Press hill
Press ice hills , also press ice backs , English hummock , are the elevations in the pack ice that are piled up by lateral pressure at the contact point between two or more ice floes . They can be fresh or already weathered. The volume of ice pushed down is called a bummock .
The press ice mounds arise when ocean currents and winds exert pressure on the pack ice. The hills have an average above-ground height of one to two meters, below sea level they can protrude up to 20 meters. The press ice hills give the pack ice its characteristic appearance: wide, flat ice surfaces, criss-crossed by numerous long miniature mountains.
The press hills are one of the reasons for the difficult locomotion in the Arctic and Antarctic and represent a significant obstacle for icebreakers .
Hummock-like shapes can also arise from debris flows, e.g. B. in the deposition area of volcanic debris avalanches .
