National Geographic : 1926 Jul
STANDING ICEBERG GUARD IN THE NORTH ATLANTIC Photograph from Lieut. Commander F. A. Zeusler READY TO STAND WATCH ALONG THE LANES OF TRAVEL IN THE NORTH ATLANTIC The Modoc and the Tampa comprise an international fleet, for while these Coast Guard ships fly the United States flag and are manned by American officers and seamen, the patrol is maintained in the names of Belgium, Canada, Denmark, France, Germany, Great Britain, Italy, Netherlands, Norway, Sweden, and the United States (see text, page 4). the source of the icebergs that come as far south as the steamer lanes, journeying about i,800 miles-approximately the dis tance from Washington, D. C., to Den ver-before they become "white specters" to shipping. With the exception of a small strip of coast line, Greenland is completely cov ered with a vast ice cap.* Its estimated thickness is 5,000 feet. Always the ice mantle is moving down the slope of the land toward the sea, in great glaciers, pushing out through the valleys. As the ice reaches the sea it noses out into the water until buoyancy lifts it up, and then the front of the glacier breaks off at a weak spot. There is a deafening roar and a thun derous crash, and with a tidal splash the glacial fragment plunges heavily into the sea, almost submerging. The water is * See "Flying Over the Arctic," by Lieutenant Commander Richard E. Byrd, in the NATIONAL GEOGRAPHIC MAGAZINE for November, 1925.