Alert archive / California / Beach Hazards Statements in 2023

Beach Hazards Statement 1, NWS Eureka, CA

January 20, 2023Del Norte County, Humboldt County, Mendocino County, California

NWS Eureka, CA issued this beach hazards statement at Jan 20, 2023, 3:46 AM PST for Del Norte County, Humboldt County, Mendocino County, California. It took effect at Jan 20, 2023, 7:00 PM PST. It was in force for 26 hr.

The area

The counties it named.

The facts

Issued
Jan 20, 2023, 3:46 AM PST (11:46 UTC)
In effect from
Jan 20, 2023, 7:00 PM PST
Expired
Jan 21, 2023, 9:00 PM PST
In force
26 hr
Issued by
NWS Eureka, CA

Counties Del Norte County, CA, Humboldt County, CA, Mendocino County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 47 km from the middle of the area, began a volume at 11:48 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, 11.8 hours before the alert went out and 210 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, Medford/Jackson, OR at 00:00Z on 2023-01-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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, Medford/Jackson, OR at 00:00Z on 2023-01-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 square meters per square second.1939587897Sfc1 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
-5 J/kg
Mixed-layer LCL
784 m above ground
0-6 km bulk shear
62 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

436 
WHUS46 KEKA 201146
CFWEKA

Coastal Hazard Message
National Weather Service Eureka CA
346 AM PST Fri Jan 20 2023

...Long Period Swell Moving in Friday Evening

Long period forerunners will start filling in Friday afternoon.
The wave size will be sufficient for sneaker waves by Friday 
evening. The swell will be near 8 feet at 18 seconds by early 
Saturday morning. Steep beaches will have a higher risk of sneaker
wave activity with greater wave run- up onto beaches. Large waves
will also wash over jetties and rock outcroppings that may 
normally stay dry.
 
CAZ101-103-104-109-202000-
/O.NEW.KEKA.BH.S.0001.230121T0300Z-230122T0000Z/
Coastal Del Norte-Northern Humboldt Coast-Southwestern Humboldt-
Mendocino Coast-
346 AM PST Fri Jan 20 2023

...BEACH HAZARDS STATEMENT IN EFFECT FROM THIS EVENING THROUGH
SATURDAY AFTERNOON...

* WHAT...Increased risk for sneaker waves. There may be periods 
  of lulls in wave activity for up to 30 minutes before larger 
  sets of waves return. 

* WHERE...Coastal Del Norte, Northern Humboldt Coast, 
  Southwestern Humboldt and Mendocino Coast Counties.

* WHEN...From this evening through Saturday afternoon.. .

* IMPACTS...Large, unexpected waves can sweep across the beach 
  without warning, sweeping people into the sea from rocks, 
  jetties, and beaches. These waves can also move large objects 
  such as logs, crushing anyone caught underneath.

* ADDITIONAL DETAILS...Sneaker waves occur when a larger set of
  waves occurs after 20 to 30 minutes of smaller waves.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$
7 follow-up statements
690 
WHUS46 KEKA 201227
CFWEKA

Coastal Hazard Message
National Weather Service Eureka CA
427 AM PST Fri Jan 20 2023

...Long Period Swell Moving in Friday Evening

Long period forerunners will start filling in Friday afternoon.
The wave size will be sufficient for sneaker waves by Friday
evening. The swell will be near 8 feet at 18 seconds by early
Saturday morning. Steep beaches will have a higher risk of
sneaker wave activity with greater wave run- up onto beaches.
Large waves will also wash over jetties and rock outcroppings
that may normally stay dry.

CAZ103-202030-
/O.NEW.KEKA.CF.Y.0002.230120T1700Z-230120T1900Z/
/O.CON.KEKA.BH.S.0001.230121T0300Z-230122T0000Z/
Northern Humboldt Coast-
427 AM PST Fri Jan 20 2023

...COASTAL FLOOD ADVISORY IN EFFECT FROM 9 AM TO 11 AM PST THIS
MORNING...
...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM THIS EVENING
THROUGH SATURDAY AFTERNOON...

* WHAT...High astronomical tides will cause minor flooding in low
  lying areas. Up to one half foot of saltwater inundation above
  ground level is possible in low lying areas near shorelines and
  tidal waterways (up to 9.0 feet MLLW at the North Spit tide 
  gauge).

* WHERE...Northern Humboldt County coast, mainly around Humboldt 
  Bay, including Jackson Ranch Road and King Salmon.

* WHEN...For the Coastal Flood Advisory, from 9 AM to 11 AM PST
  this morning. 

* IMPACTS...Flooding of lots, parks, and roads with only isolated
  road closures expected.



PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Coastal Flood Advisory indicates that onshore winds and tides
will combine to generate flooding of low areas along the shore.

Feet Above Ground is locally defined as feet above the Highest
Astronomical Tide or HAT.

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$

CAZ101-104-109-202030-
/O.CON.KEKA.BH.S.0001.230121T0300Z-230122T0000Z/
Coastal Del Norte-Southwestern Humboldt-Mendocino Coast-
427 AM PST Fri Jan 20 2023

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM THIS EVENING
THROUGH SATURDAY AFTERNOON...

* WHAT...Increased risk for sneaker waves. There may be periods 
  of lulls in wave activity for up to 30 minutes before larger 
  sets of waves return.

* WHERE...Coastal Del Norte, Northern Humboldt Coast, 
  Southwestern Humboldt and Mendocino Coast Counties.

* WHEN...From this evening through Saturday afternoon.. .

* IMPACTS...Large, unexpected waves can sweep across the beach 
  without warning, sweeping people into the sea from rocks, 
  jetties, and beaches. These waves can also move large objects 
  such as logs, crushing anyone caught underneath.

* ADDITIONAL DETAILS...Sneaker waves occur when a larger set of 
  waves occurs after 20 to 30 minutes of smaller waves.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Don't be fooled by an ocean that looks calm. There can be 30 
minutes of small waves before a sneaker wave strikes. Avoid rocks 
and jetties. Avoid steep beaches. Stay much farther back from the 
water and never turn your back on the ocean.

&&

$$
962 
WHUS46 KEKA 201900
CFWEKA

Coastal Hazard Message
National Weather Service Eureka CA
1100 AM PST Fri Jan 20 2023

...Long Period Swell Moving in this Evening...

.Long period forerunners will start filling in this afternoon. 
The wave size will be sufficient for sneaker waves by this 
evening. The swell will be near 8 feet at 18 seconds by early 
Saturday morning. Steep beaches will have a higher risk of sneaker
wave activity with greater wave run-up onto beaches. Large waves 
will also wash over jetties and rock outcroppings that may 
normally stay dry.

CAZ103-210300-
/O.EXP.KEKA.CF.Y.0002.000000T0000Z-230120T1900Z/
/O.CON.KEKA.BH.S.0001.230121T0300Z-230122T0000Z/
Northern Humboldt Coast-
1100 AM PST Fri Jan 20 2023

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM 7 PM THIS 
EVENING THROUGH SATURDAY AFTERNOON...
...COASTAL FLOOD ADVISORY WILL EXPIRE AT 11 AM THIS MORNING...

* WHAT...Large unexpected waves along the coast.

* WHERE...Northern Humboldt Coast.

* WHEN...From 7 PM this evening through Saturday afternoon.

* IMPACTS...Large, unexpected waves can sweep across the beach 
  without warning, sweeping people into the sea from rocks, 
  jetties, and beaches. These waves can also move large objects 
  such as logs, crushing anyone caught underneath.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Don't be fooled by an ocean that looks calm. There can be 30 
minutes of small waves before a sneaker wave strikes. Avoid rocks 
and jetties. Avoid steep beaches. Stay much farther back from the 
water and never turn your back on the ocean.

$$

CAZ101-104-109-210300-
/O.CON.KEKA.BH.S.0001.230121T0300Z-230122T0000Z/
Coastal Del Norte-Southwestern Humboldt-Mendocino Coast-
1100 AM PST Fri Jan 20 2023

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT FROM 7 PM THIS 
EVENING THROUGH SATURDAY AFTERNOON...

* WHAT...Large unexpected waves along the coast.

* WHERE...Coastal Del Norte, Southwestern Humboldt, and Mendocino
  Coast.

* WHEN...From 7 PM this evening through Saturday afternoon.

* IMPACTS...Large, unexpected waves can sweep across the beach
  without warning, sweeping people into the sea from rocks,
  jetties, and beaches. These waves can also move large objects
  such as logs, crushing anyone caught underneath.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Don't be fooled by an ocean that looks calm. There can be 30 
minutes of small waves before a sneaker wave strikes. Avoid rocks 
and jetties. Avoid steep beaches. Stay much farther back from the 
water and never turn your back on the ocean.

$$
222 
WHUS46 KEKA 210259
CFWEKA

Coastal Hazard Message
National Weather Service Eureka CA
659 PM PST Fri Jan 20 2023

...Long Period Swell Moving in tonight and Saturday...

The swell will be near 8 feet at 18 seconds by early Saturday 
morning. Steep beaches will have a higher risk of sneaker wave 
activity with greater wave run-up onto beaches. Large waves will 
also wash over jetties and rock outcroppings that may normally 
stay dry.

