Alert archive / California / Flash Flood Warnings in 2017

Flash Flood Warning 84, NWS Las Vegas, NV

August 10, 2017San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 10, 2017, 4:47 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 10, 2017, 4:47 PM PDT (23:47 UTC)
Expired
Aug 10, 2017, 7:45 PM PDT
In force
3 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

The radar

The Las Vegas radar (KESX), 139 km from the middle of the area, began a volume at 23:50 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 10, 5:16 PM PDTFLASH FLOOD11 W Rice, CACALIFORNIA HIGHWAY PATROL REPORTED WATER FLOWING OVER HIGHWAY 62, WITH ROAD BEGINNING TO WASH AWAY NEAR MILE MARKER 93.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Yuma Prvg Ground, AZ (K1Y7), launched 12:00Z, 11.8 hours before the alert went out and 220 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, Yuma Prvg Ground, AZ at 12:00Z on 2017-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 370 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, Yuma Prvg Ground, AZ at 12:00Z on 2017-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -54 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
370 J/kg
Mixed-layer CIN
-455 J/kg
Mixed-layer LCL
2418 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-54 m²/s²
0-3 km storm-relative helicity
-18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

817 
WGUS55 KVEF 102347
FFWVEF
CAC071-110245-
/O.NEW.KVEF.FF.W.0084.170810T2347Z-170811T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
447 PM PDT THU AUG 10 2017

The National Weather Service in Las Vegas has issued a

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

* Until 745 PM PDT

* At 444 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across portions of southeast San Bernardino County. 
  Flash flooding is expected along Highway 95 between Vidal Junction 
  and Needles and between Vidal Junction west to mile marker 90 on 
  Highway 62. Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Highway 95 At Mile Marker 29, Parker Dam, Needles, Three Dunes
  Campground, Black Meadow Landing Campground, Earp, Vidal Junction,
  Big River and Highway 95 And I-40.

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 3408 11535 3409 11535 3492 11505 3499 11463
      3487 11464 3471 11447 3459 11444 3452 11438
      3446 11439 3436 11419 3426 11413 3408 11444

$$

ASG
2 follow-up statements
005 
WGUS75 KVEF 110034
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
534 PM PDT THU AUG 10 2017

CAC071-110245-
/O.CON.KVEF.FF.W.0084.000000T0000Z-170811T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
534 PM PDT THU AUG 10 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM PDT FOR
SOUTHEASTERN SAN BERNARDINO COUNTY...

At 531 PM PDT, local law enforcement reported flash flooding near 
mile marker 93 along Highway 62 west of Vidal Junction. Additional 
heavy rain due to thunderstorms will likely continue through 730 pm. 
Additional flash flooding is likely along Highway 62 and along 
Highway 95 between Vidal Junction and Needles. 

Some locations that will experience flooding include...
Highway 95 At Mile Marker 29, Parker Dam, Needles, Three Dunes
Campground, Black Meadow Landing Campground, Earp, Vidal Junction,
Big River and Highway 95 And I-40.

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 3408 11535 3409 11535 3492 11505 3499 11463
      3487 11464 3471 11447 3459 11444 3452 11438
      3446 11439 3436 11419 3426 11413 3408 11444

$$

ASG
010 
WGUS75 KVEF 110242
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
742 PM PDT THU AUG 10 2017

CAC071-110251-
/O.EXP.KVEF.FF.W.0084.000000T0000Z-170811T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
742 PM PDT THU AUG 10 2017

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN SAN BERNARDINO COUNTY
WILL EXPIRE AT 745 PM PDT...

The heavy rain has ended and flooding is no longer expected to pose 
a threat. Standing water may still be present along Highway 62 
between Vidal Juction and Mile Marker 90 and along Highway 95 
between Vidal Juction and Needles. Please continue to heed any 
remaining road closures.

LAT...LON 3408 11535 3409 11535 3492 11505 3499 11463
      3487 11464 3471 11447 3459 11444 3452 11438
      3446 11439 3436 11419 3426 11413 3408 11444

$$

ASG

Nearby

Flash Flood Warnings in California, 2017Every flash flood warning in 2017

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.