Glossary & Image Library

Lead

Any fracture or passage-way through sea ice which is navigable by surface vessels.

A more general description of a lead is an area of open water or new ice between ice floes, although the term is generally applied to linear features. If the open area is very large it may be called a polynya.

A lead between the shore and the pack ice is called a coastal lead or shore lead, and a lead between the fast ice and the pack ice is called a flaw lead.

Deep within the pack, leads provide vital access to the ocean for seals and penguins, and breathing holes for whales.		Leads permit large transports of heat and mass between the ocean and atmosphere, visualised in this image by the water vapour rising from the open water (sea smoke)