Giant Hole Discovered Under Antarctic Glacier According to scientists, it is the result of over 14,000 tons of ice rapidly melting into the ocean. They add that the ice which created the enormous hole started melting just three years ago. The six-mile long cavity was found underneath the Thwaites Glacier, which is located in the western part of Antarctica and is said to be the size of Florida. It has also known as the "world's most dangerous glacier." This is because its sheer size would greatly affect ocean levels should it melt at a fast pace. Studies say if all the ice on the Thwaites Glacier should disappear, sea levels around the globe would rise over eight feet.