Glacial Cirques

Cirques (serks) are formed by snow and ice building up on the side of the mountain (at the headwall).By plucking and through abrasive action, the snow and ice (which, under pressure and continued freezing becomes known as firn) forms a semi-circular amphitheater in the rock base. After the period of cold climate and when the ice is gone, the cirque is exposed and may fill with water forming a tarn lake. Successive stair steps of tarn lakes can occur in a chain of lakes going down a glacial valley. This is the result of the continual advance and retreat of glacial ice up and down the alpine glacial valley. Glacial lake chains are known as paternoster lakes...because they resemble a chain of beads...such as those on the paternoster or rosary.

The above image shows a small cirque and glacial lake system in the Cascades, just west of Mt. Rainier. This picture was taken during the spring of the year so the lakes are still frozen and covered with snow. At one time this cirque was completely covered with ice. Alpine lakes like such as these offer incredible recreational opportunities for hiking, camping, and fishing.

---