In the photo you are looking at the back wall of the cirque occupied by Lake Ellen Wilson in Glacier National Park. A red line on the
topographic map marks the back wall of the cirque. The photo was taken approximately from where the camera is located on the map, looking
toward the northeast. Just a small portion of Lake Ellen Wilson shows in the foreground of the photo. The headwall of the cirque is quite
steep, although this is not readily apparent from the photograph. The closely spaced contour lines on the topographic map, however, clearly
show the steep back wall of the cirque. The semi-circular shape is evident in both the photo and on the topographic map. Lake Ellen Wilson
is an example of a tarn. Although no glacier exists here today, at one time a glacier formed here and flowed down the valley to the southwest.
The topographic map shows a waterfall just southwest of Lake Ellen Wilson and northeast of Lincoln Lake. The contour lines crossing the waterfall are similar in appearance
to the contour lines defining the cirque that Lake Ellen Wilson sits in: they are semi-circular in shape and closely spaced. Although the
shape and spacing of these contour lines makes this feature appear like a cirque, it is not a cirque. There is just one cirque for a particular
glacier and the cirque is located where the glacier begins. To identify a cirque for a glacier that still exists, look at the highest elevation
where the glacier starts. To identify a cirque where a glacier no longer exists, follow the river currently occupying the glacial trough
upstream to where the river starts and that is where you should find a cirque.