Due to the steep topography of Heard Island , most of its glaciers are relatively thin ( averaging only about 55 m in depth ) .
80 % of the island is covered in ice , with glaciers descending from 2400 m to sea level .
Due to the steep topography of island   , most of island 's glaciers are relatively thin ( averaging only about 55 m in depth ) .
80 % of the island is covered in ice , with glaciers descending from 2400 m to sea level .