OS 21000 Snow Science
Final Exam
Total points 60p.
(Represents 10/100 points in the total course work)
Answer the following questions in a short answer format. The exam is due on
Wednesday 12/9 at 6pm. Email the answers to elatosuo@alaskapacific.edu
(preferred) or leave a hardcopy in my box outside the office.
If you have any questions, please email me.
Enjoy the test,
Eeva
Part A: Saturday December 5, 2009. The day before the ski tour.
You are planning to ski Sunburst at Turnagain Pass area with your two friends tomorrow.
Human factor analysis (1p):
Who are your friends, what is their experience and training with avalanches and backcountry skiing?
In my party will be Jenny, Jack, and Tanner. These are individuals that possess avalanche rescue training
and I feel comfortable traveling with them in the backcountry.
Mark in the following chart where you think you and your partners are on this chart.
Chances of being caught in an avalanche (according to Dale Atkins, CAIC)
Avalanche Training
Advanced
0%
0%
43%
Some training
0% We are here
2%
33%
No training
6%
6%
10%
Skill in traveling
Novice
Intermediate
Advanced
Trip plan (10p):
1. Please provide a trip plan with a common trip goal starting and finishing at the trailhead.
2. Mark your planned route and trip legs on the provided map.
You get hold of the current weather forecast and avalanche advisory to guide your planning (see the
attached texts) (10p.)
3. Mark and number the areas of your chosen route that you are concerned about. Write a list of
explanations why you are worried about these areas.
4. Decide on an alternate plan for the day of touring from the same parking lot. Mark it on the map
as an alternate route.
Most current avalanche advisory for Chugach National Forest:
Current Advisory
Saturday, December 5th 2009
Created: Dec 5th 6:18 am
Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche
Information Center on Saturday December 5th at 7 am. This will serve as a general backcountry
avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory
does not apply to highways, railroads, or operating ski areas).
ANNOUNCEMENTS
All areas designated for snowmachines (except Placer and 20 Mile) on the Chugach National Forest are
open. We are monitoring the snow at Placer and 20 Mile and will open those areas as soon as there is
enough snow.
WEATHER ROUNDUP
Hindcast (Last 24 hours)
3800’ -Sunburst Wx StationTemp: 25 (8 degrees warmer than yesterday)
Wind: averaged light to moderate 8-10 mph out of the ESE with gust of 24-40 mph
1800’-Center Ridge Wx StationPrecip: 0 inches of water and 0 new snow
minus 3” of total snowpack due to settlement. Total snow depth is 67 "
Temp: 25 degrees (3 degrees warmer than yesterday)
3400’-Frezno Ridge Wx StationTemp: 28 degrees (11 degrees warmer than yesterday)
Wind: averaging 8-11 mph with gust 19-24, northwest.
1200’-Summit Lake Wx StationPrecip: 0 inches of water and 0 new snow
Total snow depth is 28 ", (down 1 due to settlement)
Temp: 19 degrees
Nowcast (OTW)
Temperatures warmed back up a bit overnight. Temperatures range from 24 to 29 degrees with Summit
Lake the out lier,19 deg. Winds are light to moderate out of the southeast.
The satellites show high cloud cover and the radars show no precipitation. Expect pretty mellow
weather again today. Greybird. A 1055 mb high is sitting in central AK deflecting lows to our north.
Expect this blocking high to be in place through most of the week.
Forecast
AKZ125-040100WESTERN PRINCE WILLIAM SOUNDINCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKST SAT DEC 5 2009
.TODAY...MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. HIGHS IN THE
MID 20S TO LOWER 30S. NORTH TO EAST WINDS 5 TO 15 MPH. THROUGH
PORTAGE VALLEY AND TURNAGAIN ARM...WIND 15 TO 30 MPH.
.TONIGHT...MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. LOWS IN THE
MID 20S TO LOWER 30S. NORTH TO EAST WIND 10 TO 20 MPH EXCEPT
SOUTHEAST 25 TO 35 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.
.SUNDAY...MOSTLY CLOUDY WITH ISOLATED SNOW SHOWERS IN THE
MORNING...THEN PARTLY CLOUDY IN THE AFTERNOON. HIGHS IN THE 30S.
NORTH TO EAST WIND WIND TO 15 MPH EXCEPT SOUTHEAST WIND 15 TO 30 MPH
THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.
.SUNDAY NIGHT...MOSTLY CLEAR. LOWS IN THE LOWER 20S TO LOWER 30S.
VARIABLE WIND TO 10 MPH.
.MONDAY...MOSTLY SUNNY. HIGHS IN THE UPPER 20S TO MID 30S. VARIABLE
WIND TO 10 MPH.
