Alert archive / Nevada / Flash Flood Warnings in 2021

Flash Flood Warning 8, NWS Las Vegas, NV

July 12, 2021Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Jul 12, 2021, 10:28 PM PDT for Clark County, Nevada. It was in force for 3 hr. 1 report 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 12, 2021, 10:28 PM PDT (05:28 UTC)
Expired: Jul 13, 2021, 1:30 AM PDT
In force: 3 hr
Issued by: NWS Las Vegas, NV
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Clark County, NV

The radar

The Las Vegas radar (KESX), 70 km from the middle of the area, began a volume at 05:30 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
Jul 12, 11:45 PM PDT	FLASH FLOOD	1 Nne Callville Bay, NV	FEW FEET OF DEBRIS OVER CALLVILLE BAY ACCESS RD. DEBRIS DAMAGED HEADWALK FROM THE SHORE TO THE DOCKS, AS WELL AS THEIR SEWAGE LIFT STATION.

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 00:00Z, 5.5 hours before the alert went out and 77 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: 1416 J/kg
Mixed-layer CIN: -26 J/kg
Mixed-layer LCL: 3734 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: 87 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

317 
WGUS55 KVEF 130528
FFWVEF
NVC003-130830-
/O.NEW.KVEF.FF.W.0008.210713T0528Z-210713T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
1028 PM PDT Mon Jul 12 2021

The National Weather Service in Las Vegas has issued a

* Flash Flood Warning for...
  Northeastern Clark County in southern Nevada...

* Until 130 AM PDT.

* At 1028 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the area around Valley of Fire State Park and 
  areas south toward Lake Mead. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Valley Of Fire Highway, Valley of Fire State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3645 11482 3657 11464 3644 11441 3615 11449
      3618 11462 3613 11469 3611 11480 3626 11484

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

JA

3 follow-up statements

387 
WGUS75 KVEF 130639
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1139 PM PDT Mon Jul 12 2021

NVC003-130830-
/O.CON.KVEF.FF.W.0008.000000T0000Z-210713T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
1139 PM PDT Mon Jul 12 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 130 AM PDT TUESDAY 
FOR EASTERN CLARK COUNTY...

At 1139 PM PDT, Doppler radar indicated thunderstorms producing 
heavy rain across the Callville Bay and Boulder Basin area of Lake 
Mead. Between 1 and 1.5 inches of rain have likely fallen over the 
area extending from Callville Bay to the Valley of Fire Highway. 
Flash flooding is ongoing or expected to begin shortly.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  Valley Of Fire Highway, Callville Bay Campground and Callville Bay.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3645 11482 3657 11464 3644 11441 3615 11449
      3618 11462 3613 11469 3611 11480 3626 11484

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

JA

680 
WGUS75 KVEF 130743
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1243 AM PDT Tue Jul 13 2021

NVC003-130830-
/O.CON.KVEF.FF.W.0008.000000T0000Z-210713T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
1243 AM PDT Tue Jul 13 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 130 AM PDT EARLY THIS 
MORNING FOR NORTHEASTERN CLARK COUNTY...

At 1243 AM PDT, Doppler radar indicated thunderstorms had dissipated 
over the Boulder Basin of Lake Mead. Between 0.67 and 1.5 inches of 
rain fell over the area extending from Callville Bay to Valley of 
Fire Highway near I-15. Flash flooding will likely impact roads 
within the warning area until 130 AM

HAZARD...Life-threatening flash flooding.

SOURCE...Radar and automated gauges.

IMPACT...Life-threatening flash flooding of low-water crossings,
         normally dry washes and roads.

Some locations that will experience flash flooding include...
  Valley Of Fire Highway and Callville Bay.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3645 11482 3657 11464 3644 11441 3615 11449
      3618 11462 3613 11469 3611 11480 3626 11484

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

JA

472 
WGUS75 KVEF 130824
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
124 AM PDT Tue Jul 13 2021

NVC003-130834-
/O.EXP.KVEF.FF.W.0008.000000T0000Z-210713T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
124 AM PDT Tue Jul 13 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 130 AM PDT EARLY THIS MORNING 
FOR NORTHEASTERN CLARK COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3645 11482 3657 11464 3644 11441 3615 11449
      3618 11462 3613 11469 3611 11480 3626 11484

$$

Lericos

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 9:50 PM PDT	Severe Thunderstorm Warning	VEF	Clark	55 min
Jul 12, 10:44 PM PDT	Severe Thunderstorm Warning	VEF	Clark	46 min
Jul 12, 11:27 PM PDT	Severe Thunderstorm Warning	VEF	Clark	48 min
Jul 13, 4:19 PM PDT	Severe Thunderstorm Warning	VEF	Lincoln, Nye	56 min

Nearby

Flash Flood Warnings in Nevada, 2021 Every flash flood warning in 2021

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.