Alert archive / Nevada / Flash Flood Warnings in 2012

Flash Flood Warning 203, NWS Las Vegas, NV

September 11, 2012Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Sep 11, 2012, 2:08 PM PDT for Clark County, Nevada. It was in force for 93 min. 13 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 11, 2012, 2:08 PM PDT (21:08 UTC)
Expired: Sep 11, 2012, 3:41 PM PDT
In force: 93 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), 52 km from the middle of the area, began a volume at 21:09 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

Time	Report	Where	Remark
Sep 11, 2:13 PM PDT	FLASH FLOOD	3 S Las Vegas, NV	REPORT OF 10 TO 12 INCHES OF WATER MOVING ACROSS DESERT INN ROAD NEAR MARYLAND.
Sep 11, 2:13 PM PDT	FLASH FLOOD	3 Sse Las Vegas Nellis, NV	SKYWARN RADIO REPORTS THAT THE INTERSECTION OF LAKE MEAD AND MT. HOOD IS IMPASSABLE DUE TO WATER MOVING ACROSS ROAD.
Sep 11, 2:13 PM PDT	FLASH FLOOD	Las Vegas, NV	REPORT OF 10 TO 12 INCHES OF WATER MOVING ACROSS DESERT INN ROAD BETWEEN J.W. BROWN ROAD AND MARYLAND.
Sep 11, 2:30 PM PDT	HEAVY RAIN 0.8	Las Vegas, NV	OVER 13000 NV ENERGY CUSTOMERS LOST POWER THROUGHOUT THE LAS VEGAS VALLEY...MOST IN NORTH LAS VEGAS.
Sep 11, 2:33 PM PDT	FLASH FLOOD	Las Vegas, NV	NWS EMPLOYEE REPORTS LARGE AMOUNT OF WATER MOVING ACROSS ARROYO GRANDE BETWEEN HORIZON RIDGE PARKWAY AND 215. WATER ALSO FLOWING ACROSS HORIZON RIDGE NEAR THE POST OFFICE.
Sep 11, 2:33 PM PDT	HEAVY RAIN 0	Las Vegas, NV	REPORT OF 2 FEET OF WATER AT THE INTERSECTION OF LAMB AND BONAZA.
Sep 11, 2:33 PM PDT	HEAVY RAIN 0.5	4 E Las Vegas, NV	REPORT OF 2 FEET OF WATER AT THE INTERSECTION OF LAMB AND BONAZA.
Sep 11, 3:00 PM PDT	FLASH FLOOD	5 Nw Green Valley, NV	10 BUSINESSES SUSTAINED SIGNIFICANT FLOOD DAMAGE IN THE PROMENADE SHOPPING CENTER ON MARYLAND PARKWAY NEAR UNLV. MUD WAS HALFWAY UP THE WALLS OF BUSINESSES. SOME BUSINESSES REPORTED COMPLETE DAMAGE TO FURNITURE AND EQUIPMENT. THE EVENT TIME IS AN ESTIMATE.
Sep 11, 3:00 PM PDT	FLASH FLOOD	6 Ese Las Vegas, NV	CLARK COUNTY FIREFIGHTERS RESCUED AT LEAST 50 PEOPLE FROM THEIR VEHICLES IN THE LAS VEGAS VALLEY WITH A TOTAL OF 40 SWIFTWATER RESCUE CALLS. 15 PEOPLE WERE RESCUED NEAR THE INTERSECTION OF SAHARA AND SLOAN WITH ONE RESCUE DONE BY HELICOPTER.
Sep 11, 3:00 PM PDT	HEAVY RAIN 1	1 Ese Las Vegas, NV	HEAVY RAIN CAUSED THE ROOF TO CAVE IN AT A BUSINESS NEAR BRUCE AND FREMONT STREETS.
Sep 11, 3:05 PM PDT	FLASH FLOOD	3 Wsw Las Vegas, NV	UP TO 3 INCHES OF WATER INSIDE HYDE PARK MIDDLE SCHOOL DUE TO FLASH FLOODING
Sep 11, 3:05 PM PDT	FLASH FLOOD	5 Nw Green Valley, NV	UP TO AN INCH OF WATER INSIDE THE TBE BUILDING ON THE CAMPUS OF UNLV DUE TO FLASH FLOODING.
Sep 11, 3:50 PM PDT	FLASH FLOOD	5 Ese Las Vegas, NV	AT LEAST 45 HOMES ON AND NEAR WALTON HEATH AVENUE WERE FLOODED BY 4 TO 5 FEET OF WATER. A NUMBER OF VEHICLES WERE FLOODED AND SOME WERE FLOATED 300 TO 400 FEET AWAY. 3 DOGS DIED AFTER THEY DROWNED IN THE FLOODWATERS. SEVERAL CONDOS ALSO FLOODED IN ANOTHER AREA

