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HOW WELL DO YOU KNOW YOUR SNOW?

By Cotswold Outdoor
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If you are off to the mountains this winter, there is a good chance that you will encounter snow in many of its beautiful and intricate forms, but how well do you really know the white stuff? From fresh flakes to age old glacial ice, having a better understanding of how it will behave can make a huge difference to your day.

So to help you in your mountain adventure and to celebrate the winter, we have picked out a few fun and a few serious examples of snow that will help you move in the mountains and could have you pointing out formations to your friends, like a wise old mountain guide.

THE SNOW LIFECYCLE

From the point it forms in the sky, to melting into the ground, you can think of snow as being on a transitional journey. The speed that it completes this journey is dependent on factors such as the climate and geography; but under the right conditions, snow can undergo a metamorphosis from a pile of soft, fluffy flakes, into a rock-hard glacier. We’ve picked a few key stages and listed them below, so next time you roll up a snowball or carve a line down the mountain, you can appreciate the amazing lifecycle of this frozen playground.

POWDER

Skiier in powder snow

Photograph courtesy of Ross Woodhall

Fresh, virgin powder is irrefutable proof that Mother Nature wants us to have fun in the mountains, and for skiers and snowboarders, this deep, soft and cloud-like structure is absolute bliss to ride. Thanks to its large snowflakes and its loose construction, riding over and through powder can feel somewhere between a liquid, solid and a gas, offering exceptional cushioning, carving and lift.

Less popular when climbing up mountains, powder is very tiring to walk through and does require a bit of skill to ski or board. The trick is to keep the speed up and lean back slightly; keeping an eye out for rocks, tree stumps and other concealed obstacles.

CRUD

Skiier on crud snow

Photograph courtesy of Ross Woodhall

Crud is old powder that has been churned up and has begun the freeze-thaw cycle. This process happens to almost every type of snow and involves layers partially melting, binding together as liquid and then freezing again. Crud has been shifted into lumps and divots of various densities making for a changeable, and at times, a challenging surface to ski and board over.

Over the course of a season the freeze-thaw continues, causing the top layer to become harder and thicker. The snow beneath is also subject to freeze-thaw; changing the individual flakes into icier clumps with more rounded edges. This older snow is often referred to as ‘crust’.

NÉVÉ AND FIRN

Neve and Firn Snowy Mountain

If snow stays on the ground for long enough, the constant freeze-thaw cycle and the weight of additional snowfall compresses it into hard, granular layers. As the flakes partially melt in the sun they slide against and into each other, squeezing out air. At night these freeze again into harder, icier clumps. This type of snow is called névé and has the appearance of large sugar granules, but is firmly bound together and hard to the touch.

If névé remains on the ground for over a year it is referred to as firn and it is this process, multiplied over many seasons that forms the beginnings of a glacier. Roughly translating from the German Swiss to mean ‘before’, firn has undergone an extensive freeze-thaw and is so compact it is essentially ice, with a density of 550 kg/m³-830 kg/m³.

ICE

Blue ice

If powder is mother nature’s way of letting us have fun, ice is her way of reminding us that she is in charge. Rock solid, with very little margin for error, the ice encountered on the slopes is not strictly speaking the same as the ice in your drink. Unlike the naturally formed névé and firn, ice on the piste has been compresses into a single, bullet-hard layer under the repeated compression of skis and boards.

Keeping an eye out for ice, and controlling yourself when in contact with it is an important skill. Like in a car you need to arrest you speed gradually rather than slamming on the breaks. The important thing is not to panic and accept that part of using the slopes is being responsive to the constantly changing snow conditions.

 

PISTE

Piste snow

Photograph courtesy of Ross Woodhall

All of the above are stages of snow that can happen if it’s left relatively unmanaged. However, in an attempt to avoid this and to increase its lifespan, resorts groom the snow, creating an area known as the piste. Roughly translating as ‘track’, the piste is groomed by huge vehicles that drag combs and makes up the vast majority of what will be encountered on a skiing holiday.

By managing the slopes, resorts can stop the snow migrating into large piles (moguls) and reduce the impact of the freeze-thaw cycle. With its smooth, uniform surface, the piste makes for a slick and predictable ride.

FEATURES AND FORMATIONS

Moulded by the elements, snow is able to take on many different and dramatic forms. It has the ability to bind itself into rock-hard layers, and achieve apparently impossible formations, only to break or blow away at a moment’s notice. Some are benign wonders, simply appreciated for their beauty, whereas others are sleeping giants, capable of unleashing unimaginable power and destruction. We have picked a few of our favourites for you to try and spot when out in the mountains.

CORNICE

Snowy cornice formation

Cornices are a dramatic and potentially deadly feature. Caused by wind depositing snow as it comes over an edge, they can grow into huge overhangs that look solid to anyone standing above, yet are dangerously unsound underneath.

They are less likely to be a factor in the relatively safety of the resort, but venture off-piste or even to an exposed ridge for a photograph and you could be closer than you think. When participating in any mountain activity it is important that you take responsibility for your own safety, but generally speaking, resorts clear these away or cordon them off. It’s still worth trying to spot them on neighbouring mountains though, as they can be spectacular features.

SASTRUGI

Sastrugi Snow Shapes

Photograph courtesy of Ross Woodhall

SPINDRIFT

Spindrift snow formation

It may appear that snow is deposited from the sky to the ground, but it is in fact not that simple. Yes it falls from the sky and yes, eventually it settles, but in between it is subject to a significant and enduring force; wind.

Next time you are in the mountains look up and you are likely to see little, cloud-like wisps spiralling across the peaks and down the faces. This is called spindrift and is the visual clue that reveals how snow is moved in the mountains, well after it has stopped falling. Wind is responsible for almost every feature and activity. From tiny snow drifts to huge avalanches, wind is often the root cause.

ROLLERS

Snow roller formation

Like in the cartoons, or when building a snowman, it is possible make large amounts of snow stick together simply by rolling it along the ground. Snow rollers are Swiss roll shaped formations that occur due to this exact process. With distinctive and clearly marked spirals, their soft centre can sometime blow away, leaving a doughnut shape instead. Snow rollers require a very specific set of conditions in order to form and are therefore quite rare. They can appear on snow plains where the speed of the wind can force small clumps to roll and gather snow, or on slopes where a piece of snow may fall from an overhanging branch, and then tumble downhill.

YELLOW SNOW

Pint of beer in snow

An elusive and mysterious formation, nobody really knows how it occurs. Recent studies have observed that it is mainly centralised around urban centres, especially near car parks and laybys, but the occasional patch has been recorded miles from any town, which only adds to the mystery.

We have learnt from the early pioneers in the field of yellowsnow research not to eat it, but to treat it with caution. What is it? Where does it come from? Maybe somethings in nature are simply beyond the comprehension of mankind. Like the Yeti or the did-they-didn’t-they assent of Mallory and Irvine, it is a true mountain mystery.

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Ski Club GB

A special thanks to our friends at Ski Club GB for supplying many of the amazing images. For more information on Ski Club GB and to learn more about our special partnership, you can visit the Ski Club GB page ».