Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 2, NWS Sacramento, CA

October 24, 2021El Dorado County, California

NWS Sacramento, CA issued this flash flood warning at Oct 24, 2021, 7:47 AM PDT for El Dorado County, California. It was in force for 25 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, 7:47 AM PDT (14:47 UTC)
Expired: Oct 25, 2021, 9:00 AM PDT
In force: 25 hr
Issued by: NWS Sacramento, CA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County El Dorado County, CA

The radar

The Sacramento radar (KDAX), 119 km from the middle of the area, began a volume at 14:50 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.

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 2.8 hours before the alert went out and 196 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: 470 m above ground
0-6 km bulk shear: 76 kt
0-1 km storm-relative helicity: 503 m²/s²
0-3 km storm-relative helicity: 702 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

409 
WGUS56 KSTO 241447
FFWSTO
CAC017-251000-
/O.NEW.KSTO.FF.W.0002.211024T1447Z-211025T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Sacramento has issued a

* Flash Flood Warning for...
  The Caldor burn scar in...
  El Dorado County in northern California...

* Until 300 AM PDT Monday.

* At 747 AM PDT, Doppler radar and automated rain gauges indicated 
  heavy rain moving towards the Caldor Burn Scar. Flash flooding is 
  expected to begin within the next several hours. Take action now.

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 Caldor Burn Scar.

  SOURCE...Radar and automated gauges.

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

* Some locations that will experience flash flooding include...
  Kirkwood, Kit Carson, Grizzly Flat, Twin Bridges and Sierra At 
  Tahoe.

This includes the following streams and drainages...
  Tragedy 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 Caldor 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.

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

&&

LAT...LON 3881 12003 3877 12008 3872 12007 3872 12005
      3864 12015 3862 12035 3856 12046 3861 12065
      3862 12055 3868 12057 3866 12065 3866 12066
      3875 12050 3877 12029 3885 12018

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

$$

CM

3 follow-up statements

050 
WGUS76 KSTO 250022
FFSSTO

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

CAC017-251000-
/O.CON.KSTO.FF.W.0002.000000T0000Z-211025T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
El Dorado CA-
522 PM PDT Sun Oct 24 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 3 AM PDT MONDAY FOR 
EL DORADO COUNTY...

At 522 PM PDT, Doppler radar and automated rain gauges indicated 
that heavy rain was falling over the Caldor Burn Scar. Between 2 to 
over 4 inches of rain have fallen. Flash flooding is ongoing or 
expected to begin shortly. Caltrans reported some debris flows, 
flooding and downed trees along the Highway 50 corridor in the 
Caldor Fire burn area. An additional 2 to 5 inches of rain are 
expected during the overnight hours.

Excessive rainfall will continue over the burn scar and will likely 
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 Caldor Burn Scar.

SOURCE...Radar and automated gauges.

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

Some locations that will experience flash flooding include...
  Kirkwood, Kit Carson, Grizzly Flat, Twin Bridges and Sierra At 
  Tahoe.

This includes the following streams and drainages...
  Tragedy 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 Caldor 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.

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3881 12003 3877 12008 3872 12007 3872 12005
      3864 12015 3862 12035 3856 12046 3861 12065
      3862 12055 3868 12057 3866 12065 3866 12066
      3875 12050 3877 12029 3885 12018

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

$$

IDM

143 
WGUS56 KSTO 250945
FFWSTO
CAC017-251600-
/O.EXT.KSTO.FF.W.0002.000000T0000Z-211025T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sacramento CA
245 AM PDT Mon Oct 25 2021

The National Weather Service in Sacramento has extended the

* Flash Flood Warning for...
  The Caldor burn scar in...
  El Dorado County in northern California...

* Until 900 AM PDT Monday.

* At 245 AM PDT, Doppler radar and automated rain gauges indicated 
  moderate to heavy rain continuing to fall over the Caldor Burn 
  Scar. Between 4 and 7 inches of rain have fallen in the past 24 
  hours. An additional 1.5 to 2.5 inches of rain is possible by 6 
  AM. Flash flooding is ongoing or expected to begin shortly.

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 Caldor Burn Scar.

  SOURCE...Radar and automated gauges.

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

* Some locations that will experience flash flooding include...
  Kirkwood, Kit Carson, Grizzly Flat, Twin Bridges and Sierra At 
  Tahoe.

This includes the following streams and drainages...
  Tragedy 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 Caldor 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.

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3881 12003 3877 12008 3872 12007 3872 12005
      3864 12015 3862 12035 3856 12046 3861 12065
      3862 12055 3868 12057 3866 12065 3866 12066
      3875 12050 3877 12029 3885 12018

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1.5-2.5 INCHES IN 3 HOURS

$$

DFR

316 
WGUS76 KSTO 251559
FFSSTO

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

CAC017-251609-
/O.EXP.KSTO.FF.W.0002.000000T0000Z-211025T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
El Dorado CA-
859 AM PDT Mon Oct 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING FOR EL 
DORADO COUNTY...

Rain continues over the area through this morning with a portion of 
the higher elevations of the burn scar receiving snow. Please 
continue to heed remaining road closures.

A Flash Flood Watch remains in effect until 1200 PM PDT for a 
portion of northern California.

LAT...LON 3881 12003 3877 12008 3872 12007 3872 12005
      3864 12015 3862 12035 3856 12046 3861 12065
      3862 12055 3868 12057 3866 12065 3866 12066
      3875 12050 3877 12029 3885 12018

$$

eh

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 24, 5:19 AM PDT	Flash Flood Warning Considerable damage threat	STO	Lassen, Plumas	22 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.