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5. 5 U.S. Avalanche Fatalities by Activity 1950/51 to 2000/01 57 95 27 24 58 130 138 climbers bc skiers lift skiers (ob) lift skiers (ia) snowboarders snowmobilers misc. recreation

6. 6 U.S. Avalanche Fatalities by Activity 1993/94 to 2000/01 23 73 22 1 14 31 29 climbers bc skiers lift skiers (ob) lift skiers (ia) snowboarders snowmobilers misc. recreation

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8. 8 TYPE OF RESCUE (US) 1950/51-1998/99 Self Rescue Companion Rescue Organized Rescue ALIVE49 (17%)186 (64%)57 (20%) DEAD84 (22%)306 (78%)

9. 9 With avalanches you have three choices… 1.Avoid avalanche terrain 2.Learn about avalanches, minimize your risks 3.Roll the dice (or pull the lever!)…

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12. 12 POINT RELEASE aka SLUFFS

13. 13 Starting zone Track Runout zone SLAB AVALANCHE

14. 14 Slab Avalanche:  Crown face  Bed surface  Flanks  Stauchwall

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16. 16 A slab is just a cohesive mass of snow

17. 17 Slab avalanches can propagate for long distances

18. 18 WET SLAB

19. 19 KEY FACTORS  Terrain  Weather  Snowpack  “Human Factors”

20. 20 TERRAIN Is the terrain capable of producing an avalanche?

21. 21 RECOGNIZING AVALANCHE TERRAIN Factors to consider:  Slope angle  Slope size and consequences  Slope shape  Vegetation/trees  Runout  Aspect w/respect to wind  Elevation

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23. 23 Slope Angles 60 deg 45 deg 30 deg 15 deg 0 deg

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26. 26 Slope Shape convexity concavity

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28. 28 “Size doesn’t matter”

29. 29 Vegetation damage is a sure-fire indicator of avalanche terrain!

30. 30 Vegetation damage is also a helpful indicator of runout!

31. 31 TERRAIN TRAP!!

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35. 35 INDEPENDENCE SLIDE, BIG TIMBER, MT February 24, 2001

36. 36 38° 36° 40° Trigger Point Burial Point

37. 37 TRIGGER POINT BURIAL 500 FOOT FRACTURE 800 FOOT RUNNING DISTANCE

38. 38 2 TO 3 FEET DEEP

39. 39 CROWN FACE PROFILE NEW SNOW WIND SLAB NEAR-SURFACE FACETS CRUST RELATIVE HARDNESS DEPTH IN INCHES 4332640

40. 40 Burial Point

41. 41 Victim was buried 5-6 feet deep!

42. 42 WEATHER Is the weather affecting the snow stability?  Snow and Rain  Wind  Temperature

43. 43 Wondering what the winter will be like?

44. 44 More Snow Equals More Avalanches!!

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51. 51 LIONHEAD AREA, WEST YELLOWSTONE, MT April 4, 2001

52. 52 Victims Track

53. 53 Crown is 6-8 feet deep

54. 54 PATH Snowmobile Victim 75 Feet

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56. 56 BURIED 2 FEET DEEP

57. 57 SNOWPACK Could the snow slide?

58. 58 Stressvs.Strength

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60. 60 Surface Hoar

61. 61 Faceted Snow

62. 62 HENDERSON MOUNTAIN, COOKE CITY, MT February 4, 1992

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70. 70 HUMAN FACTOR Are you willing to make an objective assessment of the avalanche danger?

71. 71 CALL YOUR LOCAL AVALANCHE CENTER

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73. 73 Pay Attention To OBVIOUS Signs of Instability These include collapsing, cracking or “whumphing” of the snow, and…

74. 74 Recent avalanche activity

75. 75 Snowmobiler highmarking adjacent slope Investigating avalanche from day before

76. 76 Yesterday’s Slide Path Everyone is facing uphill, engines off, with nowhere to run.

77. 77 Investigating crowns can give you valuable information about the snowpack!

78. 78 Test Small Slopes

79. 79 Poorly executed highmark

80. 80 Descending a slope from the top is safer than riding up from the bottom

81. 81 Ride the slope one at a time!!

82. 82  63% of snowmobile avalanche accidents occur while highmarking  Bottom Line: if you’re going to highmark don’t expose more than one rider at a time on the slope

83. 83 Don’t ride up to help out your stuck buddy!!

84. 84 CARRY RESCUE GEAR!! Or better yet…make sure your PARTNER has rescue gear!

85. 85 KEY POINTS Ride the slope one at a time. Don’t ride up to help dig out your stuck partner.  Ride the slope one at a time. Don’t ride up to help dig out your stuck partner.  Recent avalanches are an obvious sign of instability, so don’t play on adjacent slopes blindly.  Test lots of small slopes on your way in and get off the packed trail as much as you can. Get off your machine and walk around occasionally.  Riding a slope from the top down is a safer option than from the bottom up, because you are facing a better direction if anything goes wrong.

86. 86 If the goal is to highmark then gather as much information as possible on initial passes by riding low and fast and not getting stuck. Turn away from the center of the slope.  If the goal is to highmark then gather as much information as possible on initial passes by riding low and fast and not getting stuck. Turn away from the center of the slope.  If you’re at the bottom waiting your turn and can’t avoid sitting in a big runout zone, keep your machines running and pointed away from the slope for a fast escape.  Carry rescue gear on you and know how to use it.

87. 87 Putting it all together… Recognize that patterns exist based on elevation, aspect and slope angle!

88. 88 SAFE TRAVEL Slope angle, aspect with respect to sun and wind, consequences, slope shape, trees, runout, elevation, patterns of avalanche activity…

89. 89

90. 90 Created by:  Gallatin National Forest Avalanche Center  US Forest Service National Avalanche Center Photographs courtesy of: Doug Chabot, Tom Evans, Ron Johnson, Lance Reik,Karl Birkeland, Bruce Tremper, Scott Schmidt, Ian McCammon, Don Bachman, Doug Fesler/Jill Fredston and CAIC. Special thanks to Doug and Jill for using their Terrain/Weather/Snowpack method from Snow Sense.