16 Blades, as a hurricane is essentially made up of a huge spinning mass of CB cloud, in the case of Katarina with tops to FL520 (yep, 51000 FT deep CBs), then you can imagine that flying through one would be very unlike flying through a jetstream which is more often than not constant (though rapid) flow of air; only in some cases do jetstreams produce CAT. Nor would it be anything like the CBs we get in the UK (or even over Europe) where tops rarely get above FL400. The comparison is just slightly off.