Alert archive / California / Beach Hazards Statements in 2017

Beach Hazards Statement 10, NWS San Francisco Bay Area, CA

October 20, 20176 counties in California

NWS San Francisco Bay Area, CA issued this beach hazards statement at Oct 20, 2017, 1:01 PM PDT for 6 counties in California. It took effect at Oct 20, 2017, 6:00 PM PDT. It was in force for 27 hr.

The area

The counties it named.

The facts

Issued
Oct 20, 2017, 1:01 PM PDT (20:01 UTC)
In effect from
Oct 20, 2017, 6:00 PM PDT
Expired
Oct 21, 2017, 9:00 PM PDT
In force
27 hr
Issued by
NWS San Francisco Bay Area, CA

Counties City and County of San Francisco, CA, Marin County, CA, Monterey County, CA, San Mateo County, CA, Santa Cruz County, CA, Sonoma County, CA

The radar

The San Francisco radar (KMUX), 53 km from the middle of the area, began a volume at 20:03 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

Oakland, CA (KOAK), launched 12:00Z, 8.0 hours before the alert went out and 26 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 12:00Z on 2017-10-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 2017-10-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 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
2 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
720 m above ground
0-6 km bulk shear
71 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
50 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

024 
WHUS46 KMTR 202001
CFWMTR

COASTAL HAZARD MESSAGE
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
101 PM PDT FRI OCT 20 2017

...HIGH SURF EXPECTED THROUGH THIS EVENING WITH CONTINUED BEACH 
HAZARDS THROUGH SATURDAY...

.A LARGE NORTHWEST SWELL OF 15 TO 18 FEET WITH PERIODS OF 15 TO 
18 SECONDS PEAKED FRIDAY MORNING AND IS TAPERING OFF THROUGH THE 
REMAINDER OF THE DAY. THIS SWELL WILL RESULT IN BREAKING WAVES OF 
GENERALLY AROUND 15 FEET, OCCASIONALLY 20 TO 25 FEET AT FAVORED 
LOCATIONS. THESE CONDITIONS WILL POSE A THREAT TO BEACHGOERS AND 
MARINERS TRAVERSING HARBOR ENTRANCES LATE THIS WEEK. THE HIGH SURF
ADVISORY WILL EXPIRE AT 6PM BUT BE REPLACED BY A BEACH HAZARD 
STATEMENTS AS THE SEAS GRADUALLY SUBSIDE.

CAZ006-505-509-529-530-210115-
/O.NEW.KMTR.BH.S.0010.171021T0100Z-171022T0400Z/
/O.CON.KMTR.SU.Y.0007.000000T0000Z-171021T0100Z/
SAN FRANCISCO-
COASTAL NORTH BAY INCLUDING POINT REYES NATIONAL SEASHORE-
SAN FRANCISCO PENINSULA COAST-NORTHERN MONTEREY BAY-
SOUTHERN MONTEREY BAY AND BIG SUR COAST-
101 PM PDT FRI OCT 20 2017

...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 6 PM PDT THIS
EVENING...
...BEACH HAZARDS STATEMENT IN EFFECT FROM 6 PM PDT THIS EVENING
THROUGH SATURDAY EVENING...

THE NATIONAL WEATHER SERVICE IN SAN FRANCISCO HAS ISSUED A BEACH
HAZARDS STATEMENT FOR SNEAKER WAVES, LARGE SHORE BREAK, AND
INCREASED RISK OF RIP CURRENTS WHICH IS IN EFFECT FROM 6 PM PDT 
THIS EVENING THROUGH SATURDAY EVENING.

* WAVES AND SURF...BREAKING WAVES OF AROUND 15 FEET, OCCASIONALLY
  UP TO 25 FEET, WITH PERIODS OF 15 TO 18 SECONDS. FOR 
  SATURDAY... BREAKING WAVES OF 8 TO 13 FEET WITH PERIODS OF 13 TO
  15 SECONDS.

* TIMING...WAVES PEAKING FRI MORNING... TAPERING OFF LATER FRI...
  WITH CONTINUED BEACH HAZARDS FRIDAY NIGHT THROUGH SATURDAY. 

* LOCATION...COASTLINE FROM SONOMA COUNTY SOUTH THROUGH MONTEREY
  COUNTY. IN PARTICULAR WEST TO NORTHWEST FACING
  BEACHES...INCLUDING BUT NOT LIMITED TO...OCEAN BEACH...MONTARA
  STATE BEACH AND MARINA STATE BEACH.

