Earth pyramids

On the Ritten there are a number of earth pyramids, the best known of which are those in the Katzenbach valley below Oberbozen and especially those in the Finsterbach valley between Lengmoos and Mittelberg. One also can find earth pyramids near Unterinn.
The raw material for the earth pyramids comes from moraine clays deposited by the main Eisack valley glacier, as well as local tributary glaciers, in the late ice age.
When dry, this moraine clay is as hard as stone; dampened it forms a porridge-like substance which begins to slip and flow downhill. In this way, over a period of time, the saturated earth slides down into the stream below and is washed away.
This constant and continuous slippage is temporarily halted only when this erosion encounters a forest where the underlying ground is so dry that it is rock hard, which hinders further rapid slippage. This is how those steep cliffs, up to 10 to 15 metres in height and a pre-condition for the formation of the earth pyramids, are made.
Wherever the moraine contains larger stones which keep the earth underneath dry and hard, earth pyramids are formed by literally being "washed", or more precisely eroded, out of these cliffs. The higher the cliff and the higher up a suitable stone is found, the taller and mightier the resulting pyramid becomes. Because so many factors interact in its creation, it is difficult to say how long it takes for an earth pyramid to form.
It is also difficult to ascertain how old a pyramid is, or how long it will last. The only certainty is that the pyramid will rapidly disappear as soon as the covering stone falls of. However, as one pyramid disappears, new ones are being created elsewhere on the cliff, a process that will continue as long as the great moraine provides the raw material.