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, 9.1 hours before the alert went out and 49 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: 2 J/kg
Mixed-layer CIN: -171 J/kg
Mixed-layer LCL: 1725 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 37 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.

702 
WGUS55 KVEF 112108
FFWVEF
NVC003-112300-
/O.NEW.KVEF.FF.W.0203.120911T2108Z-120911T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
208 PM PDT TUE SEP 11 2012

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

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

* UNTIL 400 PM PDT.

* AT 156 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN FROM A THUNDERSTORM EXTENDING FROM THE NORTH       
  CENTRAL TO SOUTHCENTRAL VALLEY AND ACROSS THE EAST SIDE OF THE     
  VALLEY. THE STORM WAS MOVING EAST AT 10 MPH.

* LOCATIONS IMPACTED INCLUDE...
  NORTH CENTRAL TO SOUTHCENTRAL LAS VEGAS...EASTERN LAS VEGAS...     
  NELLIS AIR FORCE BASE.

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 3629 11487 3611 11486 3610 11517 3595 11516
      3601 11530 3627 11525

$$

JS

2 follow-up statements

226 
WGUS75 KVEF 112200
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
300 PM PDT TUE SEP 11 2012

NVC003-112300-
/O.CON.KVEF.FF.W.0203.000000T0000Z-120911T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
300 PM PDT TUE SEP 11 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM PDT FOR
CENTRAL CLARK COUNTY...

AT 257 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED THE 
HEAVIEST RAIN MOVING AWAY FROM THE NORTHERN AND WESTERN PORTIONS OF 
THE LAS VEGAS VALLEY. HOWEVER...FLASH FLOODING WAS ONGOING IN 
SEVERAL AREAS OF THE VALLEY...SO THE FLASH FLOOD WARNING REMAINS IN 
EFFECT UNTIL 4 PM.

LOCATIONS IMPACTED INCLUDE...
LAS VEGAS.

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 3629 11487 3611 11486 3610 11517 3595 11516
      3601 11530 3627 11525

$$

MORGAN

010 
WGUS75 KVEF 112241
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
341 PM PDT TUE SEP 11 2012

NVC003-112251-
/O.CAN.KVEF.FF.W.0203.000000T0000Z-120911T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
341 PM PDT TUE SEP 11 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL CLARK
COUNTY...

THE FLASH FLOOD WARNING FOR THE NORTHERN AND WESTERN LAS VEGAS 
VALLEY HAS BEEN REPLACED BY A NEW FLASH FLOOD WARNING VALID UNTIL 
545 PM.

LAT...LON 3629 11487 3611 11486 3610 11517 3595 11516
      3601 11530 3627 11525

$$

MORGAN

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 11, 3:24 AM PDT	Flash Flood Warning	VEF	Clark	111 min
Sep 11, 4:52 AM PDT	Flash Flood Warning	VEF	Nye	113 min
Sep 11, 8:28 AM PDT	Areal Flood Advisory	VEF	Lincoln	3 hr
Sep 11, 11:33 AM PDT	Areal Flood Advisory	VEF	Clark	3 hr
Sep 11, 12:32 PM PDT	Flash Flood Warning	VEF	Clark	88 min
Sep 11, 1:44 PM PDT	Areal Flood Advisory	VEF	Clark	27 min
Sep 11, 1:51 PM PDT	Flash Flood Warning	VEF	Clark	114 min
Sep 11, 2:16 PM PDT	Severe Thunderstorm Warning	VEF	Clark	44 min
Sep 11, 2:18 PM PDT	Flash Flood Warning	VEF	Clark	4 hr
Sep 11, 3:39 PM PDT	Flash Flood Warning	VEF	Clark	2 hr
Sep 11, 4:02 PM PDT	Flash Flood Warning	VEF	Clark	118 min

Nearby

Flash Flood Warnings in Nevada, 2012 Every flash flood warning in 2012

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.