* IMPACTS...LARGE BREAKING WAVES ALONG THE COAST WILL LEAD TO 
  INCREASED WAVE RUN-UP ON BEACHES WITH WAVES TOPPING AND 
  WASHING OVER LARGE ROCKS AND JETTIES. THESE LARGE WAVES CAN BE 
  ERRATIC AND UNPREDICTABLE. USE EXTRA CAUTION NEAR THE SURF 
  ZONE AS THESE LARGE WAVES WILL BE CAPABLE OF SWEEPING PEOPLE 
  INTO THE FRIGID AND TURBULENT OCEAN WATER. MARINERS TRAVERSING 
  THE BAR OR HARBOR ENTRANCES ARE ALSO URGED TO EXERCISE EXTREME 
  CAUTION...OR STAY IN PORT UNTIL THE THREAT SUBSIDES. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH SURF ADVISORY MEANS THAT HIGH SURF WILL AFFECT BEACHES IN
THE ADVISORY AREA...PRODUCING RIP CURRENTS AND LOCALIZED BEACH
EROSION.

A BEACH HAZARD STATEMENT MEANS THE POTENTIALLY DANGEROUS
CONDITIONS MAY EXIST ON SPECIFIC BEACHES. THESE HAZARDS MAY
INCLUDE LARGE SHORE BREAK...STRONG RIP CURRENTS...STRONG LONGSHORE
CURRENTS AND POSSIBLY SNEAKER WAVES. ALL OF WHICH COULD BE LIFE
THREATENING. BE SURE TO ALWAYS KEEP YOUR EYES ON THE OCEAN.

&&

$$
4 follow-up statements
905 
WHUS46 KMTR 210100
CFWMTR

COASTAL HAZARD MESSAGE
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
600 PM PDT FRI OCT 20 2017

...HIGH SURF ADVISORY EXPIRES AT 6 PM AND WILL BE REPLACED WITH A
BEACH HAZARDS STATEMENT THROUGH SATURDAY EVENING...

.A LARGE NORTHWEST SWELL OF 15 TO 18 FEET WITH PERIODS OF 15 TO
18 SECONDS PEAKED EARLIER TODAY AND WILL CONTINUE TO TAPER OFF
THROUGH THE OVERNIGHT HOURS. THIS SWELL WILL RESULT IN BREAKING 
WAVES OF GENERALLY AROUND 12 TO 15 FEET, OCCASIONALLY REACHING UP
TO 20 FEET AT FAVORED LOCATIONS. THESE CONDITIONS WILL POSE A 
THREAT TO BEACHGOERS AND MARINERS TRAVERSING HARBOR ENTRANCES
THROUGH SATURDAY EVENING.

CAZ006-505-509-529-530-210900-
/O.EXP.KMTR.SU.Y.0007.000000T0000Z-171021T0100Z/
/O.CON.KMTR.BH.S.0010.000000T0000Z-171022T0400Z/
SAN FRANCISCO-
COASTAL NORTH BAY INCLUDING POINT REYES NATIONAL SEASHORE-
SAN FRANCISCO PENINSULA COAST-NORTHERN MONTEREY BAY-
SOUTHERN MONTEREY BAY AND BIG SUR COAST-
600 PM PDT FRI OCT 20 2017

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH SATURDAY
EVENING...
...HIGH SURF ADVISORY WILL EXPIRE AT 6 PM PDT THIS EVENING...

* SEAS...A NORTHWESTERLY SWELL OF 12 TO 15 FT AT 15 TO 17 SECONDS
  WILL CONTINUE TO CREATE HAZARDOUS BEACH CONDITIONS. BREAKING 
  WAVES MAY REACH UP TO 20 FEET AT FAVORED LOCATIONS.

* TIMING...THROUGH SATURDAY EVENING. WAVES ALREADY PEAKED EARLIER
  FRIDAY AND WILL CONTINUE TO DIMINISH OVERNIGHT AND INTO
  SATURDAY. WAVES OF GENERALLY AROUND 12 TO 15 FEET, OCCASIONALLY
  REACHING UP TO 20 FEET AT FAVORED LOCATIONS.

* LOCATION...COASTLINE FROM SONOMA COUNTY SOUTH THROUGH MONTEREY 
  COUNTY. IN PARTICULAR WEST TO NORTHWEST FACING BEACHES... 
  INCLUDING BUT NOT LIMITED TO...OCEAN BEACH...MONTARA STATE 
  BEACH AND MARINA STATE BEACH. 

LARGE BREAKING WAVES ALONG THE COAST WILL LEAD TO INCREASED WAVE 
RUN-UP ON BEACHES WITH WAVES TOPPING AND WASHING OVER LARGE ROCKS 
AND JETTIES. THESE LARGE WAVES CAN BE ERRATIC AND UNPREDICTABLE. 
USE EXTRA CAUTION NEAR THE SURF ZONE AS THESE LARGE WAVES WILL BE 
CAPABLE OF SWEEPING PEOPLE INTO THE FRIGID AND TURBULENT OCEAN 
WATER. MARINERS TRAVERSING THE BAR OR HARBOR ENTRANCES ARE ALSO 
URGED TO EXERCISE EXTREME CAUTION...OR STAY IN PORT UNTIL THE 
THREAT SUBSIDES.

