Archive for the 'tsunami' Category

Tidal wave

January 18, 2007

severn bore
Images by Chris Witts from here

The old “tidal wave” word is now best described as a tidal bore (save confusin with tsunamis). There is a Severn Bore which can be surfed check out the Bore Riders Club

“When the boar comes, the stream does not swell by degrees, as at other times, but rolls in with a head…foaming and roaring as though it were enraged by the opposition which it encounter”

Thomas Harrel 1824

 curling bore wave

Also from the Severn Bore site:

The Severn Bore is one of Britain’s few truly spectacular natural phenomena. It is a large surge wave that can be seen in the estuary of the River Severn, where the tidal range is the 2nd highest in the world, being as much as 50 feet (approx. 15.4m).

As many as 60 bores occur throughout the world where the river estuary is the right shape and the tidal conditions are such that the wave is able to form. The Severn Bore (one of 8 in the UK) is one of the biggest in the world but bores also occur on the Seine and Gironde in France, on the Indus, Hooghly and Brahmaputra in India, on the Amazon in Brazil, on the Petitcodiac, New Brunswick, and also the Knik Arm bore at the head of Cook Inlet, Alaska.

By far the biggest bore in the World is the Ch’ient’ang’kian (Hang-chou-fe) in China. At spring tides the wave attains a height of up to 25 ft (7.5 m) and a speed of 13-15 knots (24-27 km/h). It is heard advancing at a range of 14 miles (22 km).

watch a clip of the chinese tidal wave bursting over the water defences

Tsunami warning 13 January

January 15, 2007

There was a small tsunami, I think the biggest wave was 0.4m in Chijima one of islands  south of Tokyo, on Saturday afternoon. The earth quake which caased it was very big: 8.3 epicenter in the sea between Hokkaido and Russia.

quake
13janmap

0.2m at Miyako where I paddled along the Iwate Coast. Not sure what happend in Miyagi. The BBC story

Kayakers survive the tsunami

December 12, 2006

Okay, I know I’m late (and thanks to the guys at seapaddler.co.uk) but here is the story of Bob Kadiko

IT WAS THE DAY AFTER Christmas, and Bob Kandiko ’76 [class of 76 at Cornell University] and his wife and niece were kayaking the calm, teal waters off the island of Rawi in Thailand. They had been looking for a place to have lunch when they came upon the perfect spot–a gorgeous cove with a white-sand beach. But one thing struck Kandiko as strange: the ocean had receded so far that it had exposed the jagged coral seafloor– at high tide.

Kandiko, a middle-school science teacher from Bellingham, Washington, knew that an empty bay at high tide meant that a massive force had displaced a large amount of water, and quickly. And he knew that meant a tsunami.

As the kayakers watched, a four-meter-high wave rushed in, parallel to the shore, and filled the entire bay and beach in fifteen seconds. “Half of a football field is what we were looking at,” Kandiko says. The wave circled back and collided with itself like water in a giant blender, creating a swell that lifted the eighteen-foot kayaks and shoved them away from shore. “Right after that happened,” says his niece, Camille Kandiko ’02 [class of 2002 at Cornell], “my uncle screamed at us to paddle out to the ocean–fast.”

Kandiko knew that they’d be safest in deep water, where the tsunami would be a massive but navigable ocean swell; it breaks into a wave only as it nears land, he says. “And my comment was, ‘If it’s a tsunami, there’s going to be more coming.’ ” Sure enough, fifteen minutes later another wave–twice as big as the first–surged along the coast and crashed into the jungle, ripping up trees and churning the clear water to dark brown. “That’s when we started to get creeped out,” Camille says, “because we realized that had we been in there, we never would have survived.”

They made it to shore several exhausting hours later, but it would be days before they reached the mainland and discovered that the tsunami had left hundreds of thousands missing or dead throughout Southeast Asia.

from here

Intersting stuff. First that they survived at all (though from a quick google search Bob appears to be an experienced kayaker) and second that the kayaks didn’t seem that disturbed by the big waves. Maybe I’ll be okay if a tsunami hits in Japan after all.

Sea Kayaking book

November 22, 2006

There is a new book out by Scottish sea kayaker Gordon Brown, (of Skyak adventures fame). The Title is “Sea Kayak” with a tag line of “A manual for intermediate and advanced sea kayakers”.

Despite the unimaginative title it looks pretty good. You can download two chapters from the publishers website

skc

On page 1 of chapter 15 “Swell” he answers my question about what to do in the case of a tsunami.

Other phenomena that cause swell are earthquakes, massive landslips and meteorite impacts, each of which may generate tsunami (tidal waves). The power of a tsunami can be truly awesome as observed in the Indian Ocean, December 2004. Caused by an underwater earthquake, the resulting surface wave was only a few centimetres high, but the wave was
full-depth, that is its effect went from the surface to the ocean floor. When it came close to land the first indication was that the water drained from beaches and reefs only to be replaced by a very much larger lump of sea. If you are on the water when a tsunami occurs, the best option for your survival is to turn out to sea and paddle as if your life depended on it, because it probably does.

He has a definition on wave height which answers my question:

Wave height is the vertical distance from trough to peak of a wave.

The pictures also look great (poor resolution here) this one of clapotis (caused by wave interaction)

clapotis

I’m definately getting this book, not least as it is written by a Scottish sea kayaker and I imagine I won’t have to interpret the advice as much as I had to with the other books on sea kayaking I have read.

Out on December 7th from Paseda press.

Tsunami warning last night

November 16, 2006

There was a tsunami warning last night after a 8.1 magnitude earthquake in the Kuril Islands, north east of Japan. (image from the bbc story)

frombbc
This has now made my wife very nervous about me going kayaking…

here is the map from the JMA:

warning

Personally I am less worried about tsunamis although I do wonder.

They are also advising of gale force storm building of the Iwate Coast. Looks like short lived though…
ww

and the text:

11:28 JST 11/16/2006
SENDAI WX
160900JST ISSUED AT 161130JST

GALE WARNING FOR SEA OFF SANRIKU

DEVELOPING LOW 1010HPA AT 43N 144E MOVING ENE 30KT
WARM FRONT FROM 43N 144E TO 43N 146E 43N 149E
COLD FRONT FROM 43N 144E TO 40N 144E 37N 142E 34N 140E
LOW 1012HPA AT 37N 147E MOVING ENE 20KT

IN SEA OFF SANRIKU
NW-LY WINDS WILL INCREASE TO MAX 35KT FOR NEXT 6 HOURS

WARNING VALID 170900JST