Professor wrote:

I have a K2 snowboard which seems to be in a mild "U" shape - the middle
touches the ground but the area under my feet do not. I can spin in a
circle without having to move down the mountain at all.

Does this indicate a board which is too stiff for my weight (125lbs and
149cm board) or did it get warped from storing it over the Summertime? Is
there anything I can do to it or SHOULD it be that way?


Something's definitely wrong. It sounds like the board is too stiff and
has a reversed camber. A normal board should behave like this:
* when put flat on the ground with no weight on it, the tip and tail
should touch the ground but the middle should be raised, due to the camber
* when you stand on the board, your body weight should flatten the board
against the ground

Your board is wrong on both counts and sadly I doubt if it can be fixed :-(
Iain