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Beach Hazards Statement

Coastal Hazard Message
National Weather Service San Francisco CA
235 PM PST Thu Dec 3 2020

...Very Long Period Swell will bring Dangerous Sneaker Waves...

Beach Hazard Statement has been extended into Friday afternoon.

Long period swell will continue into Friday which will maintain
the increased risk of sneaker waves and strong rip currents. While
swell will peak overnight in the around 12-14 feet at 17-18
seconds, it will have a slow decline through much of Friday.

Sneaker waves are waves that seem to come out of nowhere and can
have a periodicity of minutes to tens of minutes. A deceptively
calm ocean typically exist between the sets of sneaker waves.
These consequently may catch those on coastal jetties, rocks,
piers, or shorelines offguard and may injure them or knock them
into the cold, turbulent ocean. Beachcombing is not advised during
this timeframe. In addition, strong rip currents will accompany
the energetic wave train, particularly at WNW facing beaches.
These types of events claim lives each year along our coast so
extreme vigilance is advised if visiting the coast.

San Francisco-
Coastal North Bay Including Point Reyes National Seashore-
San Francisco Peninsula Coast-
Southern Monterey Bay and Big Sur Coast-
235 PM PST Thu Dec 3 2020


* WHAT...A very long period WNW swell will continue to bring a
  threat of dangerous sneaker waves to area beaches, as well as
  strong rip currents. Moderate to large breaking waves towards
  the end of the event this afternoon.

* WHEN...Through Friday afternoon.

* WHERE...Entire coast from Sonoma County southward to the Big
  Sur coast of Monterey County. Excluding the sheltered northern
  portion of the Monterey Bay. The main impacts will be felt at
  W- WNW beaches,including but not limited to: Ocean beach,
  Montara state beach, Half Moon Bay state beach, Manresa state
  beach, and Marina state beach.

* IMPACTS...Sneaker waves will create dangerous conditions at area
  beaches. Steep beaches will have a higher risk of sneaker wave
  activity with greater wave run-up onto beaches. Occasionally
  larger waves will also wash over jetties and rock outcroppings
  that normally stay dry.


A Beach Hazard Statement for sneaker waves means that conditions
are present to support an increased danger of unsuspecting beach
goers being swept into the sea by a wave. People walking along
the beach should never turn their back to the sea. Fisherman
should avoid fishing from rocks or jetties. Beachcombing is not



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