A majority of the icebergs in the North Atlantic come from about 100 iceberg producing glaciers along the Greenland coast while a few originate in the Eastern Canadian Arctic Islands. The icebergs we see off Newfoundland are carried south in the cold Labrador current. The numbers vary greatly from year to year and seasonally as most are seen off Newfoundland in the spring and early summer. The icebergs that reach the east coast of Newfoundland probably calved from a glacier more than a year before. Rarely do icebergs last more than one year south of this point.
Glaciers form on land as a result of a net accumulation of snow over thousands of years.
Successive layers compress earlier accumulations until, at depths below 60 to 70 meters, glacial ice is formed. When the edge of a glacier advances into the ocean the pieces that break off are what we call icebergs. Iceberg drift speed is actually influenced by many factors including iceberg size and shape, currents, waves and wind. Icebergs often take quite eccentric paths so that the distance travelled by a berg may be two or three times the straight line distance over a week or so. Before some icebergs completely deteriorate they may travel many thousands of kilometers.