Landsat 7 spacecraft took this picture on February 21, 2000. The Larsen Ice Shelf is one of several so-called ice shelves in Antarctica. Although not the largest, experts consider it to be most in jeopardy of further recession due to its comparatively northern position. In this sequence, we see how the ice there has changed through time, starting in December 1993 and ending in March 2000. The mechanism that rends vast stretches of Antarctic ice from its moorings is similar to what causes roads to crack in late winter.
Cracks form in the ice shelf for a number of reasons.
But crevasses often appear along the landward side of the shelf as ice moving in glaciers grinds past features on the coast and plows into the ice on the shelf. As melting water on the surface of the shelf fills in those fissures and crevasses, pressure builds in the structure of the sheet. That process can either increase gradually, or it can be repeated seasonally. What happens is a gradual splintering of a wide section of shelf, which is then ultimately rent asunder by tides or storms. The process is believed to be more a function of mean summertime temperatures, as opposed to overall annual temperatures.