Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 1, NWS Sacramento, CA

October 24, 2021Lassen County, Plumas County, California

NWS Sacramento, CA issued this flash flood warning at Oct 24, 2021, 5:19 AM PDT for Lassen County, Plumas County, California. It was in force for 22 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: Oct 24, 2021, 5:19 AM PDT (12:19 UTC)
Expired: Oct 25, 2021, 3:00 AM PDT
In force: 22 hr
Issued by: NWS Sacramento, CA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Lassen County, CA, Plumas County, CA

The radar

The Beale AFB radar (KBBX), 93 km from the middle of the area, began a volume at 12:21 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

Medford/Jackson, OR (KMFR), launched 12:00Z, 0.3 hours before the alert went out and 266 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1356 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 203 m²/s²
0-3 km storm-relative helicity: 798 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

221 
WGUS56 KSTO 241219
FFWSTO
CAC035-063-251000-
/O.NEW.KSTO.FF.W.0001.211024T1219Z-211025T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sacramento CA
519 AM PDT Sun Oct 24 2021

The National Weather Service in Sacramento has issued a

* Flash Flood Warning for...
  The Dixie burn scar in...
  Southwestern Lassen County in northern California...
  Northwestern Plumas County in northern California...

* Until 300 AM PDT Monday.

* At 519 AM PDT, Doppler radar and automated rain gauges indicated 
  heavy rain moving towards the Dixie Burn Scar. Flash flooding is 
  expected to begin within the next several hours.

Excessive rainfall over the burn scar will result in debris flows. 
The debris flow can consist of rock, mud, vegetation and other loose 
materials.

  HAZARD...Life threatening flash flooding. Increasing rain rates
           over the next several hours will produce flash
           flooding in and around the Dixie Burn Scar.

  SOURCE...Radar and automated gauges.

  IMPACT...Life threatening flash flooding of areas in and around
           the Dixie Burn Scar.

* Some locations that will experience flash flooding include...
  Chester, Almanor, Prattville, Lake Almanor West, Lake Almanor 
  Country Club, Canyondam, East Shore, Caribou, Seneca, Belden, 
  Twain, Paxton, Indian Falls, Bald Eagle Mountain, Tobin, Crescent 
  Mills, Storrie, Keddie and Greenville.

Stretches of Highway 36, Highway 70, and Highway 89 in and around 
the Dixie Burn Scar.

This includes the following streams and drainages...
  Mill Creek, Canyon Creek, West Sulphur Creek, North Fork Feather 
  River, Deer Creek, Willow Creek and Butte Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause 
extensive and severe flash flooding of creeks...streams...and 
ditches in the Dixie Burn Scar. 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.

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry areas is likely. The heavy rains will 
likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

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

&&

LAT...LON 4015 12144 4035 12133 4035 12147 4044 12150
      4045 12133 4078 12132 4059 12132 4043 12106
      4031 12106 4030 12125 4026 12124 4020 12089
      4000 12079 4002 12099 3986 12140 4008 12137

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

$$

Rowe

3 follow-up statements

493 
WGUS76 KSTO 241439
FFSSTO

Flash Flood Statement
National Weather Service Sacramento CA
739 AM PDT Sun Oct 24 2021

CAC035-063-251000-
/O.CON.KSTO.FF.W.0001.000000T0000Z-211025T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lassen CA-Plumas CA-
739 AM PDT Sun Oct 24 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 3 AM PDT MONDAY FOR 
SOUTHWESTERN LASSEN AND NORTHWESTERN PLUMAS COUNTIES...

At 739 AM PDT, CalTrans reported multiple slides and debris flows in 
and around the Dixie Burn scar especially impacting Highway 70. 
Flash flooding is already occurring.

Excessive rainfall over the burn scar will result in debris flows. 
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 Dixie Burn Scar.

SOURCE...CalTrans reported.

IMPACT...Life threatening flash flooding of areas in and around
         the Dixie Burn Scar.

Some locations that will experience flash flooding include...
  Chester, Almanor, Prattville, Lake Almanor West, Lake Almanor 
  Country Club, Canyondam, East Shore, Caribou, Seneca, Belden, 
  Twain, Paxton, Indian Falls, Bald Eagle Mountain, Tobin, Crescent 
  Mills, Storrie, Keddie and Greenville.

