Everyone has some idea of what happens when a volcano erupts, but how much does the average person really know about what might happen were Mount Rainier to erupt? The beautiful volcano may sit in the heart of a national park, and despite being covered in lovely meadows, amazing hiking trails, and wonderful animals, it's still a volcano - and there's a chance it could blow its top just like Mount Saint Helens did in 1980.
The good news: This probably won't happen anytime soon, and even if it does, there are agencies and measures put in place to ensure the number of casualties are low to none. Even when Mt. St. Helens erupted, there was enough warning to limit the casualties to a relatively low 57, and Mt. Rainier is covered with sensors and equipment to offer up a warning long before the volcano erupts.
That being said, the devastation an eruption would cause is relatively well-known. Thanks to other eruptions like the aforementioned, geologists and volcanologists have determined the most likely route lava, lahars, and a pyroclastic flow would take. This knowledge has helped determine the best courses of action to ensure the safety of everyone in Washington should an eruption occur.