Everyone in the northwest now understands that a dormant volcano can wake with incredibly destructive power. Scientists tell us that any of the dormant Cascade Volcanoes can become active again sometime in the future with the same or greater power than Mt. St. Helens. Mt. Rainier is particularly dangerous because it is so close to the heavily populated Puget Sound area. However, a volcano doesn't need to erupt with ash and magma to wreak destruction on the landscape. Natural forces are eroding the sheer slopes of volcanoes, weakening the igneous rock.
Gravity can then pull down altered rock faces and start a rock slide.
Mixed with snow and water, the slide can turn into a mudflow or slurry and travel many miles, destroying everything in its path.