A type of sea ice defined by the WMO as: Term used in a wide sense to include any area of sea ice, other than fast ice, no matter what form it takes or how it is disposed. Pack ice is described as very open (ice concentration of 0.1 to 0.3), open (0.4 to 0.6 with many leads and polynyas, with the floes generally not in contact), close (0.7 to 0.8, composed of floes mostly in contact), very close (0.9 to less than 1.0), and compact (1.0, with no water visible, and called consolidated pack ice if the floes are frozen together).