How are the fjords formed? Why do they constitute some of the most picturesque areas of the world?

Fjords are long, narrow, deep arms of the sea flanked by steep cliffs, formed where glaciated valleys have been drowned by the sea. They line high-latitude coasts of Norway, Greenland, Alaska, British Columbia, Patagonian Chile and New Zealand.

How fjords are formed

• During glacial periods, valley glaciers occupied pre-existing river valleys running to the coast.
• Intense glacial erosion by plucking and abrasion deepened and widened these valleys into U-shaped troughs, often excavated far below sea level — Sognefjord in Norway exceeds 1,300 m in depth.
• As the glaciers retreated and post-glacial sea levels rose, the sea invaded the overdeepened troughs, creating fjords.
• A shallow threshold or sill of rock and moraine at the mouth marks the zone of reduced erosion near the glacier's snout.

Why they are so picturesque

• Dramatic contrast of near-vertical rock walls rising from calm, deep blue water against snow-capped peaks.
• Hanging valleys discharge spectacular waterfalls, such as the Seven Sisters of Geirangerfjord.
• Sheltered, winding waterways with islands, mist and glacier snouts create scenery of rare grandeur.
• Rich marine and bird life adds ecological charm to the landscape.

The West Norwegian Fjords (Geirangerfjord–Nærøyfjord) are UNESCO World Heritage sites and, with Milford Sound, sustain major cruise and adventure tourism economies.