In article <2e60a49f-5da4-4056-998c-7068ebf5b3d8
@
b9g2000pba.googlegroups.com>,
tut...@hotmail.com says...
>
> On Oct 30, 11:06Â pm, Mark Borgerson <
mborger...@comcast.net> wrote:
>
> > LOL! Â "The west coast (coastal waters) doesn't see much in the way
> > of heavy seas". Â Â Why do you think the US Coast Guard does
> > motor lifeboat training off the mouth of the Columbia River
> > between Oregon and Washington?
>
>
> Because of the tides and currents?
Nope. Because of the high surf in the region of the Columbia
River bar. A search for "coast guard motor lifeboat school" will
find you some interesting videos of the wave action off the
Washington coast. You get lots of nice breaking waves when
an outgoing tide meets a 15-foot swell.
>
>
> > The West Coast of the US often has wind waves and swells that
> > match or exceed anything off the US East or Gulf coasts. Â After all,
>
> Wind waves and swells. Not storms, hurricanes or typhoons though.
> Storm season is relatively short.
The maximum wave heights off the west coast occur between October
and April. (See Allan and Komar paper cited later). That's about the
same duration as the storm season off the East Coast.
>
> We see plenty of "small boat advisories" sure. And the Venus, due to
> her design would not do as well as one of her size should. But, those
> shouldn't be dangerous for her either.
>
Try a google search for "farallon islands shipwrecks". The area
just outside San Francisco Bay is pretty dangerous. In my younger
and more foolish days (26 and just out of the Navy), I singlehanded
a 24-foot sailboat from Oakland out the Golden Gate and up
to Bodega Bay. The combination of fog, seas, rocks and
other hazards made that a very interesting trip. On the way
back, I got caught in the ebb tide----it took me about 7
hours to make the last 12NM to Angel Island.
>
> > A few weeks ago I spent a week up in Alaska helping people
>
> I specifically excluded Alaska.
I must have missed that. All I see is "the west coast (coastal
waters). Alaska up to about Seward is a West-facing coast
and is part of the US. However, a study, cited later,
shows that the largest waves occur off the Washington
Coast. Alaska, Oregon and California generally have
smaller wave heights.
>
>
> > If you still doubt that the West Coast has heavy seas,
> > go see the movie "Chasing Mavericks"
>
> That's about a big wave surfing contest you know. Last one was live
> streamed btw.
> A localized wave due to an underwater formation speaks about sea
> state. Really?
No swell, no big surf, no matter what the underwater configuration.
Incidentally, when discussing waves, particularly off the West
coast, it's helpful to distinguish between localized wind wave
height and the swell. The swell can have heights around
30 feet and a period in the range of 11 to 14 seconds.
Wind waves are generally a fraction of that height and have
periods around 3 to 5 seconds.
>
> I've been out in that water. And the Mavericks big wave contest can be
> fun. The local pier is great for certain seasonal fresh fish and crab.
> Good little restaraunt shack too.
>
> Maybe I need to be more specific: dangerously heavy, as seen off the
> east coast this week.
http://gcaptain.com/sandy-wave-height-analysis/
shows the peak wave heights for Sandy to be 43 to 47 feet, as
measured by NOAA buoys. However that is from a buoy that
is anchored in only 28m of water. With water that shallow,
the larger waves are probably already starting to feel
the bottom and pile up. Note that the wave height today
is down to about 5 ft, so things have calmed down
pretty quickly as Sandy moved onshore.
Off the coast of Washington:
Big waves along Washington's coast
"High energy
The Pacific Northwest coast has one of the highest wave energy levels in
the world. Wave heights on average are large.
Big storm waves
Winter storms can generate waves more than 22.8 feet (7 meters) high. An
intense winter storm during the 1997/98 El Niño produced waves 48 feet
high.
Getting bigger
Between 1975 and 1999, the largest storm waves off the coast of
Washington increased in height from 26 feet (8 meters) to 39 feet (12
meters). What's causing the increase? El Niño may be a factor.
The biggest
Extreme waves 50 to 90 feet in height have been recorded on and beyond
the continental shelf. "
http://www.ecy.wa.gov/programs/sea/coast/waves/big_waves.html
Off the East coast, wave heigts are also increasing:
"Significant wave heights measured during the hurricane season (which
runs from June 1 to November 30) show that the most extreme occurrences
during the 1996 to 2005 decade were both higher and more common than
those of 30 years ago, having increased from about 23 feet (7 meters) to
higher than 33 feet (10 meters). Hurricane season peaks in late August
to early September. "
So the big waves went up to 10m or more on the East Coast and
12m or more on the West coast. Note that the reports cover two
different time periods, with the East coast data being more recent.
http://www.livescience.com/4867-ocean-wave-heights-rising-east-
coast.html
For a more general explanation see:
http://science.howstuffworks.com/environmental/earth/oceanography/questi
on623.htm
The high wave energy is one of the reasons that they are building the
first large prototype wave energy facility off Coos Bay, Oregon.
For an in-depth study, you might also take a look at this report by
Allan and Komar:
http://www.oregon.gov/LCD/OCMP/docs/publications/wave_climate_rpt.pdf
This is a report by two oceanography professors at the College of
Oceanic and Atmospheric Sciences at Oregon State University.
(disclaimer: I am a Faculty Research Assistant in physical
oceanography at OSU--but was not employed there when the
report was written.)
Mark Borgerson