Just so you know there is no "reasonable limit" that an airline can stipulate to you. They are on the hook under the Montreal convention (to something like 1300+ per person max) if I get it right this time and if your purchases are essential, and the clothing is reasonable, then they must pay (they = the last operating carrier, as others mentioned). It may take a while and back and forth, but they have to.

You are under no obligation to unreasonably change your travel plans because of their shortcomings.

So don't sweat a purchase of rain coat and sweaters and what not and enjoy the beauty of Norway instead.