Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 120, NWS Las Vegas, NV

August 30, 2021San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 30, 2021, 1:17 PM PDT for San Bernardino County, California. 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
Aug 30, 2021, 1:17 PM PDT (20:17 UTC)
Expired
Aug 30, 2021, 4:15 PM PDT
In force
3 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County San Bernardino County, CA

The radar

The Las Vegas radar (KESX), 48 km from the middle of the area, began a volume at 20:18 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
Aug 30, 1:30 PM PDTFLASH FLOOD5 W Nipton, CAREPORT OF FLASH FLOODING ON NIPTON ROAD EAST OF IVANPAH ROAD.

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, 8.3 hours before the alert went out and 103 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 2021-08-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 37 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 2021-08-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -27 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
37 J/kg
Mixed-layer CIN
-324 J/kg
Mixed-layer LCL
3297 m above ground
0-6 km bulk shear
2 kt
0-1 km storm-relative helicity
-27 m²/s²
0-3 km storm-relative helicity
39 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

876 
WGUS55 KVEF 302017
FFWVEF
CAC071-302315-
/O.NEW.KVEF.FF.W.0120.210830T2017Z-210830T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
117 PM PDT Mon Aug 30 2021

The National Weather Service in Las Vegas has issued a

* Flash Flood Warning for...
  San Bernardino County in southern California...

* Until 415 PM PDT.

* At 117 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain over Nipton Road just west of the Nevada state line. 
  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...
  Nipton and Nipton And Ivanpah Roads.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3547 11539 3548 11526 3546 11526 3545 11539

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

$$

CM
2 follow-up statements
290 
WGUS75 KVEF 302205
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
305 PM PDT Mon Aug 30 2021

CAC071-302315-
/O.CON.KVEF.FF.W.0120.000000T0000Z-210830T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
305 PM PDT Mon Aug 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM PDT THIS 
AFTERNOON FOR SAN BERNARDINO COUNTY...

At 305 PM PDT, California Highway Patrol reported vehicles stuck 
along Nipton Road near I-15. Nipton road will remain impassable due 
to flooding and debris through late afternoon.

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

SOURCE...Law enforcement reported.

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

Some locations that will experience flash flooding include...
  Nipton road.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3547 11539 3548 11526 3546 11526 3545 11539

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

JA
412 
WGUS75 KVEF 302310
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
410 PM PDT Mon Aug 30 2021

CAC071-302320-
/O.EXP.KVEF.FF.W.0120.000000T0000Z-210830T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
410 PM PDT Mon Aug 30 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 415 PM PDT THIS AFTERNOON FOR 
NIPTON ROAD IN SAN BERNARDINO COUNTY...

Flooding is no longer expected to pose a threat for Nipton Road in 
eastern San Bernardino county though residual debris may make the 
road impassible until crews can clear it off. Please continue to 
heed remaining road closures.

LAT...LON 3547 11539 3548 11526 3546 11526 3545 11539

$$

JA

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 29, 6:53 PM PDTFlash Flood Warning Considerable damage threatVEFSan Bernardino3 hr
Aug 30, 3:28 AM PDTFlash Flood WatchVEFSan Bernardino59 hr
Aug 30, 2:37 PM PDTFlash Flood Warning Considerable damage threatVEFSan Bernardino3 hr
Aug 30, 2:55 PM PDTFlash Flood Warning Considerable damage threatVEFSan Bernardino3 hr

Nearby

Flash Flood Warnings in California, 2021Every 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.