80 % of the island is covered in ice , with glaciers descending from 2400 m to sea level .
Heard Island is a heavily glacierized , subantarctic volcanic island located in the Southern Ocean , roughly 4000 km southwest of Australia .
80 % of the island is covered in ice , with glaciers descending from 2400 m to sea level .
Heard Island is a heavily glacierized , subantarctic volcanic island located in the Southern Ocean , roughly 4000 km southwest of Australia .