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Friday, January 7, 2005
Mont Tremblant, Québec
Great! You got away for a weekend of fun at the local ski resort. As you gaze up at the chilly white magnificence of the blue square run before you, you can't help but ponder all the natural processes taking place there (if you're anything like me, that is!). Well, let's take a look at a few of them now!
It's Cold!
Well, I hope you knew that already. It is cold on the ski slope, so you need to bundle yourself up accordingly. If you don't, you run the risk of hypothermia and frostbite. Hypothermia means your body temperature has dropped below a safe range, down to about 97 or 96 degrees Fahrenheit usually. Heart rate slows. Vital organs don't function as well. Hypothermia is also more difficult to treat than you may think, as a hypothermic person needs to be treated very carefully to prevent serious heart problems in the warming process. Frostbite happens when you leave part of your skin exposed in extremely cold conditions, freezing the blood vessels in that spot and possibly causing nerve damage. This is usually a burning feeling. In other words, when you go out skiing, take breaks once in a while depending on the temperature. If it is especially windy and far below freezing, don't leave any part of your skin exposed! (I've made that mistake before!) Frostbite is not fun. Hypothermia, while it would take a long time to actually kill you, is also something to avoid at all costs.
The Snow
You'll find different snow conditions on the slope depending on recent weather, temperature fluctuations, or even how much of the snow is artificial or real. Artificial snow keeps a semi-powdery coat on the slopes even when there hasn't been a recent substantial snowfall or if the conditions are very icy. Sometimes the artificial snow is made continuously anyway depending on the ski location you've chosen. The difference? That's what you need to know.
Seven Springs Mountain Resort, Pennsylvania
Natural powdery snow is considered the best kind for skiing. Very cold snow falls from the sky as water molecules in a very tiny, unique crystalline form. As long as each one remains frozen as it is when it lands, it remains powdery, and the skis cut through it like butter. However, even when it is still sufficiently cold, it is hard for them to keep this form after being skied on for very long. They are packed tightly together and melt a little, refreezing into a bigger, harder icy form, hardening the terrain and making maneuvering more difficult. When the fallen snow has thawed and refrozen, ice sheets pop up over the slope, since the water molecules have lost their individual crystals and have all attached to each other in one big frozen solid mass, a danger for the unsuspecting skier fated to lose steering and stopping ability here! Artificial snow is an attempt at natural powdery snow conditions, but they are not the nice flakes natural snow is and is little different from very fine ice chips usually. Therefore, you want to ski after there has been a nice substantial snowfall. It's safer and more fun.
Hydrogen Bonds
What is the structure of the snowflake anyway? What makes them so unique? Snow is made up of hexagonal ice crystals. Rather than being perfectly round, they take on a flatter form, a so-called "facet plane". With so many dangling hydrogen bonds on the outer edges of this plane, the crystals grows rapidly from other water molecules in the air, but on the flatter facet plane sides, called the growth facets, grow very slowly. However, even with this basic shape, snowflakes and crystals still take on individually unique forms. This is because of differences in temperature and humidity. For each flake and crystal, these are rarely exactly the same, yielding different looking ones each time, although theoretically you could find identical ones. Lower humidity yields simpler shapes. High humidity can form needles! The reasons for the different shapes due to temperature is still unknown.
Watch How Fast I Go
The ski slope is an excellent example of basic physics. Gravity. Friction. Acceleration. It's all there. Anyway, let's look at some common skiing moves and how they affect the physical nature of this fun activity, as well as what makes it so much fun in the first place!
Now that you've gotten off the chair lift, glide on over to a nice, safe green circle run. Being on the flat top of the mountain, you need to use your poles to move yourself along, as gravity has a minimal role here. Being a green circle, the trail begins as a slow, steady decline, and now you begin to gain momentum due to gravity, smoothness of terrain, your mass, and the fact you waxed your skis that morning, allowing for much less friction between snow and skis. Oh no! You're going a little faster than you want to now. How do you slow down? Well, the main thing moving you along is gravity, right? How can you reduce the gravity factor here? Turn! This way, turn to one side and you won't be heading down in quite the same speed. Before you go off into the woods or off the side of the trail, turn downwards again, but then turn once more to the other side to keep going slower (and be sure to watch out for other skiers!). Eventually, you'll learn a nice gravity-defying slalom! Finally, the trail gets flatter again, but you must make a sharp turn to head down the direction you want. Once you're going that way, you can see the bottom and the chair lift in front of you, but the hill is steeper now. Push off and speed on down there! Faster and faster you'll go, accelerating, until finally you're to the bottom and the ground has flattened out. You lose speed now that the gravity is no longer such a factor as you turn into the chair lift line. 
Seven Springs Mountain Resort, Pennsylvania
Go down the trail a few more times and then go to the blue square slope. This one begins as a much steeper drop, so begin your gravity defying turns to keep from getting up too much speed. Remember, the faster you are going, the worse the fall or crash.
After much practice, you have decided you are ready for the black diamond. The start-off steepness is a factor just like on the blue square but lasts longer. Also, the diamonds have other obstacles affecting the physics of the slope. Moguls are common. They are man-made mounds of snow right there on the slope and always are in groups. If you are speeding down the slope and you happen to race over one of these, your face will be in the snow before you know it. They are sort of like speed bumps in this sense, but moguls are actually obstacles for advanced skiers to ski between. There are also half-pipes, jumps, and other fun obstacles to play with, all of which toy with the effects of gravity and speed. As any study of projectiles, the faster you are going when you reach the jumping ramp, the farther you will fly. Of course, the faster you are going and the farther you fly, the harder you may land and the more injured you may be from the force of any impending collision.
Where to Ski
Well, for downhill snow skiing, mountains are a good place to go, specifically in the winter time. Also think about your particular skiing desires. The Appalachians around Pennsylvania and New York are quite good with plenty of snow and precipitation. Those near the Great Lakes receive what is known as Lake Effect. This occurs when cold air passes over warm, large bodies of water, and a result of this is bands of heavy snow precipitation, leaving several inches of snowfall per hour. The Laurentians in Québec are even shorter than the Appalachians, but they are full of natural snow and temperatures remain below freezing more often. Being so far north is definitely an advantage. The Rockies, of course, are the place to go. Tall mountains give lots of snow and extremely long runs. Also allows for more varying ski activities. Then there are the Alps. Around the world, there are many great skiing places.
Lac Tremblant
So take regional weather into consideration as well as altitude, latitude, and terrain. What influences the weather patterns? How much precipitation do they get? Is it just a good ski place because of altitude alone or does latitude have a significant effect as well?
McGill Outing Club House
Back to the Lodge
Hope you had fun today. Go inside and keep warm after such a fun day of low friction acceleration and high force impacts. Sit inside and watch the pretty white crystal hexagons drift down from the cloudy sky, replenishing the slopes for another ski day tomorrow. See you again real soon!
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© 2004-2007 Katrina G. Moncure unless otherwise stated. Do not copy anything on this site without my permission. All rights reserved.