OT - 100 ft. Rogue Waves

[ricki]

Just came across this and just in time for wave riding season ...

http://www.towsurfer.com/Content/00026/pic1.jpg
Large cargo ship approaches a rogue wave : image courtesy BBC Horizon, Freak Waves.

Reposted from: http://www.towsurfer.com/ViewArticle.asp?ContentID=26

100' Rogue Waves

Experts Baffled by Giant Walls Of Water

Surfersvillage Global Surf News, 24 October 2004: - - Rogue waves are the stuff of legend and maritime myth: Giant waves, taller than highrise buildings, that rise out of calm seas. For years scientists and marine experts have dismissed such stories as superstition.

Walls of water do not rise out of the blue, they said. But now research has revealed that 'killer waves' do exist and regularly devastate ships around the world. They defy all scientific understanding and no craft is capable of withstanding their impact.

Rogue waves in the past have been ignored and regarded as rare events, now we are finally getting a handle on them and finding out how common they are. These mammoth events are not tidal waves or tsunamis, however. Nor are they caused by earthquakes or landslides. They are single, massive walls of water that rise up - for no known reason - and destroy dozens of ships and oil rigs every year.

The story of the super-tanker Munchen is a classic example. She was one of the biggest ships ever built - the length of two-and-a-half football pitches - and unsinkable, it was claimed. But on 7 December, 1978, the pride of the German merchant navy, en route to America, disappeared off the face of the earth. All that was found of the Munchen and her 26 crew was a lifeboat that had suffered an incredible battering.

Something extraordinary had destroyed the ship, concluded an official inquiry, which dismissed the Munchen's sinking as a highly unusual event that had no implications for other forms of shipping. Now scientists believe this calm assurance may be dangerously misguided. The destruction of the Munchen was anything but uncommon. Ships are going down all the time. If you read the maritime press there is a boat going down at least once a month, with the loss of crew usually measured in dozens of lives. In the past, bad maintenance or poor seamanship were blamed. Now scientists suspect the truth may be more bizarre.

It is known that the Queen Mary was hit by a 75ft wall of water while carrying 15,000 troops in December 1942. The ship came within an ace of capsizing. Only a few years ago the British superliner Oriana was struck by a 70ft wave that smashed windows and sent water cascading through the ship, swamping six of its 10 decks.

These giant waves cannot be predicted by standard meteorology. Waves - even in the worst of storms - should not reach much more than 40ft. The fact that walls of water up to 100ft are being observed regularly suggests that something is worryingly wrong with meteorology theory.

Waves are normally caused by high winds whipping over the sea surface, but the origin of the freak waves baffles scientists. One theory suggests that waves and winds heading straight into powerful ocean currents may cause these huge walls of water to rise up out of the deep. Another suggests that, under certain conditions, waves can become unstable and start to suck in energy from neighbouring waves and so grow massively and rapidly.

Researchers are still arguing over these ideas, but what is indisputable is the fact that the design of modern ships is inadequate for dealing with the freak waves.
-- SurfersVillage.com

[ricki]

Just came across this and just in time for wave riding season ...

http://www.towsurfer.com/Content/00026/pic1.jpg
Large cargo ship approaches a rogue wave : image courtesy BBC Horizon, Freak Waves.

Reposted from: http://www.towsurfer.com/ViewArticle.asp?ContentID=26

100' Rogue Waves

Experts Baffled by Giant Walls Of Water

Surfersvillage Global Surf News, 24 October 2004: - - Rogue waves are the stuff of legend and maritime myth: Giant waves, taller than highrise buildings, that rise out of calm seas. For years scientists and marine experts have dismissed such stories as superstition.

Walls of water do not rise out of the blue, they said. But now research has revealed that 'killer waves' do exist and regularly devastate ships around the world. They defy all scientific understanding and no craft is capable of withstanding their impact.

Rogue waves in the past have been ignored and regarded as rare events, now we are finally getting a handle on them and finding out how common they are. These mammoth events are not tidal waves or tsunamis, however. Nor are they caused by earthquakes or landslides. They are single, massive walls of water that rise up - for no known reason - and destroy dozens of ships and oil rigs every year.

The story of the super-tanker Munchen is a classic example. She was one of the biggest ships ever built - the length of two-and-a-half football pitches - and unsinkable, it was claimed. But on 7 December, 1978, the pride of the German merchant navy, en route to America, disappeared off the face of the earth. All that was found of the Munchen and her 26 crew was a lifeboat that had suffered an incredible battering.

