Term
| Direct Effects of Avalanches |
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Definition
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Term
| Indirect Effects of Avalanches |
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Definition
| - tsunami generation if the avalanche enters a lake |
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Term
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Definition
| - internal resistance to movement |
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Term
| Safety Factor of an Avalanche |
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Definition
Shear strength/shear stress
- if safety factor<1, the slope is unstable |
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Term
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Definition
| - force causing movement parallel to slope; increases w/ slope angle |
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Term
| Def. Loose Snow Avalanche |
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Definition
- surface phenomenon
- easier to get out of |
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Term
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Definition
- more dangerous than loose slow
- slab detaches and slides down
- does not remain intact
- very hard to get out of due to huge mass and force |
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Term
| What are the features of the head of the avalanche? |
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Definition
- 2X as thick as the body
- encounters friction with the atmosphere which leads to mixing of the snow
- as a result the front moves slower than the rest
- in slab avalanches it is more dangerous |
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Term
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Definition
comes from slabs
- 5-10m in height
- collision of particles is why the avalanche flows
- interior of the flow has a high density core near the base
- particles collide resulting in heat (friction)
- when the flow stops the melted sections can freeze and set like concrete |
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Term
| Describe Airborne powder snow avalanches |
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Definition
- can have a velocity of over 100 m/s
- can be over 100 m thick
- thick but dilute therefore move much quicker
- newly fallen snow becomes incorporated |
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Term
| Describe Powder Snow Avalanche Runout Area |
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Definition
- flow around obstacles while flow avalanches do not
- when they hit a barrier the lower dense portion is stopped while the dilute cloud moves like a fluid over/around the obstacle |
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Term
| Are there more or less avalanches happening in Canada? Why? |
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Definition
- more avalanches
- more people doing more snow related activities
- the most common triggers are human related and not natural
- dry slab most common
- leeward slopes are the most stable protected by the wind |
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Term
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Definition
- avoid steep slopes and gullies
- setting off explosive charges to artificially induce avalanches and remove unstable snow can prevent avalanches |
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Term
| Name and describe the types of engineered works that are used to mitigate avalanches. |
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Definition
Reforestation- stabilizes slopes and snow
Terracing- in avalanche prone zones without trees
Deflectors- to divert the flow
Arresters- slow/ stop, but be high enough or they can accelerate the intensity
Splitters- redirect around and single object
Mounds- used to slow flowing snow at the end of the runout zone
Snowsheds- allow the avalanche to pass over a structure |
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