Stretches of Highway 36, Highway 70, and Highway 89 in and around 
the Dixie Burn Scar.

This includes the following streams and drainages...
  Mill Creek, Canyon Creek, West Sulphur Creek, North Fork Feather 
  River, Deer Creek, Willow Creek and Butte Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause 
extensive and severe flash flooding of creeks...streams...and 
ditches in the Dixie Burn Scar. 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.

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry areas is likely. The heavy rains will 
likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

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

Move to higher ground now. Act quickly to protect your life.

&&

LAT...LON 4015 12144 4035 12133 4035 12147 4044 12150
      4045 12133 4078 12132 4059 12132 4043 12106
      4031 12106 4030 12125 4026 12124 4020 12089
      4000 12079 4002 12099 3986 12140 4008 12137

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

$$

CM

401 
WGUS76 KSTO 242231
FFSSTO

Flash Flood Statement
National Weather Service Sacramento CA
331 PM PDT Sun Oct 24 2021

CAC035-063-251000-
/O.CON.KSTO.FF.W.0001.000000T0000Z-211025T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lassen CA-Plumas CA-
331 PM PDT Sun Oct 24 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 3 AM PDT MONDAY FOR 
SOUTHWESTERN LASSEN AND NORTHWESTERN PLUMAS COUNTIES...

At 331 PM PDT, Areas of heavy rain continue over the Dixie Burn Scar 
and there have been reports of debris flows in and around the burn 
scar.

Continued rainfall over the burn scar could result in additional 
debris flows.
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 Dixie Burn Scar.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of areas in and around
         the Dixie Burn Scar.

Some locations that will experience flash flooding include...
  Chester, Almanor, Prattville, Lake Almanor West, Lake Almanor 
  Country Club, Canyondam, East Shore, Caribou, Seneca, Belden, 
  Twain, Paxton, Indian Falls, Bald Eagle Mountain, Tobin, Crescent 
  Mills, Storrie, Keddie and Greenville.

Stretches of Highway 36, Highway 70, and Highway 89 in and around 
the Dixie Burn Scar.

This includes the following streams and drainages...
  Mill Creek, Canyon Creek, West Sulphur Creek, North Fork Feather 
  River, Deer Creek, Willow Creek and Butte Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause 
extensive and severe flash flooding of creeks...streams...and 
ditches in the Dixie Burn Scar. 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.

Move away from recently burned areas. Life-threatening flooding of 
creeks, roads and normally dry areas is likely. The heavy rains will 
likely trigger rockslides, mudslides and debris flows in steep 
terrain, especially in and around these areas.

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

&&

LAT...LON 4015 12144 4035 12133 4035 12147 4044 12150
      4045 12133 4078 12132 4059 12132 4043 12106
      4031 12106 4030 12125 4026 12124 4020 12089
      4000 12079 4002 12099 3986 12140 4008 12137

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

$$

CM

808 
WGUS76 KSTO 250957
FFSSTO

Flash Flood Statement
National Weather Service Sacramento CA
257 AM PDT Mon Oct 25 2021

CAC035-063-251007-
/O.EXP.KSTO.FF.W.0001.000000T0000Z-211025T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lassen CA-Plumas CA-
257 AM PDT Mon Oct 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 3 AM PDT EARLY THIS MORNING 
FOR SOUTHWESTERN LASSEN AND NORTHWESTERN PLUMAS COUNTIES...

The heavy rain has ended over the western portions of the Dixie Fire 
burn scar. Flash flooding is no longer expected to pose an immediate 
threat. Minor debris flows will still be possible early this 
morning. Please continue to heed remaining road closures.

A Flash Flood Watch remains in effect until 500 AM PDT for a portion 
of northern California.

LAT...LON 4015 12144 4035 12133 4035 12147 4044 12150
      4045 12133 4078 12132 4059 12132 4043 12106
      4031 12106 4030 12125 4026 12124 4020 12089
      4000 12079 4002 12099 3986 12140 4008 12137

$$

DFR

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 24, 7:47 AM PDT	Flash Flood Warning Considerable damage threat	STO	El Dorado	25 hr
Oct 24, 9:52 AM PDT	Areal Flood Advisory	STO	Amador, Butte, Calaveras, Colusa, El Dorado, Glenn and 12 more	40 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.