Alert archive / Nevada / Flash Flood Warnings in 2021

Flash Flood Warning 65, NWS Las Vegas, NV

July 25, 2021Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Jul 25, 2021, 8:09 PM PDT for Clark County, Nevada. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 25, 2021, 8:09 PM PDT (03:09 UTC)
Expired: Jul 25, 2021, 11:15 PM 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), 94 km from the middle of the area, began a volume at 03:11 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.

The nearest sounding before it

Las Vegas, NV (KVEF), launched 00:00Z, 3.2 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-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: 707 J/kg
Mixed-layer CIN: -44 J/kg
Mixed-layer LCL: 2729 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 81 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

847 
WGUS55 KVEF 260309
FFWVEF
NVC003-260615-
/O.NEW.KVEF.FF.W.0065.210726T0309Z-210726T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
809 PM PDT Sun Jul 25 2021

The National Weather Service in Las Vegas has issued a

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

* Until 1115 PM PDT.

* At 809 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across Valley of Fire State Park and 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...
  Moapa Town, Overton, Moapa Valley, Valley Of Fire, Logandale, 
  Overton Beach, Echo Bay Campground and Echo Bay.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3667 11502 3676 11465 3675 11461 3651 11423
      3629 11437 3629 11472 3637 11489 3652 11510

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

$$

CP

2 follow-up statements

989 
WGUS75 KVEF 260429
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
929 PM PDT Sun Jul 25 2021

NVC003-260615-
/O.CON.KVEF.FF.W.0065.000000T0000Z-210726T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
929 PM PDT Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM PDT THIS 
EVENING FOR NORTHEASTERN CLARK COUNTY...

At 929 PM PDT, Heavy rain has moved out of the warned area, but an 
inch and a half to 2 inches fell across Valley of Fire Highway and 
into the California Wash. 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...
  Moapa Town, Overton, Moapa Valley, Valley Of Fire, Logandale, 
  Overton Beach, Echo Bay Campground and Echo Bay.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3667 11502 3676 11465 3675 11461 3651 11423
      3629 11437 3629 11472 3637 11489 3652 11510

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

$$

CP

834 
WGUS75 KVEF 260609
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1109 PM PDT Sun Jul 25 2021

NVC003-260619-
/O.EXP.KVEF.FF.W.0065.000000T0000Z-210726T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
1109 PM PDT Sun Jul 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1115 PM PDT THIS EVENING 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.

A Flash Flood Watch remains in effect until 1200 AM PDT for portions 
of northwest Arizona, southeast California and southern Nevada.

LAT...LON 3667 11502 3676 11465 3675 11461 3651 11423
      3629 11437 3629 11472 3637 11489 3652 11510

$$

CP

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 25, 5:12 PM PDT	Dust Storm Warning	VEF	Clark	63 min
Jul 25, 5:37 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Lincoln	3 hr
Jul 25, 6:01 PM PDT	Severe Thunderstorm Warning	VEF	Clark	59 min
Jul 25, 6:06 PM PDT	Severe Thunderstorm Warning	VEF	Lincoln	39 min
Jul 25, 7:08 PM PDT	Severe Thunderstorm Warning	VEF	Clark	52 min
Jul 25, 7:57 PM PDT	Severe Thunderstorm Warning	VEF	Clark, Lincoln	63 min
Jul 25, 8:59 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Clark	3 hr
Jul 25, 8:59 PM PDT	Severe Thunderstorm Warning	VEF	Clark, Nye	61 min
Jul 25, 9:55 PM PDT	Severe Thunderstorm Warning	VEF	Clark, Nye	50 min
Jul 26, 10:20 AM PDT	Flash Flood Warning Considerable damage threat	VEF	Clark	3 hr
Jul 26, 10:44 AM PDT	Flash Flood Warning Considerable damage threat	VEF	Clark	3 hr
Jul 26, 11:32 AM PDT	Flash Flood Warning Considerable damage threat	VEF	Clark, Nye	4 hr
Jul 26, 12:29 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Nye	3 hr
Jul 26, 12:40 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Nye	3 hr
Jul 26, 1:28 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Lincoln	3 hr
Jul 26, 2:05 PM PDT	Severe Thunderstorm Warning	VEF	Lincoln	40 min
Jul 26, 4:30 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Lincoln	2 hr
Jul 26, 4:34 PM PDT	Severe Thunderstorm Warning	VEF	Lincoln	41 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.