Monday, April 06, 2009

Alaskan Bore Tides

Map of Cook Inlet and Turnagain Arm, AlaskaAlaska has all sorts of strange things happening. Besides the errant volcano or earthquake here in Anchorage we get what are called "bore tides."

A tidal bore occurs when you have a large body or bay of water (such as Cook Inlet, which you can see on the map here) and smaller inlets such as Turnagain Arm (also seen on the map in smaller letters south of Anchorage).

Instead of the tide coming in gradually like it does in other self-respecting places the enormous tides here push the water so quickly up the inlet and down into Turnagain Arm that it gets squeezed through the narrowing gap between the mountains and forms a wall of water 10-12 feet high. As it moves up the Arm and on toward the town of Portage southwest of Anchorage the water can reach speeds of up to 10-12 knots (which is roughly about 10-12 miles per hour. Roughly).

Bore tides aren't really what you'd call a rare occurrence, from what I understand there are about 60 different places around the world where they can form but what makes Anchorage's bore tides different is that first, the tidal variance here is so large (27 feet) that the show becomes pretty spectacular. Second, mountains surround Turnagain arm right down to the water's edge making for a beautiful backdrop. Third, you don't see bore tides very often in the north, let alone this far north and fourth, this particular tidal bore is easily accessible so anyone can see it.

Cook Inlet AlaskaThe Seward Highway runs southwest from Anchorage along Turnagain Arm down past Portage and besides the beluga and humpback whales you can see the bore tides from your car as you zip along--if you happen to hit the right time of day.

They're best seen right around the new or the full moon, they're better in the spring and fall around each equinox, and of course they're better right after an extreme low tide.

While the water in Cook Inlet is usually just above freezing it's not uncommon to see crazies out there surfing (my own uncle, a California transplant, used to don his dry suit and head out there from time to time). It's definitely not for the novice surfer because besides the water being a lethal temperature it's very silty and perfect for dragging you down. Then of course the tides and currents can kill you and then there aren't any soft sandy beaches on which to land should you get thrown around a bit--nothing but jagged rocks where the mountains meet the water.

It just seems to me that there are so many better ways to die than frozen to a surf board in Alaska as an h'ors d'oeuvre for a wandering beluga (Kidding! At least about the beluga part--they don't eat humans, just salmon).

So here's a clip of what the bore tides look like, including some surfer showing off his stuff.



Just one more strange yet interesting thing about living here.

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18 comments:

Michemily said...

Wow, like you said: strange but interesting.

Jolanthe said...

That's really neat (in an odd sort of way!). ;) and I don't understand crazy people surfing in cold, cold water....brrrrrr!

Lucy said...

I'd love to live in Alaska for a while to see it all. I've never been there and probably won't get to but possiblities are slim. What a beautiful state. And...surfing?

Annette Lyon said...

Cool! I'd never ever heard of bore tides before. Loved that video.

Summer said...

I'd heard of bore tides but didn't actually know what they were. That's a neat video and beautiful scenery.

I don't understand the desire to surf in the first place (not knowing what's in the water right beneath me is freaky) but surfing in icy water is doubly crazy!

Carolyn V. said...

It is beautiful! But I must admit...I was cold just watching that person on the water!

Maddy said...

Fabulous! Takes me back to O'Level geography but a video is so much better than a still.
Cheers

Jill in MA said...

Very cool! Thanks for educating us! I went to Alaska once and I'd love to go back. It is one of those places that's so beautiful, pictures don't do it justice.

jacjewelry said...

It must be a magnificent sight! Will watch the video when I get home, but the picture you posted is breathtaking, so I can only imagine how much better it looks in person.

thechickadeefeeder said...

This is extremely interesting; I've always wondered about this, but never knew what it was called, etc. One of my favorite books--The Wheel on the School by DeJong--has the tide coming in so fast (in Holland)and I never really understood it.

Carissa(GoodnCrazy) said...

You know those sleeping music CDs? Your video could be one of those.. I love that sound! I just wish they could add the smell of the ocean as well as the noise, ha!

Never heard of Bore Tides before.. now I'll sound so smart at the next cocktail party.... :)

Kelly @ Love Well said...

That is totally fascinating. Props to the surfer; that's dedication.

Janet said...

Cool - I don't think I'd be surfing though. I'm sending the link to my BIL in case they missed one of these while they were in Alaska.
Around here the only tidal bores we get are the people who love to hear themselves talk and never have anything to say.

Suzie B. said...

It looks like a scary place to be in a boat when that's happening, let alone on a surf board! Does the water seep back slowly to low tide?

Chrissy Johnson said...

That rules on so many levels! That's my favorite stretch of highway in the world, btw.

Kathryn said...

I love watching the bore tides! I have only seen a few and none have been as cool as the ones in that video! My favorite place to watch is that beach past Beluga Point. (Except it's been banned so people don't cross the train tracks!)

JENNIFER said...

things like that fascinate me...thanks for sharing all about it.

Jennifer said...

They sound so cool, but I gotta admit, I was hoping for a little more destructive 10' wave action in the video. :)

I went snorkeling in Alaska, but that isn't as crazy as surfing in Alaska.