Why do homes in Sweden and Norway have steep roofs?

Sweden and Norway, both of these countries have a very severe cold climate and snowfall is a usual for them.

In areas of heavy snowfall, like Sweden and Norway, flat roofs would be loaded with a lot of snow which may cause some loss to the roofs and may lead it to crack.

So these steep roofs do not allow any water or snow to accumulate on the top of the roof and makes it easier for the snow to slide off it.