 The Pacific Ranges in southwestern British Columbia are the southernmost subdivision of the Coast Mountains.It has been characterized by rapid rates of uplift over the past 4 million years unlike the North Cascades and has led to relatively high rates of erosion.The Insular Mountains on the coast of British Columbia have not yet fully emerged above sea level, and Vancouver Island and Haida Gwaii are just the higher elevations of the range, which was in fact fully exposed during the last ice age when the continental shelf in this area was a broad coastal plain.