B 1, 3
D 1, 3
F = MA
| Nowadays people effortlessly travel many miles with snowmachines.
Long ago we had only foot power or dog power. We had to carefully
guard the energy available to travel.
It takes considerable energy to compress snow and make a trail.
Breaking trail then and now are vastly different.
Trails Set Up
When it is cold, a trail will set up overnight. We used to make
trail one day with an empty sled or snowshoes, and return the next
day to haul a load. Overnight the snow crystals bond together, making
a hard surface on the trail that supports the dogs and sled.
Strategy in Hauling Meat or Wood
Years ago, when we shot a moose or caribou, we often removed the
entrails and organs, and left the animal until the next day. Even
at 30° the animal doesnt freeze if the stomach cavity
is banked with snow. We snowshoed a trail home, constantly thinking
of the return trip the next day with dogs. No sharp turns or big
trees in the way! When we returned the next day, the trail we had
snowshoed was fairly hard. We then butchered the moose or caribou
and headed home on the packed trail. This method also has the advantage
of giving the meat a chance to cool slowly, resulting in more tender
Much of the oldtimers traveling strategy was based on the
fact that trails set up overnight. When snow was really deep, they
often made camp early and snowshoed out several miles, returning
after dark. The next morning, the trail was hard and easy traveling
for the distance they had snowshoed.
While snowmachines offer power we never considered possible before,
there are conditions when they cannot pull a load and break trail
at the same time. Often an operator will break trail the night before,
and return the next day with the load.
Breaking trail is difficult for man, dogs, and machines. It takes
considerable energy to compact the snow. With dogs, I would much
rather haul a big load on a hard trail than break trail with an
empty sled. Once the dogs are up to their belly in snow, forward
motion grinds to a halt.
For dogs and machine alike, the most enjoyable trail to drive
on is a hard trail that has just received two inches of fresh powder.
The dogs have good footing, but the bumps are minimized by the cushion
of fresh snow that also provides a very low friction surface. Machines
also enjoy the soft cushion of fresh powder.
A trail seldom blows completely over in the timber, but will often
be obliterated in the open places. Oldtimers walked with snowshoes,
probing with a stick, to find the hardened trail in the open places.
A good snowmachine operator can feel the hidden trail under the
Often trail markers are placed on both sides of open places so
travelers know where to enter the brush or timber.
At night, the shadows of a windblown trail can often be seen in
the headlights of a snow machine or headlamp.
trail that is obliterated in January or February will show up later
as the soft snow around it settles.
- The traveler breaks trail.
- The wind blows more snow into the trail.
- The traveler packs that snow down.
- The wind blows snow into the trail again.
As the snow around the trail settles in March and April, it is
hard to stay on the high trail. The sled or snowmachine tends to
slip to one side or the other.
That is why wise travelers make a wide trail from December through
February, as they know a narrow trail will give them problems later.
This process leaves a trail that is high, wide, and hard to travel
on. Snow on either side of the trail is low and soft.
However, in late spring, when the snow is gone from the tundra,
a well-packed trail will still remain, giving the traveler a highway
of snow surrounded by moss and bare ground. The high trail that
was a problem in March and early April becomes a blessing in late
When a snowmachine runs over a trail, it goes up and down with
the terrain. As it comes down after a bump, the impact, or force
of the machine, compresses the snow. This makes the depression on
the far side of the bump deeper.
the next machine comes down the trail, it goes over the same bump,
but comes down harder because the depression is deeper. This compacts
the snow more, making the depression deeper.
It doesnt take long for the trail to be so rough it is painful
to travel, particularly if there is a loaded sled behind. The impact
on the hitch and tongue of the sled is constant.
There is no way to avoid this phenomena. Since force equals mass
times acceleration, the heavier a machine is and the faster it is
going, the quicker it will ruin the trail. The effect can be minimized
by going slowly but, sooner or later, someone will have to break
a new trail, and the process will start over.
Downhill skiers know quite well how moguls come into
being. Dogsleds and cross country skiers seldom travel fast enough
with enough weight to have this type of problem.
When river or lake ice settles or when creeks overflow, water
seeps on top of the ice but under the insulating blanket of snow.
Once the overflow is exposed to the cold air by a passing sled
or machine, it freezes quickly. The next time the traveler comes
by, there is a rough, hard, icy highway to travel on.
Overflow has always been a problem in the late winter and spring
Once the machine is stuck, put brush under the machine providing
surface area to stay above the water. Get momentum again and dont
stop short of safety.
