1. 1998 Kelso, Washington, Landslide
Second largest suburban landslide in U.S. history
Exceptionally unstable geology
Troutdale Formation overlies Cowlitz Formation
The contact is a potential failure surface
FEMA-funded buy-out
137 homes damaged to some extent
127 homes to be purchased
Owners paid a maximum of 37.5% of house value

2. Kelso, WA Landslide: Locator Map

3. Kelso, WA Landslide: Overview

4. Upper Aldercrest: A Down-Scarp View

5. Upper Aldercrest: Small Scarp

6. Upper Aldercrest: A Plumb Well

7. Upper Aldercrest: Hanging Driveway

8. Upper Aldercrest: Downdropped House

9. Upper Aldercrest: Separated Section

10. Upper Aldercrest: Part of the Driveway

11. Upper Aldercrest: Rotated Structures

12. Upper Aldercrest: Hanging Structure

13. Upper Aldercrest: Missing Foundation

14. Upper Aldercrest: Separated Section

15. Upper Aldercrest: Torn & Twisted

16. Upper Aldercrest: Separated Masonry

17. Upper Aldercrest: An Abrupt Scarp

18. Upper Aldercrest: Hanging Roof

19. Upper Aldercrest: Tilted Plumb Well

20. Lower Aldercrest: Temporary Water

21. Lower Aldercrest: Moderate Movement

22. Lower Aldercrest: New Tension Crack

23. Lower Aldercrest: Side-Slope Shifting

24. Lower Aldercrest: Detached Garage

25. Lower Aldercrest: Unwanted Sunroom

26. Lower Aldercrest: A New Entryway

27. Lower Aldercrest: Minor Shifting

28. Lower Aldercrest: Natural “Tea”

29. Lower Aldercrest: Offset Curbing

30. Lower Aldercrest: Lowered Basket

31. Lower Aldercrest: Parallelogram Shift

32. Lower Aldercrest: Hold-Out Resident

33. Lower Aldercrest: Pressure Ridge

34. Lower Aldercrest: New Scarp

35. Lower Aldercrest: Halted Construction

36. Lower Aldercrest: Lateral Shift

37. Lower Aldercrest: Lateral Shift Detail

38. Lower Aldercrest: Tension Cracks

39. Lower Aldercrest: Makeshift Roadway

40. Lower Aldercrest: Parallelogram #2

41. Lower Aldercrest: First Floor Damage

42. Lower Aldercrest: A Side View