Very high tides and large tidal swings are expected. This may
cause localized coastal flooding around Humboldt Bay.

CAZ103-211100-
/O.NEW.KEKA.CF.Y.0003.230121T1800Z-230121T2000Z/
/O.CON.KEKA.BH.S.0001.230121T0300Z-230122T0000Z/
Northern Humboldt Coast-
659 PM PST Fri Jan 20 2023

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH SATURDAY
AFTERNOON...
...COASTAL FLOOD ADVISORY IN EFFECT FROM 10 AM TO NOON PST
SATURDAY...

* WHAT...For the Coastal Flood Advisory, High astronomical tides
  will cause minor flooding in low lying areas along the Humboldt
  Coast. Up to one half foot of saltwater inundation above ground
  level is possible in low lying areas near shorelines and tidal
  waterways (Between 8.8 and 8.9 feet MLLW at the North Spit tide
  gauge). For the Beach Hazards Statement, large unexpected waves
  along the coast.

* WHERE...Northern Humboldt Coast County.

* WHEN...For the Coastal Flood Advisory, from 10 AM to noon PST
  Saturday. For the Beach Hazards Statement, through Saturday
  afternoon.

* IMPACTS...Flooding of lots, parks, and roads with only 
  isolated road closures expected. Large, unexpected waves can 
  sweep across the beach without warning, sweeping people into 
  the sea from rocks, jetties, and beaches. These waves can also 
  move large objects such as logs, crushing anyone caught 
  underneath.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Coastal Flood Advisory indicates that onshore winds and tides
will combine to generate flooding of low areas along the shore.

Feet Above Ground is locally defined as feet above the Highest
Astronomical Tide or HAT.

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$

CAZ101-104-109-211100-
/O.CON.KEKA.BH.S.0001.230121T0300Z-230122T0000Z/
Coastal Del Norte-Southwestern Humboldt-Mendocino Coast-
659 PM PST Fri Jan 20 2023

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

* WHAT...Large unexpected waves along the coast.

* WHERE...Coastal Del Norte, Southwestern Humboldt and Mendocino 
  Coast Counties.

* WHEN...Through Saturday afternoon.. .

* IMPACTS...Large, unexpected waves can sweep across the beach 
  without warning, sweeping people into the sea from rocks, 
  jetties, and beaches. These waves can also move large objects 
  such as logs, crushing anyone caught underneath.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$
858 
WHUS46 KEKA 211106
CFWEKA

Coastal Hazard Message
National Weather Service Eureka CA
306 AM PST Sat Jan 21 2023

...Long Period Swell Continues Saturday...

The swell is at 8 feet at 19 seconds early this morning, and will
be around 8 to 9 feet at 17 seconds by late morning as the sneaker
wave setup continues into the afternoon. Steep beaches will have 
a higher risk of sneaker wave activity with greater wave run- up 
onto beaches. Large waves will also wash over jetties and rock 
outcroppings that may normally stay dry.

Very high tides and large tidal swings are expected. This may
cause localized coastal flooding around Humboldt Bay.

CAZ103-211915-
/O.CON.KEKA.CF.Y.0003.230121T1800Z-230121T2000Z/
/O.CON.KEKA.BH.S.0001.000000T0000Z-230122T0000Z/
Northern Humboldt Coast-
306 AM PST Sat Jan 21 2023

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THIS
AFTERNOON...
...COASTAL FLOOD ADVISORY REMAINS IN EFFECT FROM 10 AM THIS
MORNING TO NOON PST TODAY...

* WHAT...For the Coastal Flood Advisory, High astronomical tides 
  will cause minor flooding in low lying areas along the 
  Humboldt Coast. Up to one half foot of saltwater inundation 
  above ground level is possible in low lying areas near 
  shorelines and tidal waterways (Between 8.8 and 8.9 feet MLLW 
  at the North Spit tide gauge). For the Beach Hazards 
  Statement, large unexpected waves along the coast.

* WHERE...Northern Humboldt Coast County.

* WHEN...For the Coastal Flood Advisory, from 10 AM to noon PST 
  Saturday. For the Beach Hazards Statement, through Saturday 
  afternoon.

* IMPACTS...Flooding of lots, parks, and roads with only 
  isolated road closures expected. Large, unexpected waves can 
  sweep across the beach without warning, sweeping people into 
  the sea from rocks, jetties, and beaches. These waves can also 
  move large objects such as logs, crushing anyone caught 
  underneath.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Coastal Flood Advisory indicates that onshore winds and tides
will combine to generate flooding of low areas along the shore.

