the Stikine basin today, but to a much more limited extent. The Stikine Icecap, located in the Coast Mountains between the Stikine and Taku Rivers and the source of numerous glaciers descending to the Stikine valley, is one of the largest. Glacial activity strongly affects the geomorphology of the lower Stikine River. Due in large part to glacial silt or rock flour, the Stikine carries a heavy sediment load – some 16 million tonnes per year – continually expanding the large delta at the mouth of the river. In August 1979, a glacial lake outburst flood occurred at the Flood Glacier, releasing of water into the Stikine River, causing minor flooding as far as the mouth of the river. The Stikine's Grand Canyon likely formed after one such glacial period. Previously, the Stikine may have turned south around the present-day Klappan River confluence, and flowed down the valley of what is now the Iskut River. The river's former course may have been blocked by glaciers and it was forced to cut a new path west towards present-day Telegraph Creek. Another theory is that lava flows from the Mount Edziza volcanic complex were responsible for diverting the Stikine to its new course. History and culture First peoples The Stikine River creates one of the only natural passages through the Coast Mountains, and for thousands of years it has been used as a trade route by indigenous peoples. The river has great cultural significance for indigenous peoples; the adjacent headwaters of the Stikine, Skeena River and Nass Rivers in the Klappan Range are known to the Tahltan as Klabona, the Sacred Headwaters. The lower Stikine and Iskut rivers are home to "a high number of aboriginal cultural heritage sites, including old villages, legend sites and traditional fishing areas." Archeological sites in southeast Alaska suggest that the first humans arrived in this region about 10,000 years ago, around the end of the last glaciation, when ice dams that had previously blocked the Stikine were receding. According to Tlingit legend, their ancestors lived in the interior thousands of years ago and migrated to the coast via the Stikine River. However, a glacier (perhaps today's Great Glacier) blocked their passage down the river. Tribal elders explored a tunnel through which the river flowed under the glacier, expecting not to return from this dangerous mission. To their surprise they discovered a way through, and their people