Fast ice in the context of "Drift ice"

A pressure ridge is a linear pile-up of sea ice fragments formed in pack ice by accumulation in the convergence between floes in an oceanic or coastal environment.

Such a pressure ridge develops in an ice cover as a result of a stress regime established within the plane of the ice. Within sea ice expanses, pressure ridges originate from the interaction between floes, as they collide with each other. Currents and winds are the main driving forces, but the latter is particularly effective when they have a predominant direction. Pressure ridges are made up of angular ice blocks of various sizes that pile up on the floes. The part of the ridge that is above the water surface is known as the sail; that below it as the keel. Pressure ridges are the thickest sea ice features and account for up to 30–40% of the total sea ice area and about one-half of the total sea ice volume. Stamukhi are pressure ridges that are grounded and that result from the interaction between fast ice and the drifting pack ice. Similar to undeformed ice, pressure ridges can be first-, second-, and multiyear depending on how many melt seasons they managed to survive. Ridges can be formed from ice of different ages, but mostly consist of 20–40 cm thick blocks of thin and young ice.

Antarctic sea ice is the sea ice of the Southern Ocean. It extends from the far north in the winter and retreats to almost the coastline every summer. Sea ice is frozen seawater that is usually less than a few meters thick. This is the opposite of ice shelves, which are formed by glaciers; they float in the sea, and are up to a kilometre thick. There are two subdivisions of sea ice: fast ice, which are attached to land; and ice floes, which are not.

Sea ice that comes from the Southern Ocean melts from the bottom instead of the surface like Arctic ice because it is covered in snow on top. As a result, melt ponds are rarely observed. On average, Antarctic sea ice is younger, thinner, warmer, saltier, and more mobile than Arctic sea ice. Another difference between the two ice packs is that while there is clear Arctic sea ice decline, the trend in Antarctica is roughly flat. Antarctic sea ice is not studied very well in comparison to Arctic ice since it is less accessible.

Foxe Basin is a shallow oceanic basin north of Hudson Bay, in Nunavut, Canada, located between Baffin Island and the Melville Peninsula. For most of the year, it is blocked by sea ice (fast ice) and drift ice made up of multiple ice floes.

The nutrient-rich cold waters found in the basin are especially favourable to phytoplankton and the numerous islands within it are important bird habitats, including Sabine's gulls and many types of shorebirds. Bowhead whales migrate to the northern part of the basin each summer.

A stamukha (plural: stamukhi; from Russian стамуха) is a grounded accumulation of sea ice rubble that typically develops along the boundary between fast ice and the drifting pack ice, or becomes incorporated into the fast ice.- see also NSIDC. It is a pressure ridge. Wind, currents and tides contribute to this phenomenon. Stamukhi tend to occur in belts that are parallel to the shoreline, along coastal shoals, at water depths of about 20 m (65 ft), but that can reach 50 m (160 ft). They can build up to heights 10 metres (33 ft) or more above the waterline. Although they remain pinned to the seabed, these features can be subject to small displacements, either due to thermal expansion or to the pressure exerted by the drifting pack ice onto the fast ice. Because stamukhi tend to be deeply grounded, they may occur as isolated ice features in the open sea during the summer season, after the surrounding ice has melted away.

Since stamukhi extend downward into the seabed, they present a risk to submarine pipelines and telecommunications cables that cross the shoreline. Seabed penetration by the ice can reach a depth of 5 metres (16 ft).