Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 23, NWS San Diego, CA

December 14, 2021Riverside County, San Bernardino County, California

NWS San Diego, CA issued this flash flood warning at Dec 14, 2021, 1:27 PM PST for Riverside County, San Bernardino County, California. It was in force for 108 min. 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: Dec 14, 2021, 1:27 PM PST (21:27 UTC)
Expired: Dec 14, 2021, 3:15 PM PST
In force: 108 min
Issued by: NWS San Diego, CA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Riverside County, CA, San Bernardino County, CA

What was reported inside it

Time	Report	Where	Remark
Dec 14, 2:00 PM PST	FLASH FLOOD	3 N Beaumont, CA	VINELAND AND NOBLE IN BEAUMONT AREA. 10+ FOOT LONG TREE BRANCHES/TRUNKS WASHING THROUGH AS WELL AND ROCKS LARGER THAN A FOOT ROUND WASHING THROUGH. WATER FLOWING OVER 1 FOOT OVER CROSSING. WEBCAMERAS SHOWING DARK WATER FLOW AND DEBRIS. APPLE FIRE SCAR. RAINFAL

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

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 9.5 hours before the alert went out and 137 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: 1 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 666 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 200 m²/s²
0-3 km storm-relative helicity: 172 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

758 
WGUS56 KSGX 142127
FFWSGX
CAC065-071-142315-
/O.NEW.KSGX.FF.W.0023.211214T2127Z-211214T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Diego CA
127 PM PST Tue Dec 14 2021

The National Weather Service in San Diego has issued a

* Flash Flood Warning for...
  The El Dorado and Apple burn scar in...
  Riverside County in southern California...
  San Bernardino County in southern California...

* Until 315 PM PST.

* At 127 PM PST, Doppler radar and automated rain gauges indicated 
  heavy rain falling over the El Dorado and Apple Burn Scar. The 
  expected rainfall rate is 0.5 to 1 inch in 1 hour. Flash flooding 
  is ongoing or expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Birch Creek, Potato Canyon, Little San Gorgonio 
Creek, Forsee Creek, Glen Martin Creek, Oak Glen Creek, Wilson 
Creek, Mountain Home Creek, San Gorgonio River, Portrero Creek, Mias 
Canyon, Corral Canyon, Millard Canyon, and the south fork of the 
Whitewater River. The debris flow can consist of rock, mud, 
vegetation and other loose materials.

  HAZARD...Life threatening flash flooding. Heavy rain producing
           flash flooding in and around the El Dorado and Apple
           Burn Scar.

  SOURCE...Radar and automated gauges.

  IMPACT...Life threatening flash flooding of areas in and around
           the El Dorado and Apple Burn Scar.

* Some locations that will experience flash flooding include...
  Yucaipa, Forest Falls, southern Mount San Gorgonio, Beaumont, 
  Banning, Hwy 38 Between Yucaipa And Onyx Summit, Mountain Home 
  Village, Calimesa, Cherry Valley and Morongo Indian Reservation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall may cause 
extensive and severe flash flooding of creeks, streams, and ditches 
in the El Dorado and Apple Burn Scars. Severe debris flows can also 
be anticipated across roads. Roads and driveways may be washed away 
in places. If you encounter flood waters, climb to safety.

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

&&

LAT...LON 3401 11702 3405 11703 3411 11700 3409 11676
      3397 11679 3394 11686 3394 11697 3398 11702

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...0.5-1 INCH IN 1 HOUR

$$

Connolly

1 follow-up statement

945 
WGUS76 KSGX 142318
FFSSGX

Flash Flood Statement
National Weather Service San Diego CA
318 PM PST Tue Dec 14 2021

CAC065-071-142328-
/O.EXP.KSGX.FF.W.0023.000000T0000Z-211214T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Riverside CA-San Bernardino CA-
318 PM PST Tue Dec 14 2021

...FLASH FLOOD WARNING FOR THE EL DORADO AND APPLE BURN SCAR HAS 
EXPIRED FOR RIVERSIDE AND SAN BERNARDINO COUNTIES...

Flood waters and mud flows have started to recede. The heavy 
rainfall rates of 0.3 to 0.6 inch per hour have ended. Additional 
light to occasional moderate rainfall will continue with rates up to 
0.15 to 0.25 inches per hour. Snow levels have lowered to 5000 feet 
and will reach 4000 feet by 4 pm. Flooding is no longer expected to 
pose a threat. Please continue to heed remaining road closures and 
avoid flooded areas. Water and mud will continue to flow in channels 
and creeks in Noble and Mias Canyons. Highway 38 closed due to rocks 
and debris on the roadway.

A Flood Watch remains in effect until 900 PM PST for a portion of 
Southern California.

LAT...LON 3401 11702 3405 11703 3411 11700 3409 11676
      3397 11679 3394 11686 3394 11697 3398 11702

$$

Tardy

The office that day

Everything else NWS San Diego, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 14, 7:34 AM PST	Areal Flood Advisory	SGX	Orange, Riverside	4 hr
Dec 14, 8:09 AM PST	Areal Flood Advisory	SGX	Orange	4 hr
Dec 14, 9:23 AM PST	Areal Flood Advisory	SGX	San Bernardino	4 hr
Dec 14, 10:36 AM PST	Flash Flood Warning Considerable damage threat	SGX	Orange	3 hr
Dec 14, 11:01 AM PST	Flash Flood Warning Considerable damage threat	SGX	Orange	89 min
Dec 14, 11:46 AM PST	Areal Flood Advisory	SGX	San Diego	3 hr
Dec 14, 1:00 PM PST	Areal Flood Advisory	SGX	Riverside, San Bernardino	3 hr
Dec 14, 1:15 PM PST	Areal Flood Advisory	SGX	San Diego	3 hr

Nearby

Flash Flood Warnings in California, 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.