The fjords are an extremely interesting topographical feature. While they don’t have a great effect on the general climate of Scandinavia, they are the main influence on the local climate of the valleys in which they are located. Vikings have surely used fjords as protection from rough weather as their sharp angles could easily provide almost immediate relief from rough seas and strong winds.
When winds blow in any direction than that which the fjord faces, the wind will be slowed significantly as it is bent in its flow to move into the fjord. The associated motion of the seas are also slowed and bent (refracted) which causes a significant decrease in their height. Wave heights over the open North Sea may be as high as 16 to 20 feet along the coastal waters, but within the fjord due to the waves being refracted their height is only 2 to 4 feet or less. This is extremely significant for the Viking as they utilized the seas for trading and their raiding.