Katrina downgraded to Cat 4

[Cornishman]

It has just been announced that Hurricane Katrina has been downgraded from Cat 5 to Cat 4 (160mph to 155mph winds!) which I guess is merely academic.
Does anybody here know if there is an extended Beaufort wind force for this, and if so what is it?

 

[kindredspirit]

Hurricane scales (Saffir-Simpson) here.

http://www.nhc.noaa.gov/aboutsshs.shtml

New Orleans is on average 6 feet below sea level and the levees are 14 feet high so if they get a storm surge you know what happens.

See link in Lounge for very detailed picture.
.

 

[Lakesailor]

CNN have live pictures

 

[peterb]

Beaufort scale has been extended recently, but I'm not sure how far.

If you like to check, wind speeds up to F12 seem to follow a three halves power law. The mid-range speed is about 1.63 times the Beaufort number raised to the power 1.5. Although that's only from personal observation, the fit is so close that I'm sure it's not accidental, and that that's the way the scale was constructed. On that basis, 160 knots would be about Beaufort F20. Gentle breeze, anyone?