Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 68, NWS Las Vegas, NV

July 26, 2021San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Jul 26, 2021, 8:12 AM PDT for San Bernardino County, California. 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 26, 2021, 8:12 AM PDT (15:12 UTC)
Expired
Jul 26, 2021, 11:15 AM 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 nearest sounding before it

Las Vegas, NV (KVEF), launched 12:00Z, 3.2 hours before the alert went out and 155 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 2021-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 467 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 2021-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -37 square meters per square second.193958Sfc1 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
467 J/kg
Mixed-layer CIN
-144 J/kg
Mixed-layer LCL
1095 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
-37 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

231 
WGUS55 KVEF 261512
FFWVEF
CAC071-261815-
/O.NEW.KVEF.FF.W.0068.210726T1512Z-210726T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
812 AM PDT Mon Jul 26 2021

The National Weather Service in Las Vegas has issued a

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

* Until 1115 AM PDT.

* At 812 AM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain near Kelbaker Rd south of Kelso. Between 0.5 and 1 inch 
  of rain has fallen and up to an an additional inch is possible. 
  Flash flooding is ongoing or expected to begin shortly and roads 
  may become impassable.

  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...
  Kelso and Mitchell Caverns.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3519 11552 3514 11545 3508 11549 3505 11550
      3495 11548 3491 11546 3486 11545 3481 11547
      3478 11551 3475 11557 3475 11566 3478 11575
      3486 11581 3492 11582 3504 11578 3511 11573
      3515 11569 3518 11562 3520 11556

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

$$

CO
2 follow-up statements
712 
WGUS75 KVEF 261648
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
948 AM PDT Mon Jul 26 2021

CAC071-261815-
/O.CON.KVEF.FF.W.0068.000000T0000Z-210726T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
948 AM PDT Mon Jul 26 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 AM PDT THIS 
MORNING FOR SAN BERNARDINO COUNTY...

At 948 AM PDT, Thunderstorm activity has begun lifting northward 
however light to moderate rain and continued runoff is occuring. 
Area washes and drainages remain elevated and flooded roadways 
remain likely on Kelbaker road.

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...
  Kelso and Mitchell Caverns.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3519 11552 3514 11545 3508 11549 3505 11550
      3495 11548 3491 11546 3486 11545 3481 11547
      3478 11551 3475 11557 3475 11566 3478 11575
      3486 11581 3492 11582 3504 11578 3511 11573
      3515 11569 3518 11562 3520 11556

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

$$

CO
462 
WGUS75 KVEF 261808
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1108 AM PDT Mon Jul 26 2021

CAC071-261818-
/O.EXP.KVEF.FF.W.0068.000000T0000Z-210726T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
1108 AM PDT Mon Jul 26 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1115 AM PDT THIS MORNING FOR 
SAN BERNARDINO 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 1100 PM PDT Monday for 
portions of southeast California and southern Nevada.

LAT...LON 3519 11552 3514 11545 3508 11549 3505 11550
      3495 11548 3491 11546 3486 11545 3481 11547
      3478 11551 3475 11557 3475 11566 3478 11575
      3486 11581 3492 11582 3504 11578 3511 11573
      3515 11569 3518 11562 3520 11556

$$

CO

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 25, 6:59 PM PDTFlash Flood Warning Considerable damage threatVEFSan Bernardino3 hr
Jul 25, 9:55 PM PDTSevere Thunderstorm WarningVEFInyo, San Bernardino50 min
Jul 25, 11:13 PM PDTFlash Flood Warning Considerable damage threatVEFInyo, San Bernardino3 hr
Jul 26, 7:59 AM PDTAreal Flood AdvisoryVEFSan Bernardino3 hr
Jul 26, 9:26 AM PDTAreal Flood AdvisoryVEFSan Bernardino3 hr
Jul 26, 10:44 AM PDTFlash Flood Warning Considerable damage threatVEFInyo, San Bernardino3 hr
Jul 26, 11:36 AM PDTFlash Flood Warning Considerable damage threatVEFInyo, San Bernardino3 hr
Jul 26, 12:29 PM PDTFlash Flood Warning Considerable damage threatVEFInyo3 hr
Jul 26, 12:51 PM PDTFlash Flood Warning Considerable damage threatVEFInyo, San Bernardino3 hr
Jul 26, 1:12 PM PDTFlash Flood Warning Considerable damage threatVEFInyo4 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; the sounding from the Mesonet's radiosonde archive.