Ruined backs and frozen feet are always possible during efforts
to get snowmachines out of overflow, which can be a foot deep at
Dogs dont get stuck in overflow the way snowmachines do,
though their feet ice up with snowballs. When they pull the ice
off, they also pull hair, making their feet sore. Dogs with webbed
feet suffer more than others.
When traveling on bad ice with dogs, we often string the dogs
out with a long towline, single file rather than double. This keeps
the combined weight of the team, sled and driver over a larger area.
If the sled falls through, there are several dogs far ahead on solid
ice who can pull the sled out.
Of course, when dogs are spread out like this, it is very difficult
to travel in the timber. Some dog or someone will get slammed into
a tree as the leader is around a bend in the trail others havent
the front of the sled goes under the ice, the traveler is in big
trouble, so it is important to keep the front up when this happens.
The harder the dogs pull, the more difficult it is to get the front
of the sled above the ice.
Swimming across creeks was standard practice in the spring. The
driver gets up on the railing of the sled, keeping the back of the
sled down, the front up, hoping the creek isnt too deep. Some
of the dogs get across the creek and onto solid ground when the
sled is entering the water. If this looks marginal, the driver can
extend the towline with a long dog chain. This assures that some
dogs are on solid ground when the sled hits the water.
Snowmachines dont have the luxury of being able to swim,
although they can skim on water for a ways if they have enough inertia.
Some drivers have overestimated the ability of their machine to
travel on thin ice and water. They get a cold bath and a long walk
Sunny and Cloudy Days
In winter, when the sun is shining, there are shadows everywhere
that indicate any unevenness of the snows surface. The light
is coming from one source in one direction. When the sky is overcast
or foggy, it is very difficult to see uneven features in the terrain.
The snows surface looks flat because light is reflected in
all directions. There are no shadows. This makes travel somewhat
dangerous. One time I almost walked off an eight-foot bluff. Everything
looked flat. On an overcast day, it is hard to see the indentations
on the river that could indicate that the ice has melted away beneath
the snows surface. It is safer to travel new country on sunny
and Spring Ice
Fall time, the ice is healthy. Fairly thin ice can hold considerable
weight. During the spring, when the warmed overflow water has seeped
into the river or lake, the ice has turned to long crystals that
dont hold together. Ice two feet thick can crumble under a
- Break trail with snowshoes in powder snow. Walk back along
the same trail within an hour. Walk the same trail the next day
if it has been cold. What differences do you notice?
- Ask oldtimers in the village how they used the fact that trails
set up overnight in planning their travels.
- Ask old people in the village how they can tell which way a
moose or caribou has gone even after the track is blown over.
How does this relate to the above activities?
- Observe trails as they emerge high centered in
March. Ask oldtimers if this was as big a problem with dog teams
as it is with snowmachines.
- Stand on a packed trail. With your eyes closed and a long stick
in your hand, can you feel the trail and walk for 200 yards? Do
you think you could find a trail that is blown over on a lake
or the river by this method?
- Design a rig that could be pulled behind a snowmachine that
would smooth out the bumps in the snowmachine trail. Think about
hidden stumps and the need to adjust height.
- Ask the experienced snowmachine operators in your village for
stories about overflow. How do they get out when they get stuck?
What months does overflow start in your area?
- Find out if there are people in your village who fell through
the ice and how they survived.
- How do people get snowmachines out that fall through the ice?
Do the machines usually run after they have been underwater for
a while? How do people know where to look for the machine in the
- After breakup, check the ice chunks on the sides of the river.
Break them with a stick. Can you see how different it is from
the fall ice? Do you think two feet of that kind of ice is strong?
- From the oldtimers, ask about five places that usually have
bad ice in your area. How do they tell bad ice right after freeze-up?
During the winter after snow covers the ice? In the spring?
- Draw a picture of overflow as you imagine it under the snow
on the river.
- Why did people with dog teams break trail one day and haul
a load the next day?
- Which is harder: breaking trail with an empty sled or hauling
a load on a firm trail?
- How did oldtimers find a trail that was blown over?
- Draw the process that causes a trail to become high centered
in March and April.
- Why doesnt overflow freeze under the snow?
- What did dog mushers do when traveling on bad ice?
- What is the difference between fall and spring ice?
- Force z mass x acceleration. A snowmachine has 1/3 of its weight
on the front skis. It weighs 357 lbs. Another machine has 1/4
of its weight on the front skis. It weighs 402 lbs. Which machine
impacts the trail harder when going over a bump?
- Fall ice is 12 times stronger than spring ice. If Aaron can
walk on ice 21/2 thick in the fall, how thick must ice be
in the spring to be safe?