A Short History of the White River Crossing: Battling the Demon of Mount Hood

1. A Short History of the White River Crossing: Battling the Demon of Mount Hood Tom DeRoo Mt. Hood National Forest

5. RoadsandTrailsaroundMt. Hood

6. Debris flows: • Channelized landslide • Mixture of water, soil, rock • Consistency of wet concrete • Often contains wood debris • Typically travels at 10 – 20 mph

7. Recent debris flows onMt. Hood

8. Number of Major Mt. Hood Debris Flows per Year, 1975-2006

9. Debris flows are frequent on Mt. Hood because the conditions for their formation are nearly ideal. • Confined channels with steep gradients • Very steep side slopes • Abundant loose soil and rock • Occasionally abundant water

11. Sources of water for Mt. Hood debris flows • Glacier meltwater • Summer/fall storms • Rain-on-snow events • Rapid snowmelt • Combination of above

12. Recent debris flows onMt. Hood

14. White River Valley Cross Sectionlooking downriver Green Apple Creek White River Mineral Creek

15. A short history of the Mt. Hood Loop Highway • Shown as “proposed” on 1916 map • Construction completed in 1925 • Last segment crossed White River

16. A short history of the White River Crossing • Shown as “proposed” on 1916 map • Construction completed in 1925 • Last segment crossed White River • August 1926 debris flow buries approach

17. A short history of the White River Crossing • Shown as “proposed” on 1916 map • Construction completed in 1925 • Last segment crossed White River • August 1926 debris flow buries approach • October 1926 debris flow damages bridge

18. A short history of the White River Crossing • Shown as “proposed” on 1916 map • Construction completed in 1925 • Last segment crossed White River • August 1926 debris flow buries approach • October 1926 debris flow damages bridge • 1927 debris flow buries bridge

19. A short history of the White River crossing • Shown as “proposed” on 1916 map • Construction completed in 1925 • Last segment crossed White River • August 1926 debris flow buries approach • October 1926 debris flow damages bridge • 1927 debris flow buries bridge • Bridge replaced in 1929

20. “There is White River Valley which is almost annually laid waste for half to a mile in width leaving a desert of boulders, gravel and sand, whose river almost annually rebels at human intervention and demoniacally rips out sections of the highway bridge which crosses it.” (U.S. Forest Service, Study of Mount Hood Area, 7-8-1929)

21. “There is White River Valley which is almost annually laid waste for half to a mile in width leaving a desert of boulders, gravel and sand, whose river almost annually rebels at human intervention and demoniacally rips out sections of the highway bridge which crosses it.” (U.S. Forest Service, Study of Mount Hood Area, 7-8-1929)

22. A short history of the White River Crossing • 1920’s – 3 debris flows • 1930’s – 3 debris flows • 1940’s – 3 debris flows • 1950’s – 3 debris flows • 1960’s – 5 debris flows • 1970’s – 1 debris flow • 1980’s – 1 debris flow

23. A short history of the White River Crossing • 9-3-1998: debris flow, 220,000 CY, partially filled in channel • 10-1-2000: debris flow, 440,000 cubic yards, filled opening under bridge • 11-7-2006: debris flow, 600,000 cubic yards, buried bridge

24. White River October 1, 2000 prolonged high temperatures rapid glacial melt intense rain event

28. White River Bridge – pre-event

29. White River Bridge – post-event

30. What to do about the demon of Mt. Hood?

31. What to do about the demon of Mt. Hood?(same question asked in 1929)

32. White River November 7, 2006 high temperatures record rain event

33. Precipitation and Freezing Levels

34. Daily Precipitation