Alert archive / California / Beach Hazards Statements in 2020

Beach Hazards Statement 14, NWS San Francisco Bay Area, CA

December 8, 2020Santa Cruz County, California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Dec 8, 2020, 8:16 PM PST for Santa Cruz County, California. It took effect at Dec 8, 2020, 9:00 PM PST. It was in force for 18 hr.

The area

The counties it named.

The facts

Issued
Dec 8, 2020, 8:16 PM PST (04:16 UTC)
In effect from
Dec 8, 2020, 9:00 PM PST
Expired
Dec 9, 2020, 3:00 PM PST
In force
18 hr
Issued by
NWS San Francisco Bay Area, CA

County Santa Cruz County, CA

The radar

The San Francisco radar (KMUX), 18 km from the middle of the area, began a volume at 04:19 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, 4.3 hours before the alert went out and 80 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 2020-12-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2020-12-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3872 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

839 
WHUS46 KMTR 090416
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
816 PM PST Tue Dec 8 2020

...LARGE LONG PERIOD NORTHWEST SWELL CONTINUES TO BRING HAZARDOUS
CONDITIONS ALONG THE COAST INTO TOMORROW...

We are stepping down our High Surf Warning to a High Surf
Advisory along the coastline from Sonoma to Monterey Counties.
North Monterey Bay, essentially Santa Cruz County is being 
stepped back from a high surf advisory to a beach hazard 
statement.

Large long period swell continues to show at area buoys. From
Point Reyes buoy reading 17 feet @ 17 seconds to Point Sur buoy
reading 14 feet @ 18 seconds, as of 730 PM. This makes for
continued large breaking waves along the coast through the night.
While heights will drop through the night, open ocean swell is 
outperforming the wave models. Therefore we saw the need to extend
some kind of notice that the ocean will remain violently fierce 
into Wednesday. In addition, the periods are remaining up, which 
means lots of water moving and extreme currents will continue, 
especially near jetties, points, and headlands. These currents can
take a person a hundreds of yards in a very short time. Beyond 
the dangers of thundering surf and extreme current, the waters 
remain bone chilling cold with buoys reporting 52-55 degree 
temperatures. Cold water shock followed by cold water paralysis
leads to drownings.

All this to say, breaking waves at the most exposed beaches will 
continue to be in the 15-20 foot range with sets potentially
reaching to 25 feet. Beaches facing west and west-northwest will
be the most impacted.

Stay off rocks and jetties, exposed piers and low lying exposed 
peninsulas. If you are taken into the water without warning and
unprepared, survival is unlikely. Cold water drownings occur each
year with these types of events and are completely avoidable by 
remaining a safe distance from the coastline.

Sheltered areas, such as Capitola, will remain dangerous due to
currents and cold water, even though the wave heights will be
lower than that of the exposed coast.

Do your part. Keep our first responders safe by remaining safe 
yourself.

CAZ006-505-509-530-091230-
/O.EXB.KMTR.SU.Y.0006.201209T0500Z-201209T2300Z/
/O.CON.KMTR.SU.W.0001.000000T0000Z-201209T0500Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
816 PM PST Tue Dec 8 2020

...HIGH SURF WARNING REMAINS IN EFFECT UNTIL 9 PM PST THIS
EVENING...
...HIGH SURF ADVISORY IN EFFECT UNTIL 3 PM PST WEDNESDAY...

* WHAT...Large breaking waves of up to 20 feet, increased wave
  runup, and strong rip current.

* WHERE...San Francisco, Coastal North Bay Including Point Reyes 
  National Seashore, San Francisco Peninsula Coast and Southern 
  Monterey Bay and Big Sur Coast Counties.

* WHEN...For the High Surf Warning, until 9 PM PST this evening.
  For the High Surf Advisory, from 9 PM PST this evening until 3 
  PM PST Wednesday.

* IMPACTS...Large breaking waves can sweep people off jetties and
  docks, and into dangerous seas. Life threatening swimming 
  conditions can be expected. Cold water rescues or drownings are 
  more likely with these waves and stronger rip currents.

* ADDITIONAL INFO...Stay out of the water until conditions become
  much less dangerous.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ529-091230-
/O.NEW.KMTR.BH.S.0014.201209T0500Z-201209T2300Z/
/O.CON.KMTR.SU.Y.0006.000000T0000Z-201209T0500Z/
Northern Monterey Bay-
816 PM PST Tue Dec 8 2020

...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 9 PM PST THIS
EVENING...
...BEACH HAZARDS STATEMENT IN EFFECT THROUGH WEDNESDAY
AFTERNOON...

* WHAT...Large breaking waves of 10-15 feet, increased wave 
  runup, and strong rip current.

* WHERE...Northern Monterey Bay. Santa Cruz County.

* WHEN...For the High Surf Advisory, until 9 PM PST this evening.
  For the Beach Hazards Statement, 9 PM PST this evening through 
  Wednesday afternoon.

* IMPACTS...Dangerous swimming and surfing conditions and
  localized beach erosion. Large breaking waves can sweep people
  off jetties and docks, and into dangerous seas. Cold water
  rescues or drownings are more likely with these waves and
  stronger rip currents.

