Re: [Phys-L] measuring hurricane strength

[John Denker <jsd@av8n.com>]

On 09/01/2017 03:32 AM, Folkerts, Timothy J wrote:

> NOAA's "ACE" is the closest thing I know to a measure of both
> strength and persistence for hurricanes, and it doesn't show any
> particular upward trend over the decades.

There has never been a "category 6" hurricane, because the Saffir-Simpson
scale only goes up to 5.  There is no defined upper bound to category 5,
and no category 6, because the guys who proposed the scale could not
imagine a storm strong enough to require one.

HOWEVER ... if we were to define a sixth category in a way that is
consistent with the pre-existing categories, Irma would be up in
the middle of category 6.
   https://www.av8n.com/physics/img48/hurricane-scale.png

Irma is the strongest storm ever observed in the open waters of
the Atlantic ocean.

One could also argue that the S-S scale ought to be replaced
or at least supplemented by other criteria.  It only measures
strength at the core, whereas for some purposes we care about
things that are not necessarily well correlated with that,
e.g. spatial extent.

Irma is big as well as strong.

On 09/04/2017 09:22 AM, LaMontagne, Bob wrote:

> Have we forgotten the Galveston hurricane of 1900?

That was category 4.  It was particularly deadly due to a lack
of long-range planning.  There was also a lack of short-range
planning, in part because there was no reliable forecast until
less than 24 hours before the storm surge arrived.

Satellites and aircraft save lives by the thousands when
something like this happens.  Think about the the next time
some demagogue says he wants to abolish the Department of
Commerce.