fiords

Fiord, also spelled fjord, is a long, narrow inlet with steep sides or cliffs formed by glacial activity. It is filled with seawater and connects to the ocean. The spellings fjord and fiord are used interchangeably; fiord is simply an alternative.

Geology and formation: Fjords are carved by glaciers into U-shaped valleys. As glaciers retreat, sea water floods the valley, creating a deep, narrow inlet. Many fjords have a shallow sill at their mouth, composed of glacial debris, which can limit water exchange with the open sea and reinforce stratified water layers. The walls are typically sheer and often host waterfalls.

Distribution and examples: Fjords occur in regions with recent or ongoing glaciation, including Norway, Iceland, Greenland, and parts of Canada, Scotland, New Zealand, Chile, and Argentina. Notable examples include Sognefjord and Nærøyfjord in Norway; Milford Sound and Doubtful Sound in New Zealand; and numerous fjords along the Chilean Patagonian coast.

Human use and ecology: Fjords support diverse marine ecosystems, including salmon and other fish species, and provide shelter for marine mammals. They are important for tourism, offering scenic cruises and hiking access, though some are remote. Local communities often use fjords for fishing, transportation, and, in some regions, hydroelectric power from river inflows.