quartz/content/notes/avalanche.md
2023-01-08 14:20:15 +13:00

145 lines
3.3 KiB
Markdown

---
title: "avalanche"
tags:
-
---
link: https://www.youtube.com/watch?v=-luspmL_f1o
- Lower risk
- Avoid avi terrain
- safety gear
- what to consider
- using a guide
Reducing risk
- total avoidance (dont go backcountry at all)
- avoidance lite (avoid all avalanche terrain)
- recognising risk, accepting it, minimizing exposure
- use bulletin
avoidance
- stay in bounds/on piste
- use low angle slopes
- steep: 30-45 degrees
minimize exposure to risks
- know if you are in avalanche terrain
- maps, guidbooks, photos
- clinometers
- _quality_ level 1 course
Use the bulletin forecast
- low
- moderate : natural avalanches not likely, man made avalanches possible if you ski in the wrong spot
- considerable: if you ski in the wrong spot, human triggered avalances are likely
no overhead hazard: not below a large face or something
avalanche problem:
- persistent weak layer
- wind drifted snow
whoomps under skis: collapsing snow, avalanches likely
## Video 2
link: https://www.youtube.com/watch?v=1r0YIgdjm6M
lots of different types of avalanche. loose vs slab, wet vs dry.
usually: strong snow over weak snow.
strong: often wind effect: ltighly bonded grains
weak: light snow with no wind and cold clear nights
important: slope angle
## Snowpack tests
link: https://www.youtube.com/watch?v=OvwhuP4qtQg
- compression test
- locating instabilities near surface
- 30(upslope not horixontal) x30cmx110cm ()
- ![](https://i.imgur.com/ebmXC6M.png)
- tap 10 times with finger tips
- mark factures as easy
- level column
- tap 10 times with finger tips from elbow
- level
- tap with hand or fist from shoulder
- ![](https://i.imgur.com/2sCLTuz.png)
- ![](https://i.imgur.com/YT6hWpT.png)
- facture types video: http://vimeo.com/30996756
- deep tap test
- similar to compression test but tests only for weak persistent layer relatively deep in the snowpack
- extended column test
- same as compresion test but 90cm wide not just 30cm
- ![](https://i.imgur.com/itugyJ1.png)
- rutschblock test
- ![](https://i.imgur.com/FnocAmt.png)
- propagation saw test
- shovel shear test
- hand shear test
equipment
- shovel
- probe
- snow saw
- ruler
- cord
## uptracking and route selection
link:https://www.youtube.com/watch?v=RAXgSoSUD3Y
avalanche triangle: snowpack, terrain, weather.
terrain
- ![](https://i.imgur.com/31KOLSD.png)
- 5 red flags: "natures freebies"
- recent avalanches
- shooting cracks
- recent wind loading
- recent snow
- thaw, snow snails
- debris in creeks
snowpack
- ![](https://i.imgur.com/huT2fni.png)
weather
- ![](https://i.imgur.com/7zMk1mx.png)
alptruth
- ![](https://i.imgur.com/EIoOczr.png)
stay far apart so you dont all get trapped.
uptracking
- ![](https://i.imgur.com/fs8b8Vm.png)
- use google earth
steepness
- ![](https://i.imgur.com/TNsm8Wd.png)
- caltopo
- hill map
100 with hand vs 1 snow pit
human factor
- familiarity: assuming this are safe because they have been in the past
- acceptance: allowing desire for acceptance (of others) to override decision making process
- consistency: fear of appearing indecisive,
- expert halo: deferring automatically to the expert
- tracks/scarcity:allowing desire to have your day out to influence decisions
**develop a routine**
## Weather and snowpack: slab avalanche formation
avalanches