From Wikipedia encyclopedia: Uff da is an exclamation of Norwegian origin that is relatively common in the Upper Midwestern states of the U.S. It roughly means "drats," "oops!", or "ouch". It has become a mark of Scandinavian roots, particularly for people from North Dakota and Minnesota.
I guess I say this all the time but just never noticed it before. Someone finally brought it to my attention and asked me where it came from. "Good grief, I don't know", I replied. So after some research, now I know! My family (both parent's) all come from northern Iowa, almost into Minnnesota. Lots of redheads and probably Norwegian roots. Must have heard "uff da" has a child growing up and it stuck.
Someone once observed that if Charlie Brown was Norwegian, he would say "uff da!" instead of "Good Grief!". UFF DA