Thunder Glacier is a through glacier

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

, 4 nautical miles (7 km) long, which extends in an east-west direction across Wiencke Island

Wiencke Island

Wiencke Island is an island long and from wide, about in area, the southernmost of the major islands of the Palmer Archipelago, lying between Anvers Island to its north and the west coast of the Antarctic Peninsula....

 between Sierra DuFief

Sierra DuFief

Sierra DuFief is a mountain range 4 nautical miles long with numerous sharp peaks, the highest 1, 415 m, extending in a NE-SW direction in the south part of Wiencke Island, in the Palmer Archipelago. Discovered by the Belgian Antarctic Expedition, 1897–99, and named by Gerlache for Jean DuFief,...

 and the Wall Range

Wall Range

Wall Range is a mountain range, 3 nautical miles long in a NE-SW direction with steep wall-like cliffs and jagged peaks rising to 1,095 m, extending from Thunder Glacier to Channel Glacier in the center of Wiencke Island, in the Palmer Archipelago. First mapped by the Belgian Antarctic...

, in the Palmer Archipelago

Palmer Archipelago

Palmer Archipelago, also known as Antarctic Archipelago, Archipiélago Palmer, Antarktiske Arkipel or Palmer Inseln, is a group of islands off the northwestern coast of the Antarctic Peninsula....

. Probably known since the discovery of Wiencke Island by the Belgian Antarctic Expedition

Belgian Antarctic Expedition

The Belgian Antarctic Expedition of 1897 to 1899, named after its expedition vessel Belgica, was the first expedition to winter in the Antarctic region.- Preparation and Surveying :...

 in 1898. Charted in 1944 by the Falkland Islands Dependencies Survey (FIDS), and so named by them because a survey party was nearly overwhelmed there by an avalanche.