2. Cascade Range Volcanoes Three Sisters Mount JeffersonMt. HoodMt.Adams Mt.Saint Helens Mt Rainier

5. Types of Volcanoes

8. California Volcanoes

9. Mount Lassen Helen Lake Elevation 10,457ft Most recent activity occurred in 1914-1917.

10. Lassen Erupts May 22, 1915

11. Mount Shasta Shastina Elevation 14,162ft Mt. Shasta debris avalanche covers an area of 450 square miles. 10 times the volume of the 1980 Mt. Saint Helens Eruption 2nd Tallest Peak in the Cascades

13. Mount Shasta and Haley’s Comet

14. Oregon Volcanoes

15. Crater Lake Wizard Island. A small cinder cone volcano. Mt. Mazama’s massive eruption created a caldera, forming Crater Lake Hillman Peak 8,126ft Highest point on the rim of the caldera Mt. Mazama was 10,800- 12,000ft prior to collapse

17. Mount Hood 11,239ft Most recent eruptive activity (1760-1810 A.D.) occurred just prior to Lewis & Clark’s visit in 1805.

18. Mount Hood from Portland Mt. Hood is located 75km Southeast of Portland, Oregon

20. Washington Volcanoes

21. Mount Adams 12,276ft Second in eruptive volume only to Mt. Shasta Third Tallest Peak in the Cascades

22. Mount Rainier 14,410ft Highest Peak in the Cascades Erupted as recently as the 1840’s Last large eruptions occured 1000 and 2300 years ago. Tacoma / Puget Sound

24. Mount Saint Helens Emerged from dormancy in May 1980 with a devastating eruption. Recently became active again in September 2004

25. The Bulge

26. USGS geologist: Dave Johnston

27. 9,677ft

32. Highest point of crater rim: 8,364ft (1,313ft lower)

33. Pyroclastic Flows Super-heated gases mixed with fine ash, cinders and volcanic bombs rush down the slopes of Mt. Saint Helens in the days following the large eruption.

34. David Johnston’s last know location

36. Before and After

38. May 18, 1980: Ashfall in downtown Yakima, WA

39. Smith Creek

40. Logging Mill on the Banks of the North Fork Toutle River

42. Pumice Plain Tributaries to NF of Toutle Creek 1980 2004 *Note evidence of erosion taking place on the pumice plain

43. Mudd River Creeks needed to downcut through the ash and pumice.

44. Mt. ShastaMt. Saint Helens

46. Cubic Kilometers of Ejecta from Historic Eruptions