TEMPERATURE / PRECIPITATION
SEWARD 33 28 36 / 20 20 20
GIRDWOOD 31 25 32 / 0 20 0
AVALANCHE DISCUSSION
Todays conditions are very similiar to yesterday. Natural avalanches will be unlikely, but small human
triggered avalanches are still possible in specific areas like rocky areas near wind hammered ridges or
anywhere the snowpack was tapered from the recent high wind event. Due to a current deep instability,
there is still a chance for large avalanches in isolated areas. Due to time and lack of significant weather,
the avalanche danger remains MODERATE today. MODERATE is defined as: Heightened avalanche
conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
We have not seen or heard of any natural or human triggered avalanche activity since Tuesday's storm.
The usual suspect areas ripped out on Tin Can Ridge (south face), Sunburst (south face), and Magnum
(west face) during that period. Since the snows subsided on Tuesday we have seen nice settlement and
cooling temps. This process is making a more stable snowpack. The main area of concern lies at the
ground where we still see faceted crystals from early November. This weak layer of snow is everywhere,
from Anchorage to Seward. This is a typical setup for early winter in our area. Time should eliminate the
reactivity of this deep weak instability. Both the lack of a temperature gradient and the pressure of the
overlying snowpack will assist in this process. Areas we need to stay on our toes include thinner
snowpacks. The sphere of influence (depth that a traveler's weight will affect the snow) is about 3-4 feet
deep for skiers and boarders, and 5-6 ft for snowmachiners. Snowpacks deeper than this have a stability
advantage over shallower snowpacks. The sphere of influence will effect the weak faceted snow on the
ground in shallower snows. Summit Lake, areas around Johnson Pass (Lips, Cornbiscuit, Silvertip) and all
other areas with 3-5 foot snowpacks will have increased avalanche hazard.
One more feature of concern includes ridge tops were wind is building wind slabs. These wind slabs are
present and could take a person for a ride. These areas are considered complex terrain and careful
routfinding needs to be executed.
As you plan your weekend keep this in mind. Shallower snow areas may bump the danger rating up to
CONSIDERABLE. Take your time assessing shallower snowpacks. Send us your observations if you find
good or poor stability. We have limited beta on Summit, Lost Lake, Johnson, and upper Glacier Valley.
There are also glide cracks opening up all over the place. These will continue to get wider and wider.
People and dogs have fallen into these glide cracks in the past, and they can be very difficult to get out
of.
This concludes today's advisory. The next advisory will be December 6th. Thanks and have a great day.
General Snow Conditions for the Turnagain Area - Updated As Necessary
Date
Snow Condition Update
Thursday,
December 3rd
2009
NATURAL AVALANCHES
Medium sized Natural Avalanches were observed on Tincan (see Photo Gallery) and
reported on Sunburst and Magnum. Some of these probably failed on the facets on the
ground during the height of the storm on Tuesday 12/1/2009.
Wednesday,
December 2nd
2009
Parking Lot Snow Measurements for Tuesday 12/1/09:
Tincan Lot: 24-28 inches of new wet snow
Motorized Lot: 22 inches of new snow
Sunburst Lot: 10 inches of new very wet snow
Johnson Pass Trailhead: 5 inches of new very wet snow
Sunday,
Parking lot storm snow totals since Monday 11/23/09
November 29th Eddies Lot: 27" new snow
Motorized Lot: 31" new snow
2009
Sunburst Lot: 20" new snow
Johnson Pass Trailhead: 14" new snow
Saturday,
2 feet of snow has fallen in the last 24 hours in many areas covered by this advisory.
November 28th Most of that fell yesterday. 4 to 6 inches fell last night. 2 to 3 inches of water
equivalent fell in this storm. Snowfall totals for the two day storm range from 1 to 2
2009
feet at sea level and 3 to 4 feet above 500 ft.
Monday,
Eddies Parking Lot: 12" new wet snow (rain/snow mix)
November 23rd Motorized Parking Lot: 24" new snow
Sunburst Parking Lot: 16" new snow (rain/snow mix)
2009
Johnson Pass Trailhead: 3" new snow
Natural avalanches and human/triggered avalanches observed in Girdwood Valley and
Turnagain Pass.
Thursday,
Nov. 12, 2009 - 4-6 inches of new snow yesterday over the advisory area. Center Ridge
November 12th station at 1000 ft in Turanagain Pass is reporting 19 inches total snowpack. Expect to
see 9-10 inches at the highway elevation of 1000 ft in T. Pass. The first report of a
2009
snowboard triggered avalanche came in today. A rider lost his board yesterday at
Flattop. No further details. Although outside our advisory area this reminds us that
winter and avalanche season has arrived.
