Are west facing beaches better for surfing?

[Jennifer Murphy]

A Trivial Pursuit card came up the other say that asked,

What direction do the best surfing beaches face?

The answer was

West

I did a quick Internet search and could not find anything to support
this.

Is it true?

If so, why?

[Thomas]

On Fri, 08 Mar 2013 18:06:40 -0800, Jennifer Murphy <JenM...@jm.invalid>
wrote:

Yes.

> If so, why?

The way the Earth spins on its axis, plate tectonics, and chance.

Winds cause waves. Predominate winds blow west to east. Plate tectonics
has tended to make the eastern side of the continents shallower, which
creates drag on waves, lessening their power and size.

[Jennifer Murphy]

I've been doing a little more research. I discovered that, as you say,
winds tend to blow west to east and winds are a major factor in creating
waves. So they would tend to increase waves on west-facing beaches and
decrease them on east-facing beaches.

I hadn't come across the point about the continental shelf. There's a
little map on Wikipedia that shows the size of the continental shelf
everywhere in the world:

http://en.wikipedia.org/wiki/Continental_shelf
http://en.wikipedia.org/wiki/File:Elevation.jpg

In North America, the shelf is much wider on the east coast than the
west.

The same is true for South America except for the southern part of the
west coast and the eastern-most part of Brazil.

For Africa, it's the opposite. This would make sense if the continents
are moving apart, as geologists say.

Using that logic, Australia must be moving southeast.

Islands, like Hawaii, probably benefit from both little or no shelf and
winds that have nothing (mouintains) to slow them down.

Does that square with where the best surfing beachers are:

west coast of US
west coast of northern 2/3 of South America
eastern-most part of Brazil
east coast of Africa
south and east coasts of Australia
any coast of islands (west better because of winds)

Thanks

[Jennifer Murphy]

On Fri, 08 Mar 2013 18:46:26 -0800, Thomas <xs...@xmail.com> wrote:

I just found an interesting Wikipedia article:

http://en.wikipedia.org/wiki/Ocean_surface_wave

The great majority of large breakers one observes on a beach result from
distant winds. Five factors influence the formation of wind waves:

1 Wind speed
2 Distance of open water that the wind has blown over
(called the fetch)
3 Width of area affected by fetch
4 Time duration the wind has blown over a given area
5 Water depth

[Kev]

Jennifer Murphy <JenM...@jm.invalid> writes:
>
> Does that square with where the best surfing beachers are:

> ...

> south and east coasts of Australia

The conventional wisdom is south and west get more size but something
about the west being geologically younger or older or something that it
doesn't have as much beaches and points as the east.




--
We are extremely excited about making the sequel to a movie that was
well received and highly regarded by audiences all around the world.
-- Studio Bosses commenting on rumours about "Point Break II" (ASL Sep 2007)

[Tony M]

"Jennifer Murphy" wrote:
> I've been doing a little more research. I discovered that, as you say,
> winds tend to blow west to east and winds are a major factor in creating
> waves.
>

When it comes to surfable waves, wind is the only factor.

> I hadn't come across the point about the continental shelf. There's a
> little map on Wikipedia that shows the size of the continental shelf
> everywhere in the world:
>

> In North America, the shelf is much wider on the east coast than the
> west.
>

This is due to the fact that the East coast is much older, geologically
speaking.
The West coast of the US is fairly new in geological time, so the shelf is
narrow
with a lot more slope.

> Islands, like Hawaii, probably benefit from both little or no shelf and
> winds that have nothing (mouintains) to slow them down.
>

Local winds have little to no effect on waves, other than creating surface
texture.
For instance, the big surf that hits Hawaii's Northern shores in Winter is
created by storms
up near the Aleutian Islands.
Conversely, some of the biggest surf in Southern California is generated by
storms near
New Zealand.

The main reason that Western shores of most continents get larger more
consistent surf
is because most storm systems move from West to East and the swell they
generate travels
roughly in the same direction.

[Tony M]

"Jennifer Murphy" wrote:
> The great majority of large breakers one observes on a beach result from
> distant winds. Five factors influence the formation of wind waves:
>
> 1 Wind speed
> 2 Distance of open water that the wind has blown over
> (called the fetch)
> 3 Width of area affected by fetch
> 4 Time duration the wind has blown over a given area
> 5 Water depth

The three critical factors in wave generation are
Velocity - Speed of the wind
Fetch - distance that same wind blows over a given stretch of water
Duration - The length of time that same wind blows at the given speed over
the same fetch.