Feet Above Ground is locally defined as feet above the Highest
Astronomical Tide or HAT.

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$

CAZ101-104-109-211915-
/O.CON.KEKA.BH.S.0001.000000T0000Z-230122T0000Z/
Coastal Del Norte-Southwestern Humboldt-Mendocino Coast-
306 AM PST Sat Jan 21 2023

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT THROUGH THIS
AFTERNOON...

* WHAT...Large unexpected waves along the coast.

* WHERE...Coastal Del Norte, Southwestern Humboldt and Mendocino 
  Coast Counties.

* WHEN...Through Saturday afternoon.. .

* IMPACTS...Large, unexpected waves can sweep across the beach 
  without warning, sweeping people into the sea from rocks, 
  jetties, and beaches. These waves can also move large objects 
  such as logs, crushing anyone caught underneath.



PRECAUTIONARY/PREPAREDNESS ACTIONS...

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$
011 
WHUS46 KEKA 211842
CFWEKA

Coastal Hazard Message
National Weather Service Eureka CA
1042 AM PST Sat Jan 21 2023

...Long Period Swell Continues Saturday...

The long period westerly swell is currently 10 feet at 17 seconds
as the sneaker wave setup continues into the afternoon. Steep 
beaches will have a higher risk of sneaker wave activity with 
greater wave run- up onto beaches. Large waves will also wash over
jetties and rock outcroppings that may normally stay dry.

Very high tides and large tidal swings are expected. This may
cause localized coastal flooding around Humboldt Bay.

CAZ103-220000-
/O.CON.KEKA.CF.Y.0003.000000T0000Z-230121T2000Z/
/O.CON.KEKA.BH.S.0001.000000T0000Z-230122T0000Z/
Northern Humboldt Coast-
1042 AM PST Sat Jan 21 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT UNTIL NOON PST
TODAY...
...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 4 PM PST THIS
AFTERNOON...

* WHAT...For the Coastal Flood Advisory, High astronomical tides 
  will cause minor flooding in low lying areas along the 
  Humboldt Coast. Up to one half foot of saltwater inundation 
  above ground level is possible in low lying areas near 
  shorelines and tidal waterways (Between 8.8 and 8.9 feet MLLW 
  at the North Spit tide gauge). For the Beach Hazards 
  Statement, large unexpected waves along the coast.

* WHERE...Northern Humboldt Coast County.

* WHEN...For the Coastal Flood Advisory, from 10 AM to noon PST 
  Saturday. For the Beach Hazards Statement, through Saturday 
  afternoon.

* IMPACTS...Flooding of lots, parks, and roads with only 
  isolated road closures expected. Large, unexpected waves can 
  sweep across the beach without warning, sweeping people into 
  the sea from rocks, jetties, and beaches. These waves can also 
  move large objects such as logs, crushing anyone caught 
  underneath.



PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Coastal Flood Advisory indicates that onshore winds and tides
will combine to generate flooding of low areas along the shore.

Feet Above Ground is locally defined as feet above the Highest
Astronomical Tide or HAT.

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$

CAZ101-104-109-220000-
/O.CON.KEKA.BH.S.0001.000000T0000Z-230122T0000Z/
Coastal Del Norte-Southwestern Humboldt-Mendocino Coast-
1042 AM PST Sat Jan 21 2023

...BEACH HAZARDS STATEMENT REMAINS IN EFFECT UNTIL 4 PM PST THIS
AFTERNOON...

* WHAT...Large unexpected waves along the coast.

* WHERE...Coastal Del Norte, Southwestern Humboldt and Mendocino 
  Coast Counties.

* WHEN...Through Saturday afternoon.. .

* IMPACTS...Large, unexpected waves can sweep across the beach 
  without warning, sweeping people into the sea from rocks, 
  jetties, and beaches. These waves can also move large objects 
  such as logs, crushing anyone caught underneath.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$
637 
WHUS46 KEKA 212242
CFWEKA

Coastal Hazard Message
National Weather Service Eureka CA
242 PM PST Sat Jan 21 2023

...Long Period Swell Continues Saturday Evening...

The long period westerly swell is currently 10 feet at 17 seconds
as the sneaker wave setup continues into the afternoon. Steep
beaches will have a higher risk of sneaker wave activity with
greater wave run- up onto beaches. Large waves will also wash
over jetties and rock outcroppings that may normally stay dry.

Very high tides and large tidal swings are expected. This may
cause localized coastal flooding around Humboldt Bay.

