Dunno what counts as "Northern Europe", but in Poland nobody uses powered dryers, it's all natural. And it gets to -20 C in the winter here sometimes. Dry cold is not actually a problem for drying clothes.
I'm Polish and we've always had a dryer at home, no idea how my mum would have gone through that pile of loundry she always did otherwise. So YMMV.
And the problem in the UK is that relative humidy is so high you literally start getting mold inside your house if you just use an airing dryer, as most people do, a lot of houses have that characteristic "musky" smell because they are just too damp. In poland the air is a lot dryer(especially in winter!) so you don't get this problem.
I think that there are two assumptions that we tend to make that causes the idea of air drying frozen clothes to be unintuitive:
1. We don't expect solids to evaporate, because it's not something we notice often (though if you think about the fact that a few inches of snow can disappear in a couple of days while the temperature remains below zero Celsius, you suddenly realize that you do observe it if you live in a cold climate)
2. We're so accustomed to using heat to speed the evaporation of water. So we might assume that removing large amounts of heat energy will "stop" evaporation. Or at least cause it to slow so much that air drying becomes impractical.
But ice does, indeed evaporate (to be accurate, it sublimates). My question is how temperature affects the speed of evaporation at low temperatures. How long do you need to leave your wet clothes hanging below freezing before they are dry?
I live in a place where there is ice outside all winter. During winter the cold air can't hold moisture as much as hot air and most of the days are at 100% humidity even at -20 because the air simply can't hold more.
I might try this out on the deck next season but I don't assume ice is just going to sublimate away because it's literally outside all winter and doesn't go anywhere.
They evaporate faster in the cold, because the air is very dry when it's very cold. Or sublimate I guess? In any case they usually don't freeze unless they are very wet (which rarely happens - people use washing machines that rotate very fast for the last few minutes of washing to remove most of the water mechanically).
And when they do freeze it's not like cloth encased in ice, it's more like the clothes still look and feel dry - they just hold their shape :) If you put them at room temperature they finish drying within minutes.