&&

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A BEACH HAZARD STATEMENT MEANS THE POTENTIALLY DANGEROUS
CONDITIONS MAY EXIST ON SPECIFIC BEACHES. THESE HAZARDS MAY
INCLUDE LARGE SHORE BREAK...STRONG RIP CURRENTS...STRONG LONGSHORE
CURRENTS AND POSSIBLY SNEAKER WAVES. ALL OF WHICH COULD BE LIFE
THREATENING. BE SURE TO ALWAYS KEEP YOUR EYES ON THE OCEAN.

&&

$$
980 
WHUS46 KMTR 210544
CFWMTR

COASTAL HAZARD MESSAGE
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1044 PM PDT FRI OCT 20 2017

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH SATURDAY 
EVENING...

.NORTHWEST SWELLS OF 12 TO 15 FEET WITH PERIODS OF 15 TO 17
SECONDS WILL CONTINUE THROUGH THE COASTAL WATERS THROUGH SATURDAY
EVENING. THIS SWELL WILL RESULT IN BREAKING WAVES GENERALLY 
AROUND 12 TO 15 FEET, OCCASIONALLY REACHING UP TO 20 FEET AT 
FAVORED LOCATIONS. WAVES HEIGHTS WILL GRADUALLY DIMINISH THROUGH
THE DAY ON SATURDAY. THESE CONDITIONS WILL POSE A THREAT TO 
BEACHGOERS AND MARINERS TRAVERSING HARBOR ENTRANCES THROUGH 
SATURDAY EVENING.

CAZ006-505-509-529-530-211800-
/O.CON.KMTR.BH.S.0010.000000T0000Z-171022T0400Z/
SAN FRANCISCO-
COASTAL NORTH BAY INCLUDING POINT REYES NATIONAL SEASHORE-
SAN FRANCISCO PENINSULA COAST-NORTHERN MONTEREY BAY-
SOUTHERN MONTEREY BAY AND BIG SUR COAST-
1044 PM PDT FRI OCT 20 2017

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH SATURDAY
EVENING...

* SEAS...A NORTHWESTERLY SWELL OF 12 TO 15 FT AT 15 TO 17 
  SECONDS WILL CONTINUE TO CREATE HAZARDOUS BEACH CONDITIONS. 
  BREAKING WAVES MAY REACH UP TO 20 FEET AT FAVORED LOCATIONS. 

* TIMING...THROUGH SATURDAY EVENING. WAVES ALREADY PEAKED EARLIER
  FRIDAY AND WILL CONTINUE TO GRADUALLY DIMINISH INTO SATURDAY.
  WAVES WILL GENERALLY BE 12 TO 15 FEET, OCCASIONALLY REACHING UP
  TO 20 FEET AT FAVORED LOCATIONS. 

* LOCATION...COASTLINE FROM SONOMA COUNTY SOUTH THROUGH MONTEREY
  COUNTY. IN PARTICULAR WEST TO NORTHWEST FACING BEACHES, 
  INCLUDING BUT NOT LIMITED TO OCEAN BEACH, MONTARA STATE BEACH, 
  AND MARINA STATE BEACH. 

* POTENTIAL IMPACTS...INCREASED RISK OF RIP CURRENTS, SNEAKER
  WAVES, AND LOCALLY LARGE SURF BREAK. BEACHGOERS MAY BE KNOCKED
  OVER, INJURED, OR PULLED OUT TO SEA INTO THE COLD, RESTLESS
  OCEAN.

A BEACH HAZARD STATEMENT MEANS THE POTENTIALLY DANGEROUS
CONDITIONS MAY EXIST ON SPECIFIC BEACHES. THESE HAZARDS MAY
INCLUDE LARGE SHORE BREAK, STRONG RIP CURRENTS, STRONG LONGSHORE 
CURRENTS AND POSSIBLY SNEAKER WAVES. ALL OF WHICH COULD BE LIFE- 
THREATENING. BE SURE TO ALWAYS KEEP YOUR EYES ON THE OCEAN.

&&

$$
908 
WHUS46 KMTR 211615
CFWMTR

COASTAL HAZARD MESSAGE
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
915 AM PDT SAT OCT 21 2017

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH 9PM SATURDAY 
EVENING... 

