Along the northern coast of Alaska, bordering the Chukchi and Beaufort Seas, river deltas and barriers characterize the coastal landscape. There are barrier islands and cuspate forelands that resemble similar features on the Atlantic coast. Sediment in this region is derived from rivers draining the Brooks Range and the Canadian Rockies. These rivers build deltas into the sea, thereby providing substrate for barrier formation by the waves and currents. Even though the rivers and ocean are frozen for much of the year, there are significant amounts of sediment present to encourage delta and barrier formation.
Beaches are not static during the frozen months, however, as sea ice is pushed along the shore by wind, a process which moves sediment along the shore and offshore.