Be Geohazard Aware!
Recent research has improved our understanding of Mount Rainier, an active volcano. Active steam vents, periodic earth tremors, and reported historical eruptions provide evidence that Mount Rainier is sleeping, not dead. Seismic monitoring stations around the mountain should provide days or weeks of advance warning of impending eruptions. However, other geologic hazards like debris flows, glacial outburst floods, and rockfall can occur with little warning.
Detailed geohazard information is available at park visitor centers and from scientists at the USGS Cascades Volcano Observatory.
The more time you spend in an area where there are geologic hazards, the greater the chances that you could be involved in an emergency event. While most people consider the danger to be relatively low, you must decide if you will assume the personal risk of visiting these potentially dangerous locations. When you arrive in the park, be sure to review posted geologic hazard, evacuation, and escape information. Longmire, Carbon, and the campgrounds at Cougar Rock, Ohanapecosh, and White River are all vulnerable to geologic hazards. Many trails pass through geohazard areas. Remember, ANY river in the park is at risk of a debris flow.
Rising water level, shaking ground and a rumbling noise may signal a debris flow or lahar. If you are near a river and notice:
- A rapid rise in water level
- Feel a prolonged shaking of the ground
- Hear a roaring sound coming from up valley (often described as the sound made by a fast–moving freight train)
Geohazard Warning Sirens
Geohazard sirens are located at high visitor concentration locations along the Nisqually river including Cougar Rock Campground, Longmire, and Nisqually Entrance. If you hear the siren during your visit, head uphill, away from rivers.
Listen to the Geohazard Siren.