floating ice mass drift ice mass 2019-01-14T19:46:20Z http://sweetontology.net/realmCryo/DriftIce drift ice Prior to approximately 2014, drift ice was synonymous with the various grades of pack ice, described as very open (with an ice concentration of 1/10 to 3/10), open (4/10 to 6/10, with many leads and polynyas and the floes generally not in contact with one another), close (7/10 to 8/10, composed of floes mostly in contact), very close (9/10 to less than 10/10), and compact (10/10, with no water visible, called consolidated pack ice if the floes are frozen together). This is deprecated, with pack ice now referring to drift ice with a concentration equal to or above 7/10; however, other usages are still common. A floating mass of ice which is 1) unattached to land or land-fast ice and 2) moved by the action of winds or currents.