Pack ice sighted
 - Sea Ice

At the beginning of the austral winter starting around March, the loose pack ice that has spent the summer months circling Antarctica begins to drift northwards. Pack ice is old sea-ice, frozen sea water that is a year old or more, it froze and formed elsewhere and later floated off with the winds and currents. Pack ice is heavy stuff and when it arrives somewhere it has the effect of steadying the ocean swell. The continuous rolling motion of the sea is stopped completely by a relatively narrow band of pack ice only 100m or so wide. The result is that where pack ice is present in reasonable quantity, the sea calms down sufficiently for low temperatures to freeze it easily - moving water cannot freeze as easily as static water.