Well, if we have winter and frozen lakes, this means adventuring for snow or ice isn't so important, so how about this:
The ability to mine/chip ice lakes for solid ice, which could be used to make curios and even some other items (Ice cubes that function like spices, except for drinks?). Ice should melt like snow does.
A large storage building that can store ice and snow (with a limited inventory, of course) indefinitely during winter, spring and fall; but the ice slowly melts down over the duration of summer (or just indefinitely?)