Here, a flute begins at the boulder and continues several 100 m into the distance, and many parallel flutes can be seen. Ice axe for scale. The present ice margin has been more or less stable in position since the mid-1980s. During the summer the ice margin melts back and sediment is released. Over a period of several years, a marginal moraine has accumulated.
Volcanic ash is derived from a thick bed that crops out at the upper limit of dirt-covered ice.
The 1918 tephra became buried within the accumulation zone and since has gradually migrated into the the ablation zones of several outlet glaciers. Note dark color of ice margin zone caused by heavy cover of reworked tephra and glacial sediment. The upper border of the dark zone marks the position of the 1918 tephra bed within the glacier. These gravels presumably were formed by englacial and subglacial outburst flooding during Katla's 1918 eruption. Active and abandoned melt-water tunnels are preserved at all levels along the ice margin at close intervals.