South Lake is reached by a moderate to strenuous hike into the Dinkey Lakes Wilderness. It is approximately 3 miles from the parking area and at an elevation of about 9300 feet. The parking area is accessible by unpaved Forest Service access roads. The roads do get pretty rough, so a high clearance vehicle would be a very good idea. Winter snows make the Waymark inaccessible.
The Sierra Nevada Mountains have been repeatedly covered with glaciers over the past 1.5 million years. Due to the erosive nature of glaciers, each successive glaciation typically erases the evidence of prior glaciations. As a result the timing and number of glaciation events is constantly under debate.
However, some glaciations have been either extensive or lasted long enough to have left evidence of their occurrence. The Sherwin Glaciation, which occurred about 1 million years ago, is one of these major glaciations. The two most recent events are called the Tahoe and Tioga glaciations. The Tahoe glaciation is thought to have occurred in two stages between 200 and 140 thousand years ago and from 50 to 42 thousand years ago. The Tioga glaciation is more recent, occurring between 25 and 14 thousand years ago. Of the two recent glaciation events, the Tioga glaciation is thought to be just a little less extensive than the Tahoe.
Glaciers leave distinctive geomorphologic features. These features include erratics, u-shaped valleys, moraines, chatter marks, striations, and cirques.
Cirques form at the head of a glacier, often on the northern slopes of mountain ranges. It begins with a preexisting depression that fills with snow and ice. That snow and ice gradually pry off pieces of rock from the base and sides of the depression gradually making it deeper. As the depression gets deeper, the snow and ice remain in shadow longer allowing glacier ice to form and start flowing.
Flow in this kind of glacier is down the backside of the depression, along the floor then out. The movement of the glacier speeds up the erosion on the sides and floor of the depression, creating an increasingly deep and sheer walled depression. After the glacier melts, portions of the seep sidewalls often collapse since they are no longer supported by the glacial ice. The depression often fills with water forming a lake that is called a tarn.
Three main characteristics are used to identify a cirque
1-A steep headwall and sides
2-A deep basin
3-A low ridge of bedrock or moraine on the 4th side
Sources:
Extent of Glaciation, Sierra Nevada Photos; (
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Atlas of California, 1979.
Glaciers of California, Guyton, 1998
Garry Hayes, Glaciation of the Sierra Nevada; (
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BSG 1996-2008; last modified: 14th Sep 2009; Glacial Erosion Landforms (Large-scale); (
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Corrie or Cirque Formation; (
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