Something extraordinary had destroyed the ship, concluded an official inquiry, which dismissed the Munchen's sinking as a highly unusual event that had no implications for other forms of shipping. Now scientists believe this calm assurance may be dangerously misguided. The destruction of the Munchen was anything but uncommon. Ships are going down all the time. If you read the maritime press there is a boat going down at least once a month, with the loss of crew usually measured in dozens of lives. In the past, bad maintenance or poor seamanship were blamed. Now scientists suspect the truth may be more bizarre.

It is known that the Queen Mary was hit by a 75ft wall of water while carrying 15,000 troops in December 1942. The ship came within an ace of capsizing. Only a few years ago the British superliner Oriana was struck by a 70ft wave that smashed windows and sent water cascading through the ship, swamping six of its 10 decks.

These giant waves cannot be predicted by standard meteorology. Waves - even in the worst of storms - should not reach much more than 40ft. The fact that walls of water up to 100ft are being observed regularly suggests that something is worryingly wrong with meteorology theory.

Waves are normally caused by high winds whipping over the sea surface, but the origin of the freak waves baffles scientists. One theory suggests that waves and winds heading straight into powerful ocean currents may cause these huge walls of water to rise up out of the deep. Another suggests that, under certain conditions, waves can become unstable and start to suck in energy from neighbouring waves and so grow massively and rapidly.

Researchers are still arguing over these ideas, but what is indisputable is the fact that the design of modern ships is inadequate for dealing with the freak waves.
-- SurfersVillage.com

[ricki]

Looking into this a bit more I came across ...

'h. Rogue waves are very rare large waves, probably due to unusual constructive wave interference. They are most frequent downwind from islands or shoals or where storm waves move against strong ocean currents, such as the Agulhas current off the southeastern coast of Africa. Rogue waves may sink or damage ships and often wash fishermen off rocks. Storm waves can often combine to produce waves as large as a 7-8 story building or 20-30 meters."
from: bss.sfsu.edu/ehines/geog646/646F02_class3.doc

By constructive interference I think they mean in phase amplification by wave strumming off of or refracted from an up current object, island in this case. An aerial photo of this appears below. Interesting stuff.

http://www.math.uio.no/~karstent/waves/neg1.gif

from: http://www.math.uio.no/~karstent/waves/index_en.html



More about this at:

http://www.esa.int/images/rogue-wave,1.jpg
http://www.esa.int/esaCP/SEMOKQL26WD_index_0.html

http://news.bbc.co.uk/1/hi/sci/tech/3917539.stm

http://www.sciencenews.org/pages/sn_arch/11_23_96/fob2.htm

[ricki]

Looking into this a bit more I came across ...

'h. Rogue waves are very rare large waves, probably due to unusual constructive wave interference. They are most frequent downwind from islands or shoals or where storm waves move against strong ocean currents, such as the Agulhas current off the southeastern coast of Africa. Rogue waves may sink or damage ships and often wash fishermen off rocks. Storm waves can often combine to produce waves as large as a 7-8 story building or 20-30 meters."
from: bss.sfsu.edu/ehines/geog646/646F02_class3.doc

By constructive interference I think they mean in phase amplification by wave strumming off of or refracted from an up current object, island in this case. An aerial photo of this appears below. Interesting stuff.

http://www.math.uio.no/~karstent/waves/neg1.gif

from: http://www.math.uio.no/~karstent/waves/index_en.html



More about this at:

http://www.esa.int/images/rogue-wave,1.jpg
http://www.esa.int/esaCP/SEMOKQL26WD_index_0.html

http://news.bbc.co.uk/1/hi/sci/tech/3917539.stm

http://www.sciencenews.org/pages/sn_arch/11_23_96/fob2.htm

[ricki]

Study: Ivan generated 91-foot-tall wave, suggests giant waves more common than thought

By RANDOLPH E. SCHMID
Associated Press
Posted August 4 2005, 3:13 PM EDT

WASHINGTON -- Last year's Hurricane Ivan generated an ocean wave that towered higher than 90 feet at one point, says a study that also suggests such giants may be more common than once thought.

Research indicates these are not ``rogue waves but actually fairly common during hurricanes,'' said David Wang of the Naval Research Laboratory at Stennis Space Center, Miss.


The giant wave was detected 75 miles south of Gulfport, Miss., by instruments on the ocean floor that measure the pressure of water above them. Using those readings, scientists can calculate the height of waves from trough to crest.

Last Sept. 15, as Hurricane Ivan passed through the area, the instruments measured 146 large waves, including 24 higher than 50 feet and one at 91 feet, Wang and his colleagues report in Friday's issue of the journal Science.

The giant wave did not reach land. Unlike a tsunami, which reaches down to the sea floor, this was a wind wave, generated on the ocean surface by the powerful forces of the storm.

Because shipping tends to try to avoid hurricanes, many large waves are unseen by humans, let alone measured. Scientists at the National Oceanic and Atmospheric Administration have a different way of calculating wave heights, using buoys at sea.