* ADDITIONAL INFO...Stay out of the water until conditions become
  much less dangerous.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
2 follow-up statements
852 
WHUS46 KMTR 091155
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
355 AM PST Wed Dec 9 2020

...MODERATE TO LONG PERIOD NORTHWEST SWELL CONTINUES TO BRING 
HAZARDOUS CONDITIONS ALONG THE COAST TODAY...

Moderate to long period northwest swell continues to show at area
buoys. From Point Reyes buoy reading 13 feet @ 16 seconds to Point
Sur buoy reading 15 feet @ 15 seconds, as of 300 AM. Expect continued
large breaking waves along the coast today. While heights lower 
overnight, open ocean swell is outperforming the wave models. In 
addition, the periods are remaining up, which means lots of water 
moving and extreme currents will continue, especially near jetties,
points, and headlands. These currents can take a person a hundreds
of yards in a very short time. Beyond the dangers of thundering 
surf and extreme current, the waters remain bone chilling cold 
with buoys reporting 52-55 degree temperatures. Cold water shock 
followed by cold water paralysis leads to drownings.

All this to say, breaking waves at the most exposed beaches will
continue to be in the 15-20 foot range with sets potentially
reaching to 25 feet. Beaches facing west and west-northwest will
be the most impacted.

Stay off rocks and jetties, exposed piers and low lying exposed
peninsulas. If you are taken into the water without warning and
unprepared, survival is unlikely. Cold water drownings occur each
year with these types of events and are completely avoidable by
remaining a safe distance from the coastline.

Sheltered areas, such as Capitola, will remain dangerous due to
currents and cold water, even though the wave heights will be
lower than that of the exposed coast.

Do your part. Keep our first responders safe by remaining safe
yourself.

CAZ006-505-509-530-092300-
/O.CON.KMTR.SU.Y.0006.000000T0000Z-201209T2300Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
355 AM PST Wed Dec 9 2020

...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 3 PM PST THIS
AFTERNOON...

* WHAT...Large breaking waves of up to 20 feet, increased wave 
  runup, and strong rip current. 

* WHERE...San Francisco, Coastal North Bay Including Point Reyes 
  National Seashore, San Francisco Peninsula Coast and Southern 
  Monterey Bay and Big Sur Coast Counties. 

* WHEN...High Surf Advisory until 3 PM PST today. 

* IMPACTS...Large breaking waves can sweep people off jetties 
  and docks, and into dangerous seas. Life threatening swimming 
  conditions can be expected. Cold water rescues or drownings 
  are more likely with these waves and stronger rip currents. 

* ADDITIONAL INFO...Stay out of the water until conditions 
  become much less dangerous. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.

&&

$$

CAZ529-092300-
/O.CON.KMTR.BH.S.0014.000000T0000Z-201209T2300Z/
Northern Monterey Bay-
355 AM PST Wed Dec 9 2020

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 3 PM PST THIS
AFTERNOON...

* WHAT...Large breaking waves of 10-15 feet, increased wave 
  runup, and strong rip current. 

* WHERE...Northern Monterey Bay. Santa Cruz County.

* WHEN...Beach Hazards Statement until 3 PM PST today. 

* IMPACTS...Dangerous swimming and surfing conditions and 
  localized beach erosion. Large breaking waves can sweep people 
  off jetties and docks, and into dangerous seas. Cold water 
  rescues or drownings are more likely with these waves and 
  stronger rip currents. 

* ADDITIONAL INFO...Stay out of the water until conditions 
  become much less dangerous. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced swimmers should remain out of the water due to
dangerous surf conditions.

Remain out of the water to avoid hazardous swimming conditions.

&&

$$
153 
WHUS46 KMTR 092238
CFWMTR

Coastal Hazard Message
National Weather Service San Francisco CA
238 PM PST Wed Dec 9 2020

CAZ006-505-509-530-092345-
/O.EXP.KMTR.SU.Y.0006.000000T0000Z-201209T2300Z/
San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
238 PM PST Wed Dec 9 2020

...HIGH SURF ADVISORY WILL EXPIRE AT 3 PM PST THIS AFTERNOON...

As of 2 pm buoys are still reporting seas from 8 to 13 feet at
around 14 seconds. However sea heights are forecast to slowly
decrease overnight into Thursday. Even though the high surf
advisory will be allowed to expire all visitors to area beaches
should continue to use extra caution as these high energy waves
continue to impact the coastline.

$$

CAZ529-092345-
/O.EXP.KMTR.BH.S.0014.000000T0000Z-201209T2300Z/
Northern Monterey Bay-
238 PM PST Wed Dec 9 2020

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 3 PM PST THIS
AFTERNOON...

As of 2 pm buoys are still reporting seas from 8 to 13 feet at
around 14 seconds. However sea heights are forecast to slowly
decrease overnight into Thursday. Even though the beach hazard
statement will be allowed to expire all visitors to area beaches 
should continue to use extra caution as these high energy waves 
continue to impact the coastline.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 9, 2:11 AM PSTSmall Craft AdvisoryMTR55 hr

Nearby

Beach Hazards Statements in California, 2020Every beach hazards statement in 2020

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.