Tuesday,
Nov. 10, 2009 - 4-6 inches at 1000ft, 14-15 inches at tree line, 0-30 inches in the alpine
November 10th
2009
due to wind erosion or deposition.
Monday,
October 12th
2009
Oct. 12, 2009 - Very warm start to October. Snow line back to 4000 ft. Most ridgetop
snow has melted back in the advisory area. Valley temps in the 50's. An ENSO (El Nino
Southern Oscillation ) pattern is forecasted for the 09-10 season. This is subject to
debate but usually means warmer, drier temps for us in general. Although remember
1998-99 (~1000in).
Thursday,
Sept. 24, 2009 - First measurable snowfall at higher elevations. Snow continued
September 24th through Oct. 25. Approx. 3-4 inches with up to a foot in the Upper Glacier Creek
2009
drainages. Snow line approx. 2000 ft.
The information in this advisory is from the U.S. Forest Service, which is solely responsible
for its content. This advisory describes general avalanche conditions and local variations
always occur.
Part B: Sunday December 6, 2009. Before the tour.
You meet in the front of Atwood at 8 am, it is cloudy and temperatures just below freezing. Your friend
1 shows up at the car with friend 3, ___________________ . On Saturday friend 3 had participated at an
avalanche awareness clinic and your friend 1 had taught them how to use avalanche beacon, probe and
shovel over the weekend. S/he has all the necessary equipment for the day, has never skied in the
backcountry but is skilled downhill skier. S/he is more than eager to go. (5p.)
1. Will friend 3 join you or not? Give the rationale for either decision.
I will let them join us. I understand that he has been through the course so he should respect
avalanche terrain and know it is important to manage it. I trust my friend has shown them how
to use the rescue equipment with a lot of knowledge. I trust my friends judgement, since he too
is a trained avalanche rescuer and backcountry skier like myself.
I will not let this new friend of his go. I don’t know the guy at all. Its not that I automatically
assume friend 3 doesn’t know what they are doing, I am not comfortable skiing with them. Just
because he has the equipment and shown once doesn’t mean he has experience using it. He has
no practice. I would tell him to practice before going into the backcountry.
2. What are the most important safe travelling and group management techniques you would
need to share with friend 3 before you start the tour if s/he is joining the group? Give at least six
techniques.
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We travel downhill one at a time, stopping at safe zones
keep a good distance from each other during up and down hill travel
Have the necessary gear
Know how to use the gear in his pack
Watch for terrain traps
Look for shooting cracks and listen for Whoomphing
Stay out of run out zones when possible
Keep everybody in a somewhat comfortable zone
Communicate with each other effectively.
Always have an escape route.
Know and accept your consequences fully
3. You are conducting a beacon check at the trailhead, when friend 2 notes that they left their
shovel at home. What do you do?
We pack up and go home. What if we are buried and friend 2 is the only one left to find us. He
may find us but not be able to dig us out of avalanche debris. Even after traveling so far to get
there, we will not go out unless we find him a shovel. And I will not just go with friend 3,
because I do not know him/ or her well enough at all.
Part C. Travel observations (10p.)
1. You are concerned that the recent winds may have created unstable wind slabs in some areas.
a. What surface clues could you observe that would indicate that slabs have formed?
Cornicing, wind scouring, pillowing, no snow on the trees, no surface hoar
b. Since the winds have been generally from the E-SE, label on the map the areas along
your route, where you might find these clues.
I have labeled them, there has been winds throughout the week so we should seen
scouring and other wind effects most of the day.
c. Are you expecting more localized wind affects in your route area (not just E-SE winds)?
Please discuss and mark in the map what you might observe.
It appears that there could be a good deal of wind scouring along the slope that we will
be skiing. The prevailing winds look like they will slip along the north eastern facing
slope of my route.
2. What specific weather changes would make you abort the skiing plan (give three examples)?
Over 1 cm of snow falling an hour, obscure cloud cover, or Rapid warming temperatures
3. Explain five ways to make observations about the stability of the snowpack while traveling
without taking your shovel out of your pack.
Sticking your ski pole into the snowpack, ski/ boot test, look for recent avalanches, sounds of
whoomphing, seeing shooting cracks, Hand Shear test, and sometimes a cornice test.
Part D. Rescue scenario (10p.)
You have traveled on the Sunburst uptrack to elevation ~2000ft, where the Taylor Creek valley starts to
open up and you are looking at Sunburst to your N/NW. In the distance you see a party of three skinning
up on the lower west face of Sunburst . Suddenly you hear them yelling “Avalanche!” and see pile of
debris coming down towards you. The debris stops 500ft from your party. Explain what will you do.
