Trittkarren

   (German.) These are best described as heel- print karren because they resemble the imprint of a heel. They are nearly connected with subhorizontal, adjacent, flat plains and migrate upslope by cutting ‘steps’ through the process of retrogressive corrosion. The semicircular form is preserved by the ‘horseshoe falls effect’ which concentrates the main amount of water on the innermost part of the heel-print. At the upper rim the water gain speed. The thickness of the film of water is indirectly proportional to the speed of the flow. A higher rate of flow results in a greater effectiveness of fresh precipitation added to the flow on the ground, but it also causes the diffusion of atmospheric CO₂ and more extensive corrosion. Most Trittkarren originate at the rim of a grike lying below and have moved upward to the surface through retrogressive corrosion. At the base of steep slopes where snow collects, nearly funnelshaped Trittkarren appear and are of subnival origin. They are common in the Alps [3].

   Synonym: heel-print karren.