Freak Waves

These are not strictly a weather event . A freak wave is where there is a (say) 1 in 1000 chance that a wave will be abnormally large in a given sea state. In a flat calm 24 degrees like today it is possible that somewhere a 3ft wave will form . That is a freak wave ...but nobody will notice.

In a winter sea state the freak wave will be monsterous . The sea state itself is bad enough but the freak wave is a freak relative to the sea state. It is a bleedin monster

This post is about some of these events that maye be of interest . My personal view is that we are overdue a big one ...as are we overdue a strong solar storm not unlike the Carrington Event ...and we possibly even overdue a tsunami .

Horizon did a program some years back on freak waves, summarised here.

The best example they gave ( of immediate concern) was the Draupner Wave , a 26.6m pussycat that passed under a platform in the North sea . The draupner wave is of most interest because it was captured on radar and because we therefore know the shape of freak waves .

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

But it is a pussycat !!!

Around the same time The Fastnet Lighthouse was smacked by a much larger wave .

The light on the Fastnet Lighthouse is 48.5m above sea level

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



and yet , as the Economist documented last December a freak wave hit it while it was manned

In stormy winter weather, the “big seas would come sailing up over the entire building like the field of horses in the Grand National,” as one former Fastnet keeper put it. Sometimes, there were almost disastrous consequences; Mr O’Driscoll remembers a storm in 1985 when a wave reached as high as the light and came crashing through the glass, overturning the vat of mercury and sending the poisonous liquid pouring down the stairs. He doubts the tower would have withstood another wallop as great as that, but it never came. Suddenly, there was a great calmness.

It wasn't that 1985 was in some way exceptional. My next example comes from a history of the island of Mingulay which is in the outer Hebrides . South of it lies Geirum Mór , Geirum Mór has a height of 51m . One day the locals went out after a storm to find that all the sheep had been washed off the island by a wave . That was in 1868 .

On Flannan Isles just off the NW coast of the Outer Hebrides there were two events in December 1900. The first was documented by the lighthouse keepers who lived there.

http://en.wikipedia.org/wiki/Flannan_Isles#Mystery_of_1900

On top of the cliff at over 60 metres (200 ft) above sea level turf had been ripped away over 10 metres (33 ft) from the cliff edge.

The next event killed the poor bastards shortly afterwards , a matter of days at most . It may or may nopt have been another biggie.

However the BIG DADDY of the lot happened in Mayo . It smashed into a lighthouse on Eagle Island and luckily for the lighthouse keepers there were two lighthouses on Eagle Island .

The wave smashed the light on top of the lighthouse and poured into the lighthouse and down the stairs ....turning the lower levels into a swimming pool .

Were it not for the lighthouse keepers from the other lighthouse drilling holes in the door to drain the water the keepers may have starved to death in there .

The Eagle Island West Lighthouse was 68m above sea level .

http://cil2.adnet.ie/index.php3?LighthouseID=34

On the 11th March 1861 at midday the light room of the East tower was struck by the sea smashing 23 panes, washing some of the lamps down the stairs, and damaging the reflectors with broken glass beyond repair. It must have been an incredible wave to have come up 133 feet of rock and then a further 87 feet of lighthouse tower to cause so much damage. In spite of the efforts of the Keepers to repair the damage it wasn't until the night of the 12th that the light was restored and then only with 12 lamps and reflectors. Another interesting aspect of this disaster was that so much water cascaded down the tower it was impossible for the Keepers to open the door of the tower. They had to drill holes in the door to let the water out.

It took a few more hits over the years, This 68m above sea level structure was eventually abandoned.

Don't even start me on the Giant Boulders 25m above sea level on the Aran Islands

http://www.guardian.co.uk/science/2004/aug/18/environment.research