NOTE: The location of this avalanche path is marked on the map with black boundary.
Part E. Making decisions (14p.).
One of your buddies is keen to ski Magnum instead of Sunburst after seeing what happened to the other
party.
1. A. What information would you need to decide that this was a reasonable thing to do?
The aspect we will be skiing on, the route we’ll take to get there, the estimated time needed for
the route.
B. What kind of decision making process would you use to come up with a good plan?
I think we could talk about the options and limitations. First we should assess what time it is. Is
there enough time for the trip? Then we’ll talk about if it is worth it to go or not, and how we
will get there. I want it to be a unanimous decision before we decide to do anything. Everybody
in the group must agree it is safe and a good plan.
2. Describe your secondary trip plan with an ascent and a descent route that minimizes your
exposure to avalanche hazard. Include in the map specific locations where you would evaluate
the snowpack conditions.
My alternative route is safer because we are exposed to less avalanche hazard by simply not
traveling as far. We will still get to tour and ski down some slopes but not any of the bigger
ones. When we ascend we will go straight up the ridgeline toward Sunburst Peak. We won’t be
as close to the terrain trap that I noted and the wind loading and slabs won’t play as big of a role
in our day. It is all and all a safer route because it is in flatter terrain, near the trees, and closer
to the road. Plus, right as we are nearing the highest elevation point we will travel too we can
dig a pit to determine the snow pack quality. It is a pretty safe route in my opinion, and really
conservative.
3. So, you dig a pit and do your tests. To find out what your pit looks like, retrieve a snow pit
profile from www.snowpilot.org >View pits > AK > Sunburst Dec 4. (I know, it says it is from
Sunburst, but pretend it is from your pit from Magnum).
a. Where is/are your weak layer/s?
As we already know, the weak layer I at the bottom of the snow pack, but there is also a
wind slab 10 cm from the surface.
b. Does this weak layer have lemons? Explain.
Yes it does have lemons. The weak layer at the bottom of the snow pack has persistant
grain types such as facets and depth hoar. It has a harder layer on top of it by two levels.
There is also a sudden change in grain type from the weak layer to the snow above.
c. What additional tests would you like to do before making a ski decision?
An extended column test to see the likely hood of propagation.
d. How will you interpret this information for your decision making?
If the snow goes it will most likely go all the way to the bed surface, and the pit profile
says that a recent avalanche near here went all the way down already. Though a skier
triggering it is unlikely because the weak layer is so far down in the snowpack. The weak
layer does have two or three lemons but it is still moderately safe. The data was also on
a well representative slope of something I would ski, which is 38 degrees.
4. How might you manage the group on the way down?
As I said before, we need to go one at a time. Even on the smaller runs of downhill terrain I
would like to stop into the safe zones when possible. I am not as experienced as some and I
know it but I can travel safely by being conservative. Also I want to have somebody in charge of
the group picking those safe zones and leading the other to them. I want to gently and gracefully
ski down the mountain, and not bomb down it putting more stress on the snowpack that what is
unnecessary.
Good job! You are done with your exam!
Last quick questions for extra credit:
1. What was your favorite learning activity and why?
I think for me my favorite learning activity we did was digging my individual snow pit at
Turnagain. I took quite a long time, but I really like getting the smooth faces of it, and collecting
data on my own. It really felt as if it I was finally doing some actual snow science on my own.
Then there is skiing, and it always overshadows any of the science stuff we do. It’s just so much
fun, and now I’m going to leave the snow season for a couple of months. I think the course
allowed me to get better at skiing and I like that as well.
2. How could we have made this course better (besides having more snow)?
I think that the course was great the way it was. I like that I had two instructors and only three
classmates. Seeing different snowpacks at Independence mine, turnagain, and glen alps was a
good part of the course, even though it was also kind of necessary due to the snowpack. I
understand it is snow science and we had little snow but more days of touring, that way when I
go with my friends I can see how it is supposed to go and feel comfortable leading them. Don’t
get me wrong though, I got as much of that I as could and I feel pretty comfortable.
3. Are you interested in practica or senior project ideas in snow science?
I am very interested in these options for future research in snow science. The only problem is
I’m also interested in doing these things with caving and rock climbing as well. I have to make up
my mind but I really like snow science and I could see myself at least doing an internship in a
avalanche safety related field.
4. How long did finishing this exam take for you?
Honestly I think I have been working on this exam for about 3 to 4 hours. I don’t know if I got
distracted a lot or not. I still feel like I want more on my map but if I put much more you might
not be able to read it. I don’t think it was too hard, and I like that it is going to help me to
remember a lot of the things that were introduced to me in this course.