Snow Science at Mammoth Mountain

1. Snow Science at Mammoth Mountain Ned Bair & Alex Clayton Mammoth Mountain Ski Patrol

2. The Weather and Avalanche Program

3. The Weather and Avalanche ProgramWhat are the geeks behind the computer up to?

4. The Weather and Avalanche ProgramWhat are the geeks behind the computer up to? • Data Collection

5. The Weather and Avalanche ProgramWhat are the geeks behind the computer up to? • Data Collection - Weather Sensors & Daily Weather Observations

6. Wind, Temp, RH Precip, Temp, RH Not currently in use CRREL/UCSB

9. The Weather and Avalanche ProgramWhat are the geeks behind the computer up to? • Data Collection - Weather Sensors & Daily Weather Observations

10. The Weather and Avalanche ProgramWhat are the geeks behind the computer up to? • Data Collection - Weather Sensors & Daily Weather Observations • - Lots of data cleanup (thanks to the revered geeks of MMSP’s past)

11. The Weather and Avalanche ProgramWhat are the geeks behind the computer up to? • Data Collection - Weather Sensors & Daily Weather Observations • - Lots of data cleanup (thanks to the revered geeks of MMSP’s past) • Avalanche Occurrence Charts

12. Why do we fill out Occurrence Charts?(Especially when nothing slides?)

13. Why do we fill out Occurrence Charts?(Especially when nothing slides?) • Legal Documentation • In the event of a post control release, we have evidence that we followed our standard protocols

14. Why do we fill out Occurrence Charts?(Especially when nothing slides?) • Legal Documentation • In the event of a post control release, we have evidence that we followed our standard protocols • Knowledge • Tracking Ax occurrences improves our understanding of the processes in our snowpack

15. Why do we fill out Occurrence Charts?(Especially when nothing slides?) • Legal Documentation • In the event of a post control release, we have evidence that we followed our standard protocols • Knowledge • Tracking Ax occurrences improves our understanding of the processes in our snowpack • Keeping tabs on where weak layers are persisting (i.e.. Paranoid 3/4)

16. Why do we fill out Occurrence Charts?(Especially when nothing slides?) • Legal Documentation • In the event of a post control release, we have evidence that we followed our standard protocols • Knowledge • Tracking Ax occurrences improves our understanding of the processes in our snowpack • Keeping tabs on where weak layers are persisting (i.e. Paranoid 3/4) • Studying which weather conditions do not cause avalanches can be just as useful as those which do!

17. Why do we fill out Occurrence Charts?(continued) • Forecasting • We use our weather and avalanche data in house as well as giving it to researchers developing computer models for predicting avalanches

18. “I never used to think of tide forecasts as prediction at all - I used to think of them as statements of fact - but of course, you are predicting. Tides are actually just as complicated as the atmosphere.” • - Edward Lorenz, • father of chaos theory & modern weather • forecasting • c. 1960

19. Drop Out 3 February 21, 1986 6:40am Class 5 Hard Slab Avalauncher, 7 shots 1800 Vertical Feet 125-175 Feet Wide 258 Inch (21.5 Foot) Crown Class 5 - Extreme event To the ground with a typical mid-season snowpack, full length and width of the path Only 7 other avalanches that day. All ≤ Class 2 Buried Chair 23 Base

23. Avalanche Occurrence Charts 101the new and improved way (hopefully)

29. Size Relative to Path NR - No Result 1 - Very Small, sluff 2 - Small 3 - Medium 4 - Large 5 - Major or Maximum

30. If there is No Result, circle NR

31. Avalanche Type L - Loose Snow SS - Soft Slab HS - Hard Slab WS - Wet Slab WL - Wet Loose

32. Hard Slab = 1F or harder

33. Trigger AE - Hand Charge AS - Ski Cut AA - Artillery N - Natural AC - Cornice Drop AV - Vehicle AO - Other

34. Number of Shots

35. Crown Depth

36. Slab Width

37. Path Length

38. Bed Surface S - In Storm Layer I - At Storm/Old Interface O - In Old Layer G - Ground U - Unknown

39. Avalanche Start T - Top of Starting Zone M - Middle of Starting Zone B - Bottom of Starting Zone TK - Track L - Skier’s Left R - Skier’s Right C - Center

40. Avalanche Toe SZ - Starting Zone TK - Track TR - Top of Runout Zone MR - Middle of Runout Zone BR - Bottom of Runout Zone U - Unknown

41. Tips for better Ax Occurrence Charts • Don’t use pencil. These are legal documents and all the same rules apply as to incident reports. They are a reflection of your professionalism. • Fill them out promptly, memories fade quickly. As soon as possible, sit down and jot down some notes, it will make filling out the chart much easier later. • If you get any significant results or were unable to observe your results, try to spin back through ASAP to get a closer look.

42. Tips for better Ax Occurrence Charts • Complete a chart for each team, paper is cheap, confusion is expensive • Don’t pass the buck to your mule, they often lack the experience to identify individual paths, relative size, etc. • The documentation is the responsibility of the licensed blaster. However, two brains are better than one and sitting down with your mule is an important part of their continuing training.

43. Questions? Questions?