These tephra layers are exposed along a gully eroded into an alpine meadow on the east flank of Mount Rainier (snow-covered cone in distance). The meadow is located above Frying Pan Creek in the Summerland area. More than 40 layers of tephra less than about 10,000 years old have been identified by scientists in Mount Rainier National Park. Ten tephra layers originated from Mount St. Helens, 80 km south of Mount Rainier, and 1 layer came from Mount Mazama (Crater Lake) in Oregon, 220 km south. Mount Rainier erupted 11 layers of pumiceous tephra and at least 25 layers of tephra composed of dense particles. The pumice layers were produced by explosive eruptions of gas-rich magma whereas the others were probably erupted by less explosive gas-poor magma or caused by steam explosions or by the ash clouds from pyroclastic flows.