193958Sfc1 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
722 J/kg
Mixed-layer CIN
-34 J/kg
Mixed-layer LCL
903 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
86 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

061 
WGUS55 KVEF 041858
FFWVEF
NVC003-042100-
/O.NEW.KVEF.FF.W.0104.111004T1858Z-111004T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
1158 AM PDT TUE OCT 4 2011

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

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

* UNTIL 200 PM PDT.

* AT 1150 AM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR SAM BOYD STADIUM...OR NEAR
  HENDERSON...MOVING NORTH AT 10 MPH.

* LOCATIONS IMPACTED INCLUDE...
  SAM BOYD STADIUM...EAST LAS VEGAS...HIGHWAY 93...AND BOULDER
  HIGHWAY.

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 BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3620 11512 3620 11490 3601 11499 3600 11512

$$
SC
4 follow-up statements
887 
WGUS75 KVEF 041919
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1219 PM PDT TUE OCT 4 2011

NVC003-042100-
/O.CON.KVEF.FF.W.0104.000000T0000Z-111004T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
1219 PM PDT TUE OCT 4 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 200 PM PDT FOR
CENTRAL CLARK COUNTY...

AT 1208 PM PDT...TRAINED WEATHER SPOTTERS REPORTED A THUNDERSTORM 
PRODUCING VERY HEAVY RAIN. MULTIPLE RAIN GAUGES IN THE AREA HAVE 
OBSERVED BETWEEN ONE HALF AND THREE QUARTERS OF AN INCH OF RAIN 
SINCE 1145 AM. THE INITIAL STORM WAS LOCATED NEAR EAST LAS 
VEGAS...OR 7 MILES NORTH OF HENDERSON...MOVING NORTH AT 15 MPH. A 
SECOND STORM HAS DEVELOPED TO THE SOUTH AS WAS LOCATED NEAR THE 
INTERSECTION OF HIGHWAY 93 AND 215. 

LOCATIONS IMPACTED INCLUDE...
HENDERSON...SAMS TOWN...AND BOULDER HIGHWAY.

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 BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3620 11512 3620 11490 3601 11499 3600 11512

$$

SC
915 
WGUS75 KVEF 041940
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1240 PM PDT TUE OCT 4 2011

NVC003-042100-
/O.CON.KVEF.FF.W.0104.000000T0000Z-111004T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
1240 PM PDT TUE OCT 4 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 200 PM PDT FOR
CENTRAL CLARK COUNTY...

AT 1223 PM PDT...TRAINED WEATHER SPOTTERS REPORTED FLASH FLOODING 
ALONG STEPHANIE STREET BETWEEN SUNSET AND RUSSELL ROAD. AT 1235 PM 
THIS STORM WAS LOCATED NEAR SAMS TOWN...MOVING NORTH AT 15 MPH. 
INTENSE RAINFALL RATES...ONE HALF INCH OF RAIN IN 10 TO 15 MINUTES 
HAVE BEEN OBSERVED WITH THESE STORMS. SEVERAL RAIN GAUGES HAVE 
RECORDED THREE QUARTERS TO NEAR ONE INCH OF RAINFALL SINCE 1145 AM.

LOCATIONS IMPACTED INCLUDE...
HENDERSON...SAMS TOWN...AND BOULDER HIGHWAY.

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 BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3620 11512 3620 11490 3601 11499 3600 11512

$$

SC
411 
WGUS75 KVEF 042000
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
100 PM PDT TUE OCT 4 2011

NVC003-042100-
/O.CON.KVEF.FF.W.0104.000000T0000Z-111004T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
100 PM PDT TUE OCT 4 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 200 PM PDT FOR
CENTRAL CLARK COUNTY...

AT 1248 PM PDT...TRAINED WEATHER SPOTTERS REPORTED FLASH FLOODING 
ALONG MARKS STREET BETWEEN AMERICAN PACIFIC AND WARM SPRINGS AS WELL 
AS ALONG STEPHANIE BETWEEN RUSSEL AND SUNSET. A THUNDERSTORM 
PRODUCING VERY HEAVY RAIN WAS LOCATED 8 MILES NORTH OF SAMS 
TOWN...OR 7 MILES EAST OF DOWNTOWN LAS VEGAS...MOVING NORTH AT 15 
MPH. THE HEAVY RAIN WILL BE ENDING BY 115 PM...HOWEVER FLASH 
FLOODING AND RUNOFF IS EXPECTED TO PERSIST THROUGH 200 PM.

LOCATIONS IMPACTED INCLUDE...
HENDERSON...GALLERIA MALL...SAMS TOWN AND BOULDER HIGHWAY

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 BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3620 11512 3620 11490 3601 11499 3600 11512

$$

SC
442 
WGUS75 KVEF 042054
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
154 PM PDT TUE OCT 4 2011

NVC003-042100-
/O.EXP.KVEF.FF.W.0104.000000T0000Z-111004T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
154 PM PDT TUE OCT 4 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 200 PM PDT FOR CENTRAL
CLARK COUNTY...

THE HEAVY RAIN ENDED SHORTLY AFTER 100 PM OVER THE EASTERN PORTIONS 
OF THE LAS VEGAS VALLEY. ALTHOUGH RUNOFF MAY CONTINUE TO PRODUCE 
MINOR FLOODING THE THREAT OF ADDITIONAL FLASH FLOODING HAS ENDED AND 
THEREFORE THE FLASH FLOOD WARNING FOR CENTRAL CLARK COUNTY WILL BE 
ALLOWED TO EXPIRE AT 200 PM. 

LAT...LON 3620 11512 3620 11490 3601 11499 3600 11512

$$

SC

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 3, 6:45 PM PDTAreal Flood AdvisoryVEFClark46 min
Oct 3, 11:12 PM PDTAreal Flood AdvisoryVEFClark2 hr
Oct 4, 4:05 AM PDTFlash Flood WatchVEFClark, Lincoln15 hr
Oct 4, 1:31 PM PDTFlash Flood WarningVEFClark87 min
Oct 4, 2:14 PM PDTWind AdvisoryVEFClark, Lincoln, Nye36 hr

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.