.NORTHWEST SWELLS OF 12 TO 15 FEET WITH PERIODS OF 14 TO
16 SECONDS WILL CONTINUE THROUGH THE COASTAL WATERS THROUGH
SATURDAY EVENING. THIS SWELL WILL RESULT IN BREAKING WAVES
GENERALLY AROUND 12 TO 15 FEET, OCCASIONALLY REACHING UP TO
20 FEET AT FAVORED LOCATIONS. WAVES HEIGHTS WILL GRADUALLY
DIMINISH THROUGH THE DAY ON SATURDAY. THESE CONDITIONS WILL POSE
A THREAT TO BEACHGOERS AND MARINERS TRAVERSING HARBOR ENTRANCES
THROUGH SATURDAY EVENING.

CAZ006-505-509-529-530-220400-
/O.CON.KMTR.BH.S.0010.000000T0000Z-171022T0400Z/
SAN FRANCISCO-
COASTAL NORTH BAY INCLUDING POINT REYES NATIONAL SEASHORE-
SAN FRANCISCO PENINSULA COAST-NORTHERN MONTEREY BAY-
SOUTHERN MONTEREY BAY AND BIG SUR COAST-
915 AM PDT SAT OCT 21 2017

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 9 PM PDT THIS
EVENING...

* SEAS...A NORTHWESTERLY SWELL OF 12 TO 15 FT AT 14 TO 16 
  SECONDS WILL CONTINUE TO CREATE HAZARDOUS BEACH CONDITIONS. 
  BREAKING WAVES MAY REACH UP TO 20 FEET AT FAVORED LOCATIONS. 

* TIMING...THROUGH SATURDAY EVENING. WAVES ALREADY PEAKED 
  EARLIER FRIDAY AND WILL CONTINUE TO GRADUALLY DIMINISH INTO 
  SATURDAY. WAVES WILL GENERALLY BE 12 TO 15 FEET, OCCASIONALLY 
  REACHING UP TO 20 FEET AT FAVORED LOCATIONS. 

* LOCATION...COASTLINE FROM SONOMA COUNTY SOUTH THROUGH MONTEREY 
  COUNTY. IN PARTICULAR WEST TO NORTHWEST FACING BEACHES, 
  INCLUDING BUT NOT LIMITED TO OCEAN BEACH, MONTARA STATE BEACH, 
  AND MARINA STATE BEACH. 

* POTENTIAL IMPACTS...INCREASED RISK OF RIP CURRENTS, SNEAKER 
  WAVES, AND LOCALLY LARGE SURF BREAK. BEACHGOERS MAY BE KNOCKED 
  OVER, INJURED, OR PULLED OUT TO SEA INTO THE COLD, RESTLESS 
  OCEAN. 

A BEACH HAZARD STATEMENT MEANS THE POTENTIALLY DANGEROUS
CONDITIONS MAY EXIST ON SPECIFIC BEACHES. THESE HAZARDS MAY
INCLUDE LARGE SHORE BREAK, STRONG RIP CURRENTS, STRONG LONGSHORE
CURRENTS AND POSSIBLY SNEAKER WAVES. ALL OF WHICH COULD BE LIFE-
THREATENING. BE SURE TO ALWAYS KEEP YOUR EYES ON THE OCEAN.

&&

$$
822 
WHUS46 KMTR 220343
CFWMTR

COASTAL HAZARD MESSAGE
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
843 PM PDT SAT OCT 21 2017

CAZ006-505-509-529-530-220445-
/O.EXP.KMTR.BH.S.0010.000000T0000Z-171022T0400Z/
SAN FRANCISCO-
COASTAL NORTH BAY INCLUDING POINT REYES NATIONAL SEASHORE-
SAN FRANCISCO PENINSULA COAST-NORTHERN MONTEREY BAY-
SOUTHERN MONTEREY BAY AND BIG SUR COAST-
843 PM PDT SAT OCT 21 2017

...BEACH HAZARDS STATEMENT WILL BE ALLOWED TO EXPIRE AT 9 PM PDT 
THIS EVENING...

NORTHWESTERLY SWELL PERIODS WILL GRADUALLY DECREASE THROUGH SUNDAY
NIGHT. LOCALLY DANGEROUS RIP CURRENTS ARE STILL POSSIBLE TONIGHT, 
HOWEVER THE RISK OF RIP CURRENTS WILL BE ON THE DECREASE AS SWELL
PERIODS DECREASE THROUGH SUNDAY NIGHT. OF COURSE IT'S ALWAYS PRUDENT
TO USE EXTRA CARE WHENEVER VENTURING CLOSE TO THE OCEAN'S EDGE.

&&

$$

Nearby

Beach Hazards Statements in California, 2017Every beach hazards statement in 2017

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.