Artist's interpretation of what the snow covered Lolo Trail looked like in 1805. The Lolo was completed covered in snow when the troops crossed it going both east and west. Snow depths ranged from two feet to four feet. On their return march over the Lolo Bitterroots, Lewis wrote it was one of their few times they were forced to reverse march. After days of travels they were forced to return to the Nez Perce camp.