The Setting of Gambell

The closeup map of the setting of Gambell, below, shows a steady drop in water depth going offshore from the beach, reaching a little less than 70 fathoms ( ~ 200 feet) within 50 km of the beach. The floor of the continental shelf, as shown on the middle map, covers more than half of the Bering Sea.

Map of the west end of Saint Lawrence Island showing Gambell, which faces west. All elevations, depth curves and soundings are in feet. The blue shaded area at sea is where the depth is equal to or less than 60 feet (just a little less than 20 meters.) The black, dashed line to the northwest of the island is the International Date Line. From Defense Mapping Agency, 1961.

Map of the Bering Sea showing the location of the Aleutian Islands, the International Date Line, the continental shelf and Gambell. Adapted from USGS, 2007.

Cross section along the International Date Line from the Aleutian Island Chain up to Gambell, Saint Lawrence Island. About 1,000 kilometers of deep water is followed by approximately 600 kilometers of shallow water, in which shallow water equations would apply. Chart adapted from data of USGS, 2007.

The cross section of the Bering Sea bathymetry, running from the Aleutians up to Gambell, shows that there are two very distinct underwater regimes between the Aleutians and the northern Bering Sea: the Aleutian Abyssal Plain and the continental shelf.

High seas in the northern Bering Sea are developed in the south, and propagate northward. The longest fetch, or area of wave generation, is to the southwest, roughly along the International Date Line. The associated deep water fetch is as much as 1,000 km. This is followed by a comparatively shallow fetch of approximately 600 km over the continental shelf.

Areas of open water, or polynyas, are known to form along favored stretches of the Bering Sea coastline. On Saint Lawrence Island, these areas are on the north and south coasts of the island. The west coast, which includes Gambell, is not so affected very often, except in easterly gales ahead of a storm in the western Bering Sea. Such a storm would be just the one to generate high seas in the far southwest and send them up to Saint Lawrence Island.

Mathematical Analysis

Qualitative Analysis