Alert archive / California / Flash Flood Warnings in 2023

Flash Flood Warning 3, NWS Eureka, CA

August 24, 2023Trinity County, California

NWS Eureka, CA issued this flash flood warning at Aug 24, 2023, 5:02 PM PDT for Trinity County, California. It was in force for 66 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 24, 2023, 5:02 PM PDT (00:02 UTC)
Expired: Aug 24, 2023, 6:08 PM PDT
In force: 66 min
Issued by: NWS Eureka, CA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 87 km from the middle of the area, began a volume at 00:03 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 00:00Z, 0.0 hours before the alert went out and 179 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: 226 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 3182 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 89 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

201 
WGUS56 KEKA 250002
FFWEKA
CAC105-250130-
/O.NEW.KEKA.FF.W.0003.230825T0002Z-230825T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Eureka CA
502 PM PDT Thu Aug 24 2023

The National Weather Service in Eureka has issued a

* Flash Flood Warning for...
  The Monument burn scar in...
  West Central Trinity County in northwestern California...

* Until 630 PM PDT.

* At 502 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Monument Burn Scar. Flash flooding is ongoing 
  or expected to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through the area from Del Loma to Burnt Ranch including 
Highway 299. The debris flow can consist of rock, mud, vegetation 
and other loose materials.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding in and around the Monument
           Burn Scar.

  SOURCE...Radar.

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

* Some locations that will experience flash flooding include...
  Del Loma.

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 Monument 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.

&&

LAT...LON 4081 12325 4076 12328 4071 12329 4070 12341
      4074 12348 4088 12346 4089 12343 4090 12342
      4086 12335 4092 12328

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

$$

SEC

1 follow-up statement

802 
WGUS76 KEKA 250108
FFSEKA

Flash Flood Statement
National Weather Service Eureka CA
608 PM PDT Thu Aug 24 2023

CAC105-250118-
/O.CAN.KEKA.FF.W.0003.000000T0000Z-230825T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Trinity CA-
608 PM PDT Thu Aug 24 2023

...FLASH FLOOD WARNING FOR THE MONUMENT BURN SCAR IS CANCELLED FOR 
WEST CENTRAL TRINITY COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4081 12325 4076 12328 4071 12329 4070 12341
      4074 12348 4088 12346 4089 12343 4090 12342
      4086 12335 4092 12328

$$

KMZ

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 24, 5:53 PM PDT	Special Weather Statement	EKA	Humboldt	37 min

Nearby

Flash Flood Warnings in California, 2023 Every flash flood warning in 2023

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.