Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 14, NWS San Francisco Bay Area, CA

October 25, 2021Monterey County, California

NWS San Francisco Bay Area, CA issued this flash flood warning at Oct 25, 2021, 1:07 AM PDT for Monterey County, California. It was in force for 4 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 25, 2021, 1:07 AM PDT (08:07 UTC)
Expired
Oct 25, 2021, 5:00 AM PDT
In force
4 hr
Issued by
NWS San Francisco Bay Area, CA
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Monterey County, CA

The radar

The San Francisco radar (KMUX), 124 km from the middle of the area, began a volume at 08:09 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 00:00Z, 8.1 hours before the alert went out and 193 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-pSkew-T log-p diagram, Oakland, CA at 00:00Z on 2021-10-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 00:00Z on 2021-10-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 377 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer LCL
472 m above ground
0-6 km bulk shear
83 kt
0-1 km storm-relative helicity
377 m²/s²
0-3 km storm-relative helicity
444 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

852 
WGUS56 KMTR 250807
FFWMTR
CAC053-251200-
/O.NEW.KMTR.FF.W.0014.211025T0807Z-211025T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Francisco CA
107 AM PDT Mon Oct 25 2021

The National Weather Service in San Francisco has issued a

* Flash Flood Warning for...
  The Dolan and Willow burn area in...
  Southwestern Monterey County in central California...

* Until 500 AM PDT.

* At 107 AM PDT, Doppler radar and automated rain gauges indicated 
  heavy rain falling over the Dolan and Willow Burn Areas. Between 
  0.5 and 1 inch of rain has fallen. Additional rainfall amounts of 
  2 to 4 inches are possible in the warned area. Flash flooding is 
  ongoing or expected to begin shortly.

Excessive rainfall over the burn area will result in debris flow 
moving through the Dolan and Willow Fire burn areas. 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 Dolan and Willow Burn
           Area.

  SOURCE...Radar and automated gauges.

  IMPACT...Life threatening flash flooding of areas in and around
           the Dolan and Willow Burn Areas.

* Some locations that will experience flash flooding include...
  Lucia and Esalen Institute.

There is also a high likelihood of debris and/or rocks impacting 
highway one.

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 Dolan and Willow Burn Areas. 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 arroyos 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.

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

&&

LAT...LON 3597 12145 3594 12147 3601 12150 3605 12159
      3618 12167 3618 12163 3613 12159 3621 12149
      3620 12147 3620 12148 3617 12145 3618 12148
      3615 12148 3615 12142 3613 12138 3600 12126
      3597 12126 3596 12135

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

$$

MM
2 follow-up statements
664 
WGUS76 KMTR 250955
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
255 AM PDT Mon Oct 25 2021

CAC053-251200-
/O.CON.KMTR.FF.W.0014.000000T0000Z-211025T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Monterey CA-
255 AM PDT Mon Oct 25 2021

...FLASH FLOOD WARNING FOR THE DOLAN AND WILLOW BURN AREA REMAINS IN 
EFFECT UNTIL 5 AM PDT EARLY THIS MORNING FOR SOUTHWESTERN MONTEREY 
COUNTY...

At 255 AM PDT, Doppler radar and automated rain gauges indicated 
that heavy rain was falling over the Dolan and Willow Burn Areas. 
Between 0.5 and 1.5 inches of rain have fallen. Additional rainfall 
amounts of 2 to 4 inches are possible in the warned area. Flash 
flooding is ongoing or expected to begin shortly.

Excessive rainfall over the burn area will result in debris flow 
moving through the Dolan and Willow Fire burn area. 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 Dolan and Willow Burn
         Areas.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of areas in and around
         the Dolan and Willow Burn Areas.

Some locations that will experience flash flooding include...
  Lucia and Esalen Institute.

There is also a high likelihood of debris and/or rocks impacting 
highway one.

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 Dolan and Willow Burn Area. 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 arroyos 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.

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

&&

LAT...LON 3597 12145 3594 12147 3601 12150 3605 12159
      3618 12167 3618 12163 3613 12159 3621 12149
      3620 12147 3620 12148 3617 12145 3618 12148
      3615 12148 3615 12142 3613 12138 3600 12126
      3597 12126 3596 12135

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

$$

MM
204 
WGUS76 KMTR 251156
FFSMTR

Flash Flood Statement
National Weather Service San Francisco CA
456 AM PDT Mon Oct 25 2021

CAC053-251206-
/O.EXP.KMTR.FF.W.0014.000000T0000Z-211025T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Monterey CA-
456 AM PDT Mon Oct 25 2021

...FLASH FLOOD WARNING FOR THE DOLAN AND WILLOW BURN AREA WILL 
EXPIRE AT 5 AM PDT EARLY THIS MORNING FOR SOUTHWESTERN MONTEREY 
COUNTY...

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

LAT...LON 3597 12145 3594 12147 3601 12150 3605 12159
      3618 12167 3618 12163 3613 12159 3621 12149
      3620 12147 3620 12148 3617 12145 3618 12148
      3615 12148 3615 12142 3613 12138 3600 12126
      3597 12126 3596 12135

$$

MM

The office that day

Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 24, 8:19 PM PDTAreal Flood AdvisoryMTRMonterey, San Benito, San Mateo, Santa Clara, Santa Cruz9 hr

Nearby

Flash Flood Warnings in California, 2021Every 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.