Mount-St-Helens Facts

Mount St. Helens threw a forest into Spirit Lake in 1980, and thousands of those logs still float there today. The landslide raised the lake about 200 feet and buried its outlet. To stop it bursting out and flooding the towns below, the Army Corps built a tunnel over a mile and a half long through a ridge, finished in 1985. It is still the lake's only drain, and it keeps buckling.

Mount St. Helens grew a brand-new glacier inside the crater its 1980 eruption left behind. Snow and rockfall piled up in the shade of the crater walls until the ice began to flow. In 2004 a new lava dome punched through it and cut it in half, but the two arms flowed around the dome and merged again by 2008. Crater Glacier is still creeping across the crater floor today.