Hendrik Tolman, an ocean wave expert at the NOAA's Climate Prediction Center, said a wave such as the giant one measured during Ivan is within expected limits.

Ocean researchers generally focus on ``significant wave height,'' which is the average of the highest one-third of waves, he said. Within that average, there can be a much larger waves.

The highest significant wave height in Ivan was 52 feet as calculated by the NOAA buoys and 58 feet as calculated by Wang's group.

In a short-lived storm such as Ivan, a maximum wave of twice the significant height can occur, said Tolman, who was not part of Wang's research group.

Wang, however, said Ivan's towering wave exceeds those measured in other infamous storms.

``In 1969, Hurricane Camille produced a 44-foot wave by an oil rig near the storm's center,'' he said. ``Only two other buoy reports exceed the 52-foot mark set by Ivan, both of which occurred in the North Pacific where winter storms are larger than hurricanes,'' Wang said.

With forecasters expecting continued high hurricane activity in the next few years, this report should be a good starting point to increase wave-height research, Wang said.

On Tuesday, meteorologists at the National Weather Service increased their storm forecast for this year. There have already been eight named storms and they said there could be as many as 11 to 14 more tropical storms, including seven to nine more hurricanes, by the end of November.

Also, on Monday, Kerry Emmanuel of the Massachusetts Institute of Technology published a report indicating that global warming is making hurricanes stronger.

Wang's research was funded by the Office of Naval Research and the Interior Department's Minerals Management Service, which oversees offshore oil drilling.

On the Net:

Science: http://www.sciencemag.org

National Oceanic and Atmospheric Administration: http://www.noaa.gov

Naval Research Laboratory: http://www.nrlssc.navy.mil

[ricki]

Study: Ivan generated 91-foot-tall wave, suggests giant waves more common than thought

By RANDOLPH E. SCHMID
Associated Press
Posted August 4 2005, 3:13 PM EDT

WASHINGTON -- Last year's Hurricane Ivan generated an ocean wave that towered higher than 90 feet at one point, says a study that also suggests such giants may be more common than once thought.

Research indicates these are not ``rogue waves but actually fairly common during hurricanes,'' said David Wang of the Naval Research Laboratory at Stennis Space Center, Miss.


The giant wave was detected 75 miles south of Gulfport, Miss., by instruments on the ocean floor that measure the pressure of water above them. Using those readings, scientists can calculate the height of waves from trough to crest.

Last Sept. 15, as Hurricane Ivan passed through the area, the instruments measured 146 large waves, including 24 higher than 50 feet and one at 91 feet, Wang and his colleagues report in Friday's issue of the journal Science.

The giant wave did not reach land. Unlike a tsunami, which reaches down to the sea floor, this was a wind wave, generated on the ocean surface by the powerful forces of the storm.

Because shipping tends to try to avoid hurricanes, many large waves are unseen by humans, let alone measured. Scientists at the National Oceanic and Atmospheric Administration have a different way of calculating wave heights, using buoys at sea.

Hendrik Tolman, an ocean wave expert at the NOAA's Climate Prediction Center, said a wave such as the giant one measured during Ivan is within expected limits.

Ocean researchers generally focus on ``significant wave height,'' which is the average of the highest one-third of waves, he said. Within that average, there can be a much larger waves.

The highest significant wave height in Ivan was 52 feet as calculated by the NOAA buoys and 58 feet as calculated by Wang's group.

In a short-lived storm such as Ivan, a maximum wave of twice the significant height can occur, said Tolman, who was not part of Wang's research group.

Wang, however, said Ivan's towering wave exceeds those measured in other infamous storms.

``In 1969, Hurricane Camille produced a 44-foot wave by an oil rig near the storm's center,'' he said. ``Only two other buoy reports exceed the 52-foot mark set by Ivan, both of which occurred in the North Pacific where winter storms are larger than hurricanes,'' Wang said.

With forecasters expecting continued high hurricane activity in the next few years, this report should be a good starting point to increase wave-height research, Wang said.

On Tuesday, meteorologists at the National Weather Service increased their storm forecast for this year. There have already been eight named storms and they said there could be as many as 11 to 14 more tropical storms, including seven to nine more hurricanes, by the end of November.

Also, on Monday, Kerry Emmanuel of the Massachusetts Institute of Technology published a report indicating that global warming is making hurricanes stronger.

Wang's research was funded by the Office of Naval Research and the Interior Department's Minerals Management Service, which oversees offshore oil drilling.

On the Net:

Science: http://www.sciencemag.org

National Oceanic and Atmospheric Administration: http://www.noaa.gov

Naval Research Laboratory: http://www.nrlssc.navy.mil

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