Water depth is directly related to the property known as wave length.
This is the distance between the crests of two successive waves. Length is a
reflection of
the energy a wave has accumulated. It can also be expressed as wave period.
Period is
the time it takes two successive waves to pass a fixed point. As period
increases, so does wavelength.
A deep water wave is defined as one whose length is more than double the
water depth. A shallow water
wave is one that has entered a depth that's one half the wavelength, or
less. All of these properties can be
determined if you know the wave period. A wave with a 10 second period has a
length of 512 ft in deep
water. Once it enters water of 256 ft or less, it is defined as a shallow
water wave. At that point, the
length becomes shorter, the forward velocity slows down, and the height will
diminish ....but the period
remains constant.
Don't take everything you read on Wikipedia as "gospell". The info there is
reader contributed and no one
really edits it from a scientific standpoint most of the time.
Me? I've been surfing for 50 years and have studied wave science for almost
as long. My info comes from
scientists and their work is based in oceanography and physics.

--
Tony M

[Tony M]

"Kev" wrote:
> The conventional wisdom is south and west get more size but something
> about the west being geologically younger or older or something that it
> doesn't have as much beaches and points as the east.
>

This may be true in OZ, but the US West Coast has far more points
mainly due to the lack of continental shelf and geological 'youth'.
The East coast of North America hasn't a single true point break
South of Long Island. It is all beach break clear down to Florida,
where there are a few scattered reefs among the endless miles of
beachbreaks.
Plenty of points North of there, though....all the way up into Canada.

--
Tony M

[Thomas]

On Tue, 12 Mar 2013 16:09:49 -0700, Tony M <to...@noway.net> wrote:


> Local winds have little to no effect on waves, other than creating
> surface texture.

That's not really true. We all crave ground swells from half a planet away
and dread local winds that destroy good shape, but there are many places
where a good wind swell with a relatively short fetch creates fun waves.
The Great Lakes and the Mediterranean are two examples.

[Thomas]

On Sat, 09 Mar 2013 07:43:05 -0800, Jennifer Murphy <JenM...@jm.invalid>
wrote:

>
> Does that square with where the best surfing beaches are:

>
> west coast of US
> west coast of northern 2/3 of South America
> eastern-most part of Brazil
> east coast of Africa
> south and east coasts of Australia
> any coast of islands (west better because of winds)
>
> Thanks

The most ferocious storms are near the poles, so any coasts exposed to
those storms will get surf. I was a little misleading when I wrote that
global wind patterns move west to east. That's the direction that creates
the best waves in many of the places surfers congregate. The winds that
move east to west often create hurricanes, which can produce great surf,
but they're more sporadic. Here's a map showing the predominate wind
currents:
http://people.hofstra.edu/geotrans/eng/ch1en/conc1en/img/windpatterns.gif

Your list is fairly accurate, but you've left out the Indian ocean, which
creates good waves for Indonesia and south-west Australia. Also, the west
coast of Europe gets good waves.
As for Africa - south-east Africa gets better surf than north-east Africa,
but south-west Africa also gets good waves. North-west Africa is exposed
to the North Atlantic winter swells, but anywhere in the Bight is not
nearly as good, mainly because of shallow water.

HTH.

[Tony M]

"Thomas" wrote:

> Tony M wrote:
>> Local winds have little to no effect on waves, other than creating
>> surface texture.
>
> That's not really true.

In the context of my reply to the OP, it certainly is. She seems to think
that
local topography will affect winds in the generation of waves. I pointed out
that
it is not the case. Even a half-assed wind swell needs a decent fetch of
open water
to get rolling. I know this. I live on the EC USA, where 90% of our ridable
waves
come from windswell under 12 seconds.

> there are many places where a good wind swell with a relatively short
> fetch creates fun waves. The Great Lakes and the Mediterranean are two
> examples.
>

The med apparently gets good from time to time. The Great Lakes are
anything but "great" . As I said, I'm an East Coaster, and even I consider
the GLs
a joke.