A deep, cold ocean current flows down from the North Pole, around the Canadian province of Newfoundland and Labrador, to meet the warm Gulf Stream traveling north from the Gulf of Mexico. Called the Labrador Current, it passes by the Arctic’s premier iceberg nursery off the coast of west Greenland. There, icebergs calve in great numbers, breaking off glaciers to float freely in the ocean. They drift northward up the coast until they meet the Labrador, then ride south in huge masses toward Newfoundland. Nowhere else in the world does this much ice intersect major shipping routes. The region deserves its nickname: Iceberg Alley.

Icebergs, fog, severe storms, and ocean traffic make Iceberg Alley one of the world’s most dangerous shipping areas. Temperature differences between the Labrador Current and the Gulf Stream, up to 68°F (20° C), produce dense fog and unsteady seas.

The officers of Titanic were well aware of the risks. A 1909 pilot’s guide supplied to the ship stated, “One of the chief dangers in crossing the Atlantic lies in the probability of encountering masses of ice, in the form of both icebergs and extensive fields of solid compact sea ice. Ice is more likely to be encountered in this route between April and August, both months inclusive, than at other times.” In fact, 1912 saw the heaviest ice for any April in the then-young century, a record that stood until 1972.

Forming the Ice Patrol

In the wake of the Titanic disaster, the International Convention for the Safety of Life at Sea (SOLAS) created the International Ice Patrol (IIP) in 1913. SOLAS mandated a 24-hour radio watch, boat drills, and lifeboats for all passengers on ships navigating Iceberg Alley. The IIP’s mission remains to “monitor the extent of the iceberg danger near the Grand Banks of Newfoundland during the ice season, and broadcast the location of the southeastern, southern, and southwestern limits of all known ice to interested shipping.”

Ice patrollers survey 1.3 million square kilometers (half a million square miles) by air each day, feeding data into a computer model of the Limit of All Known Ice (LAKI). They then broadcast the LAKI report via radio and the Internet, recommending specific lanes for safe passage.

Ice continues to be a shipping hazard in Iceberg Alley and across the North Atlantic, with hundreds of collisions since 1912. But thanks in part to the IIP and improved radio communications, no single incident has resulted in more than a hundred casualties.

  • The average iceberg is 1,982 cubic meters (70,000 cubic feet)—about 840,000 ice cubes.
  • Seven-eighths of an icebergs mass is below the waterline.
  • Melting an average iceberg takes the specific heat of 9.1 million liters (2.4 million gallons) of gasoline.
  • It takes 1,724 metric tons (1,900 tons) of TNT to blow up an average iceberg.
  • The tallest known iceberg in the North Atlantic was 168 meters (550 feet) high, sighted off Greenland in 1967.
  • Ice islands from Antarctica can reach the size of the U.S. state of Rhode Island.
  • Icebergs float because they are freshwater, which is less dense than saltwater.
  • Meltwater flowing off icebergs sustains whole colonies of krill (tiny shrimp), making them a magnet for fish, whales, seals, and polar bears.
  • Icebergs are most dangerous to ships when they turn over in the water. Don't go near them in a small boat!

region at Earth's extreme north, encompassed by the Arctic Circle.


person who has been injured or killed in a specific incident.


edge of land along the sea or other large body of water.


steady, predictable flow of fluid within a larger body of that fluid.

Plural Noun

(singular: datum) information collected during a scientific study.


clouds at ground level.


mass of ice that moves slowly over land.

Gulf Stream

warm current that starts in the Gulf of Mexico and travels along the eastern coast of the U.S. and Canada before crossing the North Atlantic Ocean.


large chunks of ice that break off from glaciers and float in the ocean.

Iceberg Alley

area in the North Atlantic Ocean with a large number of icebergs.

International Ice Patrol

organization that keeps track of the number, size, and movement of icebergs in order to warn ships.


to plan and direct the course of a journey.


fixed point that, along with the South Pole, forms the axis on which the Earth spins.


large body of salt water that covers most of the Earth.


division of a country larger than a town or county.

sea ice

frozen ocean water.

shipping route

path in a body of water used for trade.


severe weather indicating a disturbed state of the atmosphere resulting from uplifted air.


degree of hotness or coldness measured by a thermometer with a numerical scale.


luxury cruise ship that sank in the North Atlantic Ocean in 1912.