Explosive Cyclogenesis ... ... and the joys of really big storms.

Alex Dick-Read

By Tony Butt

[This article first appeared in The Surfer's Path in 1999. We thought, with a 928mb low about to turn the North Atlantic into a maelstrom of memorable proportions, this aint a bad time to brush up on our explosive cyclogenesis, and some of the biggest storms in North Atlantic history]

MetOffice

Met Office chart for January 26th, 2013
 
 

The weather forecast is showing a huge low just west of Ireland. Its about to deepen even further, and swing east over the UK. Its
 isobars are so close they’re almost touching. The centre looks like
a solid black mass. The weather manis warning of impending doom.
 Lives will be endangered, there’ll be heavy financial repercussions,
 insurance claims and a strong chance that many people’s worlds will 
fall disastrously apart.
 Meanwhile, you’re stoked. The storm is out there, and the swell is 
inevitable. It’s like you just won the lottery and all you have to 
do is wait for the money to come in. You start planning with glee -
what board, which spots, which days and times will be best….
To many surfers this is a big part of surfing. If you’ve been doing 
it for a number of years, the biggest, meanest storms that appear on 
the weather chart will end up sticking in your memory. Some of them
 may never have produced rideable surf for you, but nonetheless, 
they’re a source of fascination.
 This article is about some of the deepest lows that have existed in
the North Atlantic, and some of the most disastrous storms that have
 ravaged the UK, from where I write. These storms are well documented 
in the meteorological literature, and they have often been given
 names (like hurricanes), just to add to that air of human-like
 unpredictability.

The Fastnet Storm, August 13th 1979

A flotilla of yachts set sail from Cowes, Isle of
 Wight. They were supposed to race to Fastnet Rock, and then back to
 Plymouth. Of the 303 that set out, only 85 made it. Fifteen lives
 were lost and 136 people had to be rescued by helicopter. This
 well-known disaster, the Fastnet Storm, was caused by winds of over
80mph, whipped up by an unexpected low pressure system which
 developed over Ireland. It wasn’t actually that deep, (about 980mb),
but the fact that all those boats got caught out, makes it a real 
tragedy.
 One interesting thing about the Fastnet Storm is that with all those 
boats stuck right in the middle of a large mid-latitude depression,
 each one carrying a barometer and an anemometer, a very
 comprehensive study of what goes on inside one of these lows was
 able to be made. Also, the reports of some of the surviving crews
 were valuable to meteorologists, like descriptions from the crew of ‘The Gremalkin’, talking of waves “like blocks of flats…”

 

grim

The stricken boat Gremalkin after a night of 30-60ft seas in the Fastnet Race, January, 1979

 

The Great Storm of 15-16 October 1987

This was 
the one where Michael Fish, the weatherman got ripped to shreds by
the media for not predicting it the day before. The Sun newspaper 
even called for the resignation of Professor J. T. Houghton,
 Director-General of the Met. Office. Personally I don’t know what
 the fuss was about. I clearly remember the weatherman saying “…it
 will be very breezy in the Channel…”
This storm didn’t produce much in the way of surf because it
 deepened to about 956mb when it was already over the land. However,
 it did cause considerable damage to the heavily populated south of 
England. With gusts of over 115mph, eighteen people lost their 
lives, and an estimated 25 million people (and 15 million trees)
were affected in one way or another.
 There is an endless list of incidents connected with this storm. For 
example, at Porthleven, three people had to be rescued when their 
own rescue helicopter ditched into the sea, and at Harwich a prison 
ship containing 50 inmates broke free from its moorings and drifted 
around for two hours. And minutes before a tree smashed down his 
house, Dr. H. Lawes of Noble Denton Weather Services reports, “…I
 telephoned the forecast office… the synoptic situation sounded
 interesting from an academic point of view, but following another
 loud crash I put the telephone down rather hurriedly”.
Again, the Burns Day Storm of 25 January, 1990 got to its deepest 
after it had settled over Northern England, but it did generate 
enormous swell earlier on, as it deepened just west of Ireland. Most 
recognised breaks north of Southern Portugal were out of control,
 although spots south of there were going off. On the land, it was a
 similar story to the Great Storm of ‘87. Millions of trees got blown
 down, 47 people lost their lives, and hundreds of millions of pounds 
worth of damage was caused.

