Pleistocene Ice Age glaciers sculpted the Teton landscape over multiple glacial advances widening V-shaped river canyons into U-shaped glacial canyons, gouging out depressions filled by lakes today, sharpening high peaks, and filling the valley floor with outwash debris. The most recent advance, known as the Pinedale, lasted from roughly 50,000 to 12,000 years ago. Many hikers access the park's high country by traveling up glacial canyons such as Cascade, Paintbrush, Death Canyon and Granite. Look for features like glacially polished bedrock as you hike through these areas.