Weather Banter - View Single Post - Super-typhoon Maysak

Metman2012 · April 1st 15, 04:20 PM posted to uk.sci.weather

On 01/04/2015 14:11, Martin Brown wrote:
On 01/04/2015 13:51, wrote:
Graham

Do you know if the Japanese use a 1 minute mean when they issue
tropical cyclone warnings?

As an observer here in the UK, you often got a very short peak in wind
speed on a frontal passage
or some kind of trough or squall line, but it would very rarely last
a full 10 minutes.

According to Wikipedia "the value of a one-minute sustained wind is
14% greater than a ten-minute sustained wind".

To me a 1 minute mean is almost akin to a gust but I'm just a
miserable old sod.

It would be interesting to know what does all the damage in a storm -
the extreme gusts or the sustained mean speed -
my money would be on the mean doing as much damage as the gust.

My instinct would be that the repeated flexing of structures caused by
the strongest gusts would be far more structurally damaging than the
sustained deflection caused by a steady wind loading at mean speed.

I would hazard a guess that damage scales with both windspeed and the
variance of windspeed. Specific impulse delivered to a fixed obstruction
per unit time scales with windspeed squared so I reckon that the gusts
will almost always be the main destructive force.

Once the wind gets inside a structure all bets are off.

I think you're right; when claiming for wind damage to your house you
need to be able to quote gusts higher than about 38 mph (IIRC). Rain
doesn't damage houses, although it can exacerbate damage already caused
by other factors.

This was a while ago, perhaps it's all changed....