Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 11, NWS Reno, NV

October 24, 2021Lassen County, Plumas County, California

NWS Reno, NV issued this flash flood warning at Oct 24, 2021, 6:11 AM PDT for Lassen County, Plumas County, California. It was in force for 21 hr. 5 reports 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: Oct 24, 2021, 6:11 AM PDT (13:11 UTC)
Expired: Oct 25, 2021, 3:00 AM PDT
In force: 21 hr
Issued by: NWS Reno, NV
Area: Storm-based polygon
Flood severity: None

Counties Lassen County, CA, Plumas County, CA

The radar

The Beale AFB radar (KBBX), 103 km from the middle of the area, began a volume at 13:10 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

Time	Report	Where	Remark
Oct 24, 7:56 AM PDT	HEAVY RAIN 0.97	4 Ssw Fredonyer Pass, CA	MESONET STATION WWDC1 WESTWOOD.
Oct 24, 8:00 AM PDT	HEAVY RAIN 1.05	5 Nne Cromberg, CA	MESONET STATION GRZC1 4.6 NE CROMBERG.
Oct 24, 8:15 AM PDT	HEAVY RAIN 0.94	5 Nnw Antelope Lake, CA	MESONET STATION PIEC1 PIERCE.
Oct 24, 3:15 PM PDT	HEAVY RAIN 2.58	5 Nnw Antelope Lake, CA	MESONET STATION PIEC1 PIERCE.
Oct 25, 2:56 AM PDT	HEAVY RAIN 3.45	4 Ssw Fredonyer Pass, CA	MESONET STATION WWDC1 WESTWOOD.

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

The nearest sounding before it

Reno, NV (KREV), launched 12:00Z, 1.2 hours before the alert went out and 232 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: 1043 m above ground
0-6 km bulk shear: 65 kt
0-1 km storm-relative helicity: 270 m²/s²
0-3 km storm-relative helicity: 689 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

225 
WGUS55 KREV 241311
FFWREV
CAC035-063-251000-
/O.NEW.KREV.FF.W.0011.211024T1311Z-211025T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Reno NV
611 AM PDT Sun Oct 24 2021

The National Weather Service in Reno has issued a

* Flash Flood Warning for...
  The Dixie and Sheep burn scar in...
  West Central Lassen County in northern California...
  Plumas County in northern California...

* Until 300 AM PDT Monday.

* At 611 AM PDT, Doppler radar and automated rain gauges indicated 
  heavy rain falling over the Dixie and Sheep Burn Scar. Between 0.2 
  and 0.5 inches of rain have fallen. Additional rainfall amounts of 
  2 to 3 inches are possible in the warned area. Flash flooding is 
  expected to begin within the next several hours.

  HAZARD...Flash flooding caused by heavy rain in and around the
           Dixie and Sheep Burn Scars.

  SOURCE...Radar and automated gauges.

  IMPACT...Flooding of areas in and around the Dixie and Sheep
           Burn Scar.

* Some locations that will experience flash flooding include...
  Susanville, North Arm of Indian Valley, Antelope Lake, Genesee, 
  Westwood, Lone Rock Campground, Boulder Creek Campground, Long 
  Point Campground, Fredonyer Pass, Cromberg and Lightning Tree 
  Campground.

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 and Sheep 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 stream beds 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 4023 12104 4034 12093 4039 12081 4039 12066
      4037 12055 4028 12065 4011 12053 3991 12043
      3990 12052 3988 12064 3993 12075 3997 12078
      4020 12089 4019 12089 4019 12093 4021 12093
      4021 12095 4022 12095 4022 12100 4023 12100

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Tolby

1 follow-up statement

857 
WGUS75 KREV 242025
FFSREV

Flash Flood Statement
National Weather Service Reno NV
125 PM PDT Sun Oct 24 2021

CAC035-063-251000-
/O.CON.KREV.FF.W.0011.000000T0000Z-211025T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lassen CA-Plumas CA-
125 PM PDT Sun Oct 24 2021

...FLASH FLOOD WARNING FOR THE DIXIE AND SHEEP BURN SCAR REMAINS IN 
EFFECT UNTIL 3 AM PDT MONDAY FOR WEST CENTRAL LASSEN AND PLUMAS 
COUNTIES...

At 125 PM PDT, Doppler radar and automated rain gauges indicated 
that heavy rain was falling over the Dixie and Sheep Burn Scar. 
Between 1 and 2 inches of rain have fallen. Additional rainfall 
amounts of 2 to 3 inches are possible in the warned area. Flash 
flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by heavy rain in and around the
         Dixie and Sheep Burn Scars.

SOURCE...Radar and automated gauges.

IMPACT...Flooding of areas in and around the Dixie and Sheep Burn
         Scar.

Some locations that will experience flash flooding include...
Susanville, North Arm of Indian Valley, Antelope Lake, Genesee, 
Westwood, Lone Rock Campground, Boulder Creek Campground, Long Point 
Campground, Fredonyer Pass, Cromberg and Lightning Tree Campground.

The heaviest rain rates are anticipated this afternoon through early 
evening on the burn scar.

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 and Sheep 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 stream beds 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 4023 12104 4034 12093 4039 12081 4039 12066
      4037 12055 4028 12065 4011 12053 3991 12043
      3990 12052 3988 12064 3993 12075 3997 12078
      4020 12089 4019 12089 4019 12093 4021 12093
      4021 12095 4022 12095 4022 12100 4023 12100

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

DJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 24, 6:42 AM PDT	Flash Flood Warning	REV	Lassen, Plumas	20 hr
Oct 24, 8:00 AM PDT	Areal Flood Advisory	REV	Lassen, Plumas, Sierra	3 hr
Oct 24, 11:12 AM PDT	Areal Flood Warning	REV	Lassen, Nevada, Plumas, Sierra	2 hr
Oct 24, 1:19 PM PDT	Areal Flood Warning	REV	Alpine, El Dorado, Lassen, Nevada, Placer, Plumas and 1 more	8 hr
Oct 24, 3:27 PM PDT	River Flood Warning	REV	Nevada, Placer	11 hr
Oct 24, 4:47 PM PDT	Areal Flood Warning	REV	Alpine, El Dorado, Mono	12 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; radar from the NEXRAD Level II archive.