 

braer_chart

Brear Storm 1993 was predicted to drop to 909mb but in the end it only reach 914mb. Only.

The Lowest Lows

Sometimes, all the factors to do with the jet stream, the sea
surface temperature, the polar ice, the butterfly flapping its wings
10000 miles away etc., all coincide to produce a depression which 
gets incredibly low. Usually these lows suddenly deepen, as if they
 were always ready to be triggered off. In the world of meteorology, 
if a low deepens more than 24mb in 24 hours it’s called “explosive 
cyclogenesis”.
The two lowest barometric readings recorded in this part of the 
Atlantic have occurred in the eighties and nineties. The first was
 the Atlantic Cyclone of 15 December 1986, which got down to 916mb,
and the other one was the Braer Storm of 10 January 1993. The Braer Storm has been much better documented. It took its name from the
 final destruction of the Braer, a large, loaded oil tanker which had 
become stranded on rocks off the Shetland Islands by another storm a
 week earlier. Dipping to 914mb, it has been acknowledged to be the 
deepest Atlantic mid-latitude depression ever recorded. The experts 
thought it was going to deepen even more. I can remember vividly
 listening to the Shipping Forecast from a crackling old radio whilst 
huddled in the back of a van at Mundaka: “Rapidly deepening Atlantic 
low, expected just west of Bailey, 909mb”, and the wind for Bailey
 was “… Force twelve or more…” which is also quite rare. Needless 
to say we were expecting some surf.

What Sort of Surf do These Storms Bring?

Not necessarily that good. It depends on so many other factors, like 
the fetch length, how long the storm stayed in one place, the
 direction of the fetch, etc. The Braer Storm produced some great
 surf, but not really as big as many had expected. The low didn’t
 persist long enough, despite a very tight, intense centre similar to
(but not the same as) a hurricane.
 On the other hand, the Cyclone of ‘86 probably produced some
 all-time surf throughout the whole Atlantic. I was in Morocco at the 
time, and I remember some local rolling up with a newspaper on a
 rickety old bike; “Hey meester, beeg waves for joo, no feeshing for
us”. Even he could see there was something unusual about today’s 
weather chart. It took six days for that swell to arrive, but when 
it did, it was 10ft and super-clean.
 Anyway, the general consensus is, these storms definitely produce 
big waves, and the more of them there are, the more often we’ll get
 big surf in the Atlantic.

 

Screen Shot 2013-01-25 at 7.08.03 PM

Hmm … Morocco. Not a bad place to be in the next few days. Photo: Ricardo Borghi

 

So Is the North Atlantic Getting Stormier?

Well, yes, so it seems. And not only that, but the thing that 
affects us directly, namely wave heights, have been shown to
 increase significantly over the last few decades. Measurements from
 wave buoys and weather ships have shown that, in 1960, the maximum 
wave height in the Atlantic was about 12m. There has been a
 systematic increase, and now, in the late nineties, the average
 maximum height is around 18m. Long-term trends in wave heights are
 intimately linked with how stormy the ocean is, so we can safely say 
that the Atlantic has got quite a bit stormier since the early 
’60s. Whether this trend will continue is anybody’s guess. It’s 
probably just the upward side of a much longer-term oscillatory
 pattern (like El Nino, but over many decades). We haven’t got good 
enough meteorological records for that – we don’t really know.
For people like myself, who strive to try and
 predict these types of things, it’s tough, even as our forecast models get better and better. On one hand we have 
to fool ourselves, and those who pay us, that one day we might be able to
 predict everything (otherwise we’d give up altogether). On the other
 hand, we must keep in mind that forecasting is inexact. The fundamental laws of quantum mechanics forbid us from 
making perfect predictions of anything, let alone the weather.
Which 
is a really good thing, because otherwise both surfing and science
 would be forever predictable, and not worth a whistle in the wind.
Tony Butt is author of The Surfer’s Guide to Waves, Coasts and Climates, published by Alison Hodge. If you want a copy, you can get one free right now by joining Surfers Against Sewage, here.

This article first appeared in The Surfer’s Path way back in 1999.

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