Are glaciers dangerous?

Glaciers usually are found in remote mountainous areas. However, some are found near cities or towns and sometimes present a problem for people living close by. On land, lakes formed on top of a glacier during the melt season may cause floods. At the snout (or terminus) of a valley glacier, ice falling from the glacier presents a hazard to hikers below. When ice breaks off over the ocean, an iceberg is formed. Some examples of these hazards are listed below.

Flooding Caused by a Glacier

In Peru in 1941, 6,000 people perished when a glacial lake suddenly burst open, flooding the town of Huaraz below it. Since then, another lake has formed at the base of the glacier, but engineers have created artificial channels to prevent future flooding.

Avalanches from Glaciers

Ice avalanches from glacier snouts have been recorded in the Swiss Alps for centuries, and they still happen despite attempts to prevent them. In 1965, Switzerland was constructing a dam for a hydro-electric plant above the town of Mattmark. Without warning, an enormous mass of ice from the tongue of the nearby Allalingletscher broke off. In mere seconds, the avalanche had rushed down the slopes and buried much of the construction camp, killing 88 workers.

The Threat of Icebergs

Icebergs broken off, or calved, from ice shelves and tidewater glaciers pose a significant threat to sea lanes worldwide. One of the most famous examples is the Titanic, which in April 1912 carried 1,503 passengers to a watery grave after a collision with an iceberg that ripped a 90 meter hole in the ship. Shipping lanes along the coasts of Greenland and Newfoundland are historically iceberg-infested waters.

Icebergs calved by glacial ice continue to present problems even today. Recently, an enormous iceberg, over 80 kilometers long and 40 kilometers wide, broke away from the Larsen Ice Shelf in Antarctica. Because this iceberg may threaten southern shipping routes, it is being carefully observed by satellites and aerial survey.