CAZ103-220645-
/O.NEW.KEKA.CF.Y.0004.230122T1800Z-230122T2200Z/
/O.EXT.KEKA.BH.S.0001.000000T0000Z-230122T0500Z/
Northern Humboldt Coast-
242 PM PST Sat Jan 21 2023

...BEACH HAZARDS STATEMENT NOW IN EFFECT UNTIL 9 PM PST THIS
EVENING...
...COASTAL FLOOD ADVISORY IN EFFECT FROM 10 AM TO 2 PM PST
SUNDAY...

* WHAT...For the Coastal Flood Advisory, High astronomical tides
  will cause minor flooding in low lying areas along the Humboldt
  Coast. Up to one half foot of saltwater inundation above ground
  level is possible in low lying areas near shorelines and tidal
  waterways (Between 8.7 and 8.8 feet MLLW at the North Spit tide
  gauge). For the Beach Hazards Statement, large unexpected waves
  along the coast.

* WHERE...Northern Humboldt Coast County.

* WHEN...For the Coastal Flood Advisory, from 10 AM to 2 PM PST 
  Sunday. For the Beach Hazards Statement, until 9 PM PST this 
  evening.. .

* IMPACTS...Flooding of lots, parks, and roads with only 
  isolated road closures expected. Large, unexpected waves can 
  sweep across the beach without warning, sweeping people into 
  the sea from rocks, jetties, and beaches. These waves can also 
  move large objects such as logs, crushing anyone caught 
  underneath.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Coastal Flood Advisory indicates that onshore winds and tides
will combine to generate flooding of low areas along the shore.

Feet Above Ground is locally defined as feet above the Highest
Astronomical Tide or HAT.

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$

CAZ101-104-109-220500-
/O.EXT.KEKA.BH.S.0001.000000T0000Z-230122T0500Z/
Coastal Del Norte-Southwestern Humboldt-Mendocino Coast-
242 PM PST Sat Jan 21 2023

...BEACH HAZARDS STATEMENT NOW IN EFFECT UNTIL 9 PM PST THIS
EVENING...

* WHAT...Large unexpected waves along the coast.

* WHERE...Coastal Del Norte, Southwestern Humboldt and Mendocino 
  Coast Counties.

* WHEN...Until 9 PM PST this evening.. .

* IMPACTS...Large, unexpected waves can sweep across the beach 
  without warning, sweeping people into the sea from rocks, 
  jetties, and beaches. These waves can also move large objects 
  such as logs, crushing anyone caught underneath.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Don't be fooled by an ocean that looks calm.  There can be
30 minutes of small waves before a sneaker wave strikes.  Avoid
rocks and jetties. Avoid steep beaches.  Stay much farther back
from the water and never turn your back on the ocean.

&&

$$
834 
WHUS46 KEKA 220447
CFWEKA

Coastal Hazard Message
National Weather Service Eureka CA
847 PM PST Sat Jan 21 2023

CAZ103-221300-
/O.EXP.KEKA.BH.S.0001.000000T0000Z-230122T0500Z/
/O.CON.KEKA.CF.Y.0004.230122T1800Z-230122T2200Z/
Northern Humboldt Coast-
847 PM PST Sat Jan 21 2023

...COASTAL FLOOD ADVISORY REMAINS IN EFFECT FROM 10 AM TO 2 PM
PST SUNDAY...

* WHAT...High astronomical tides will cause minor flooding in low
  lying areas along the Redwood Coast. Up to one half foot of
  saltwater inundation above ground level is possible in low lying
  areas near shorelines and tidal waterways (Between 8.8 and
  8.9feet MLLW at the North spit tide gauge).

* WHERE...Northern Humboldt Coast County.

* WHEN...From 10 AM to 2 PM PST Sunday.. .

* IMPACTS...Flooding of lots, parks, and roads with only 
  isolated road closures expected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Coastal Flood Advisory indicates that onshore winds and tides
will combine to generate flooding of low areas along the shore.

Feet Above Ground is locally defined as feet above the Highest
Astronomical Tide or HAT.

&&

$$

CAZ101-104-109-220600-
/O.EXP.KEKA.BH.S.0001.000000T0000Z-230122T0500Z/
Coastal Del Norte-Southwestern Humboldt-Mendocino Coast-
847 PM PST Sat Jan 21 2023

...BEACH HAZARDS STATEMENT WILL EXPIRE AT 9 PM PST THIS EVENING...

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 20, 3:04 AM PSTSmall Craft AdvisoryEKA4 hr
Jan 20, 4:27 AM PSTCoastal Flood AdvisoryEKAHumboldt7 hr

Nearby

Beach Hazards Statements in California, 2023Every beach hazards statement 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.