When planning your day on the mountain there are a few different things to take into consideration in conjunction with the weather.
- Snow and snowpack conditions
- Wind chill
- Avalanche Risk
Types of Snow
Many people don’t know that there are actually many different types of snow and snowfall which therefore can heavily effect the conditions on the mountain. The type of snow can be diagnosed by the shape of its flakes, the way it falls and how it collects on the ground. For example a ‘blizzard’ is used to describe heavy snowfall over large areas, a ‘snow squall’ is a heavy snowfall over a small area, while a ‘flurrie’ describes light snowfall.
There are also different types of snow flakes;
Asgraupel – snow which falls in a ball form rather than a flake
Graupel – sleet and snow grains – often formed when freezing fog condenses on a snowflake, forming balls of ice – also known as soft hail.
Columns – snowflake that is shaped like a six sided column.
Dendrites – snowflakes that have 6 points, making it somewhat star shaped. The classic snowflake shape.
Ground blizzard – Occurs when a strong wind drives already fallen snow to create drifts and whiteouts.
Lake-effect snow – Produced when cold winds move across long expanses of warmer lake water, picking up water vapour which freezes and is deposited on the lake’s shores.
Needles– snowflakes that are acicular in shape (their length is much longer than their diameter, like a needle).
Rimed snow- Snowflakes that are partially or completely coated in tiny frozen water droplets called rime. Rime forms on a snowflake when it passes through a super-cooled cloud. One of the 4 classes of snowflakes.
Sleet –some refer to sleet as being , rain mixed with snow; while others refer to sleet as ice pellets formed when snowflakes pass through a layer of warm air, partially or completely thaw, then refreeze upon passing through sufficiently cold air during further descent.
When coupled with the wind the type of snowfall and the conditions on the ground, the snow can evolve into snow slabs after being blown creating huge avalanche risks on steep slopes therefore its strongly advised you have a quick look at the snowfall and the type of snow on the ground before heading off piste.
Snowpack refers to the layers of snow, which form due to different temperatures, wind and type of snowfall throughout the season. Assessing the formation and stability of snowpacks is important in the study and prediction of avalanches and therefore is vital knowledge to those both on and off piste. Knowing the type of snow is key to planning you day out one the mountain. Here is a little guide to the types of snow that can be found.
Artificial snow – Snow can be also manufactured using snow cannons, which actually create tiny granules more like soft hail. In recent years, snow cannons have been produced that create more natural-looking snow, but these machines are prohibitively expensive. These are the huge steel poles with the orange pads around them – great for when there is little snowfall.
Champagne powder – Very smooth and dry snow. The term originates from the ski resorts in the Rocky Mountains, which often have these snow conditions. The Steamboat Ski Resort, in Steamboat Springs, Colorado, holds the trademark for the term Champagne Powder.
Chopped powder –Powder snow that has been cut up by previous skiers.
Corn – Coarse, granular wet snow. Most commonly used by skiers describing good spring snow. Corn is the result of cycles of melting during the day and refreezing at night.
Cornice- An overhanging formation of windblown snow. Important in skiing and alpine climbing because the overhang can be unstable and hard to see.
Crud – this can describe a variety of types of snow conditions. Eg windblown powder with irregularly shaped crust patches and ridges, or heavy tracked snow that has re-frozen to leave a deeply rutted surface strewn with loose blocks, or a deep layer of heavy snow saturated by rain
Crust – A layer of snow on the surface of the snowpack that is stronger than the snow below, which may be powder snow. Depending on their thickness and resulting strength, crusts can be “supportable”, meaning that they will support the weight of a human, “breakable”, meaning that they will not, or “zipper”, meaning that a skier can break and ski through the crust. Crusts often result from partial melting of the snow surface by direct sunlight or warm air followed by re-freezing.
Finger drift –A narrow snow drift (30 cm to 1 metre in width) crossing a roadway. Several finger drifts in succession resemble the fingers of a hand.
Firn – Snow which has been lying for at least a year but which has not yet consolidated into glacier ice.
Ice – Densely packed snow that doesn’t contain air bubbles. Depending on the snow accumulation rate, the air temperature, and the weight of the snow in the upper layers, it can take snow a few hours or a few decades to form into ice. This can be lethal on the slopes – especially if you have no edges!
Packed powder- The most common snow cover on ski slopes, consisting of powder snow that has lain on the ground long enough to become compressed by ski traffic, but is still somewhat soft. This is perfect for the beginner skier or the racer. Often helped out and groomed by the piste bashers, there is no better feeling than carving up the freshly packed snow.
Packing snow – Snow that is at or near the melting point, so that it can easily be packed into snowballs, snowmen and igloos! Perfect for throwing at your brother!
Penitentes – Tall blades of snow found at high altitudes.
Powder – Freshly fallen, uncompacted snow. The density and moisture content of powder snow can vary widely; snowfall in coastal regions and areas with higher humidity is usually heavier than a similar depth of snowfall in an arid or continental region. Light, dry (low moisture content, typically 4–7% water content) powder snow is prized by skiers and snowboarders. There is no better feeling than smashing through the powder on floaty fat skis on a bluebird day!
Slush – Snow which partially melts upon reaching the ground, to the point that it accumulates in puddles of partially frozen water. Although heavy when skiing slush can be super fun on powder skis or a board and super forgivining in the park, giving you no excuse to try that backflip you have been meaning to do all season!
Snirt – Snow covered with dirt, which occurs most often in spring. Probably the most annoying and depressing kind of snow!
Snowdrift – Large piles of snow which occur near walls and curbs, as the wind tends to push the snow up toward the vertical surfaces. These can be super fun to jump into!!
Spring snow – Late in the winter season, the mid-morning sun melts the top of the frozen snow base creating a soft layer, 1–2 cm deep, perfect for long carvey turns. On some slopes, the melt layer poses an extreme avalanche risk in the afternoon and ski patrol will close such runs by late morning.
Wind slab – A layer of relatively stiff, hard snow formed by deposition of wind blown snow on the leeward side of a ridge or other sheltered area. Wind slabs can form over weaker, softer freshly fallen powder snow, creating an avalanche hazard on steep slopes.