Village Science

Winter Trails


A 1, 8c, 15
B 1, 3
C 3
D 1, 3


Forms of energy
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 doesn’t 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 meat.

Traveling Strategy

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

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.

Wind-Covered Trail

Wind-Covered Trail

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 machine.

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.

High-Centered Trail

High-Centered TrailA 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 April.

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.

Impact downwardWhen 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 doesn’t 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 months.

Once the machine is stuck, put brush under the machine providing surface area to stay above the water. Get momentum again and don’t 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 –30°F.

Dogs don’t 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.

Bad Ice

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.

dog sledding

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 haven’t approached yet.

overturned sledIf 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 isn’t 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 don’t 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 home.

Sunny and Cloudy Days

In winter, when the sun is shining, there are shadows everywhere that indicate any unevenness of the snow’s 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 snow’s 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 snow’s surface. It is safer to travel new country on sunny days.

Spring iceFall 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 don’t hold together. Ice two feet thick can crumble under a man’s weight.



  1. 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?
  2. Ask oldtimers in the village how they used the fact that trails set up overnight in planning their travels.
  3. 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?
  4. 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.
  5. 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?
  6. 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.
  7. 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?
  8. Find out if there are people in your village who fell through the ice and how they survived.
  9. 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 open water?
  10. 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?
  11. 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?
  12. Draw a picture of overflow as you imagine it under the snow on the river.
Student Response

Student Response

  1. Why did people with dog teams break trail one day and haul a load the next day?
  2. Which is harder: breaking trail with an empty sled or hauling a load on a firm trail?
  3. How did oldtimers find a trail that was blown over?
  4. Draw the process that causes a trail to become high centered in March and April.
  5. Why doesn’t overflow freeze under the snow?
  6. What did dog mushers do when traveling on bad ice?
  7. What is the difference between fall and spring ice?


  1. 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?
  2. 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?

Questions or comments?
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