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. Extremely unusual sightings in Bermuda and Ireland have occurred well outside of this normal limit.
Icebergs are mostly white because the ice is full of tiny air bubbles.
The bubble surfaces reflect white light giving the iceberg an overall white appearance. Ice that is bubble free has a blue tint which is due to the same light phenomenon that tints the sky. The blueish streaks of clear, bubble free ice often seen in icebergs results from the refreezing of meltwater which fills crevasses formed in the glacier as it creeps over land. The ice is blue because of the natural light scattering characteristics of pure ice. Simply put, icebergs melt.