Occidental Glacier is an outlet glacier draining west from the Southern Patagonia Icefield. In 2015 the glacier terminus rested on the western shore of a proglacial lake where it bends to the northwest. At Point B a glacier lake was dammed by the ice front. From 2015 to 2021 the northwestern margin of the terminus retreated along the northern shore of the lake. By 2021 the lake at Point B was no longer ice dammed and its water level had declined. The terminus tongue (A) continued to extend to the western shore providing a stable pinning point through 2025.

In 2026 the connection to the western shore has narrowed with the embayment at Point B extending north and east. The terminus tongue (A) on March 22, 2026 is just 850 m wide and actively narrowing, note fresh icebergs. This connection is not stable and will not endure, which will generate significant terminus retreat. This glacier follows neighbors to the north Tempanos and Bernardo Glacier in this process each retreat leading to lake expansion, but also drainage of ice dammed lakes.