The worst-case scenario for an eruption is a large pyroclastic flow , similar to that which occurred in the 1980 eruption of Mount St. Helens . Since there is ice , such as Whitney Glacier and Mud Creek Glacier , lahars would also result . Ash would probably blow inland , perhaps as far as eastern Nevada . There is a small chance an eruption could result in a collapse of the mountain , as happened when Mount Mazama in Oregon collapsed to form what is now called Crater Lake , but this is of much lower probability
1980 eruption of Mount St. Helens
1980 eruption of Mount St. Helens
Mount Shasta