1 / 25

Scottish Avalanches

Scottish Avalanches. January 2010. What is an avalanche? What do you need for an avalanche to occur? How to avoid? What to do if caught? What to do if you see? Sources of information?. What is an avalanche?

theola
Télécharger la présentation

Scottish Avalanches

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Scottish Avalanches

  2. January 2010

  3. What is an avalanche? • What do you need for an avalanche to occur? • How to avoid? • What to do if caught? • What to do if you see? • Sources of information?

  4. What is an avalanche? • An avalanche is a rapid flow of snow down a slope, from either natural triggers or human activity.

  5. Avalanches can happen to you • Having accepted this, you have greatly reduced your chance of ever being involved in an avalanche.

  6. Three killed in avalanches in Scottish Highlands • Two climbers were killed in an avalanche on Ben Nevis, and a third died from his injuries after being swept away in another avalanche in Torridon, Wester Ross. • 30th December 2009

  7. Avalanche activity in the Pentlands • Full depth avalanche activity noted on the southern slopes of Carnethy Hill • Further minor sloughs noted on Scald Law • Creep lines noted on Turnhouse Hill • Significant week layers in the snow-pack identified at several locations 11th & 12th January 2010

  8. What do you need for an avalanche to occur? • Snow • Slope • Instability • Trigger

  9. Snow • How much? • Where is it lying? • Transportation • Slab (hard & soft) • Metamorphism (freeze thaw – sub zero) • Consolidation • The 24 hour rule

  10. Slope • Angle (30-45) • Orientation • Size • Terrain • Convex and Concave • Avalanche Classification

  11. Type of release Loose Slab

  12. Form of track Unconfined Channelled

  13. Position of sliding surface Full depth Surface

  14. Type of movement Airborne Flowing

  15. Instability • Sliding surface • Temperature • Firmness • Wet/Dry • Other • Significant difference in snow pack

  16. Trigger • Natural • Human

  17. How to avoid: Part 1 • Information • Weather reports • Avalanche reports • Personal reports (blogs, word of mouth etc) • Avalanche observations on the day • Snow pits = history

  18. How to avoid: Part 1 • By the time you set foot on the snow you should have a pretty good prediction of what conditions will be like, what level of hazard exists and where it is likely to be located. Your field observations modify and update this prediction and apply it to the specific case and/or location.

  19. How to avoid: Part 2 • Don’t go out • Do you have to cross? • Above and below • Route choice • Islands of safety • One at a time • Terrain traps

  20. Avalanche Risk Assessment • Could the slope avalanche? • Is the slope stable or not? • What could happen if it did avalanche? • Are conditions getting better or worse? • Is there anything you can do to prevent avalanche accident? • What is the likely hood of injury? • What can you do to minimise the risk? • Is the risk worth taking

  21. The four critical factors • Accumulation – is there sufficient snow on the slope? • Terrain – is the slope steep enough? Is there a convexity? • Weak layer – is a weal layer present in the snow-pack? • Trigger – are you going to go on the slope?

  22. What to do if caught in an avalanche? • Preparation • Delay departure • Get rid of kit • Shout • Swim or roll • Fight for the surface or an air pocket

  23. What to do if you see an avalanche? • Personal safety, check for further danger • Mark last location of victim • Count the survivors • Quick search • Thorough search • Send for help

  24. Sportscotland avalanche information service • Since 1988 • December to April • 5 areas • Actual reports for day • Forecasts for the following day • Weather forecast dependent • Weather wrong = avalanche forecast wrong • Do not rely on as only source of info • No substitute for what you see or find on the hill

  25. Sources of information • Books • A chance in a Million? Scottish Avalanches by Bob Barton & Blyth Wright • ISBN 0 907521 59 2 • Websites • http://www.sais.gov.uk/index.asp • http://en.wikipedia.org/wiki/Avalanche

More Related