Fjord

A fjord is a long, narrow sea inlet bordered by steep cliffs, formed primarily by glacial erosion and subsequently filled by seawater. The term fjord derives from the Norwegian fjord, from Old Norse fjǫrðr, meaning an arm of the sea or a firth.

Formation occurs as glaciers carve U-shaped valleys during repeated advances and retreats of ice. When the glaciers melt, sea water flows into the valley, creating a coastal inlet. Many fjords exhibit a shallow threshold or sill at their mouth, left by glacial debris, which can influence water exchange and circulation. Fjords are typically deeper inland than the adjacent sea, and their interiors often contain spectacular vertical relief and waterfalls.

Fjords are characteristic of high-latitude coastlines around the world, including Norway, Iceland, Greenland, Canada, Chile, and New Zealand. Notable examples include the Sognefjord and Geirangerfjord in Norway, Milford Sound in New Zealand, and the Saguenay Fjord in Canada. Some fjords extend many tens of kilometers inland and host rugged, cliff-lined scenery that contributes to their iconic status.

Ecology and human use vary along a fjord’s length. The steep sides create specialized habitats, and the salinity can shift from seawater to brackish or freshwater in upper reaches. Fjords are important for tourism, shipping, and sometimes hydroelectric power generation, as well as traditional fisheries in coastal communities.