The 22 000 square kilometre Kluane National Park is set like a jewel in the southwestern corner of the Yukon between northeastern British Columbia and the tidewaters of the Alaskan panhandle. Much of the park's 129 kilometre northern boundary is made up of the Alaska Highway and the Haines Road. The Alsek River, known for its big water rapids created by the tremendous volume of water it drains from the St. Elias Mountains, is so swift it appears that native people have entirely avoided using it for travel or trade routes. Lowell Glacier's immense and spectacular advances and retreats have periodically blocked the Alsek causing flooding that over the centuries has greatly affected the vegetation and wildlife in the low-lying valleys.