Snow Science at Mammoth MountainSnow Science at Mammoth Mountain

Ned BairNed Bair&&

Alex ClaytonAlex Clayton

Mammoth Mountain Ski PatrolMammoth Mountain Ski Patrol

The Weather and Avalanche Program

The Weather and Avalanche Program What are the geeks behind the computer up to?

The Weather and Avalanche Program What are the geeks behind the computer up to?

• Data Collection

The Weather and Avalanche Program What are the geeks behind the computer up to?

• Data Collection

- Weather Sensors & Daily Weather Observations

Wind, Temp, RH

Precip, Temp, RH

Not currently in Not currently in useuse

CRREL/UCSBCRREL/UCSB

The Weather and Avalanche Program What are the geeks behind the computer up to?

• Data Collection

- Weather Sensors & Daily Weather Observations

The Weather and Avalanche Program What 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)

The Weather and Avalanche Program What 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

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

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

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

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)

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!

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

“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

forecastingc. 1960

Drop Out 3February 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 eventTo 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

Avalanche Occurrence Charts 101

the new and improved way (hopefully)

Size Relative to Path

NR - No Result1 - Very Small, sluff2 - Small3 - Medium4 - Large5 - Major or Maximum

If there is No Result, circle NR

Avalanche Type

L - Loose SnowSS - Soft SlabHS - Hard SlabWS - Wet SlabWL - Wet Loose

Hard Slab = 1F or harder

TriggerAE - Hand ChargeAS - Ski CutAA - ArtilleryN - NaturalAC - Cornice DropAV - VehicleAO - Other

Number of Shots

Crown Depth

Slab Width

Path Length

Bed SurfaceS - In Storm LayerI - At Storm/Old InterfaceO - In Old LayerG - GroundU - Unknown

Avalanche StartT - Top of Starting ZoneM - Middle of Starting ZoneB - Bottom of Starting ZoneTK - TrackL - Skier’s LeftR - Skier’s RightC - Center

Avalanche ToeSZ - Starting ZoneTK - TrackTR - Top of Runout ZoneMR - Middle of Runout ZoneBR - Bottom of Runout ZoneU - Unknown

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.

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.

Questions?Questions?Questions?