I was on a Navy destroyer that was then part of a three ship task unit that was caught in a major hurricane in the north Pacific southeast of Japan in April 1969. With us was carrier Coral Sea and destroyer Porterfield. At the height of the storm, the winds were exceeding 140mph. The wave height as I recall varied from about 45' to +70'. The seas were very confused with gigantic long swells mixed in with gigantic sea waves.
The ship I was on was 437' long and 45' at the beam. Our fully loaded displacement was about 4200 tons. This is just provided for perspective.
At the height of the typhoon, with a head sea the ship was lifting her foot completely out of the water to 60' aft of the bow, all the way to the sonar dome. When we crested a giant swell and dove into the valley, our screws came completely out of the water. We were rolling about 45 degs. with great frequency. Just hanging on was a great accomplishment.
When we tied up in Yokosuka a few days later, I inspected the damage up forward and it was incredible. Virtually everything was either bent or simply ripped off of the main deck and the superstructure. We had an irregular crack about 1/2" wide and 24" long up in front of the anchor windlass. This was caused by the beating of the heavy seas and the flexing of the hull.
Unless you ride one of these out...it is really beyond comprehension. When we were in the worst of it, all I kept thinking about was the December 1944 typhoon that sank so many of Halsey's ships and sent so many good men to a watery grave.
When a storm like this one hits land...very bad things happen. If this beast hits Nawlins...they are truly screwed.