Mount Robson (3954 meters, 12,973 feet) is the tallest mountain in the Canadian Rockies. I've included this cropped photo to illustrate the size of the glacier on the summit of Robson. It is about 2,700 vertical feet from the summit down to the point of rock at the lower right corner of the photo.
But this glacier is dwarfed by the the massive Robson Glacier on the other side of the mountain, which averages over 2 km wide and is about 7 km long. A large part of the total area of Mt. Robson is covered with very active glaciers. From the Toporama map, I estimate that the total area of glacier on Robson is 35 to 40 square kilometers.
They say that Mt. Robson is so tall and massive that it creates its own weather. Here we see just a trace of that effect as a thin cloud forms over the summit.
This image is a "100% crop" of a small part of a much larger photo of the entire mountain and valley. This picture was taken with a Canon Rebel XT and the EF-S 17-55mm f2.8 zoom, which is a very fine lens.
