In article om,
Weatherlawyer wrote:
There were two "once in a hundred years" storms in the North Sea in the
1980s... within three months of each other in 1987.

For future reference Spencer has seen the error of his ways and
realised that certain regions of the UK have ""once in a hundred years"
storms" quite often.

Uh, no, sorry, wrong. The definition of a "once in a hundred years" storm
for a region is based on local storm history. It's the level of storm
which, *on average*, would be expected to occur there once a century. The
point I was making is that averages are not to be trusted too much,
because coincidences happen.

The "once in a hundred years" level of storm is significant because it's
a common engineering design criterion for things like North Sea oil
platforms. How much weather do you design the platform to withstand?
There's no particular upper limit on what Mother Nature can throw at you
if she's feeling mean, but the higher you set the bar, the more money
you're spending on precautions against quite rare events. One common
criterion is to design to safely withstand a "once in a hundred years"
storm, and take your chances with still more violent (and hence likely
to be still less frequent) storms.
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