Factors influencing the choice of ointment. Thermal insulating properties of snow and why sleeping in snow is cold Temperature of snow at the base and on the surface

Snow forms when low temperatures ah and moisture in the form of tiny ice crystals in the atmosphere.

When these tiny crystals collide, they connect with each other in the clouds and turn into snowflakes. If enough crystals are connected to each other, they become heavy and fall to the ground.

At what temperature does snow form?

Precipitation falls in the form of snow when the air temperature is below 2 °C. There is a myth that the temperature must be below zero for snow to form. In fact, the heaviest snowflakes fall already at temperatures between 0 and 2°C. Fallen snow begins to melt when the temperature rises above 0 °C, but as soon as the melting process occurs, the air temperature in the area where the snow is located begins to decrease.

If the temperature is above 2 °C, then snowflakes begin to melt and fall, most likely, in the form of wet snow rather than regular snow. And if the temperature does not drop, then instead of snow it will rain.

Wet snow vs dry snow

The sizes and shapes of snowflakes depend on the number of crystals grouped together, and this in turn is determined by the air temperature. Snowflakes falling through dry, cold air will be small, crumbly snow deposits that do not stick to each other. This dry snow is ideal for winter sports, but in windy conditions it is more likely to slip.

When the temperature is slightly above 0 °C, snowflakes begin to melt at the edges, thus sticking to each other and turning into large, heavy ones. snow flakes. This creates wet snow, which easily sticks and from which you can make a snowman.

Snowflakes

Snowflakes are several ice crystals that may have various shapes and species including prisms, hexagonal plates and stars. Each snowflake is unique, but because they fit together in a hexagonal structure, they always have six sides.

At low temperatures, small snowflakes with a simple structure are formed. At higher temperatures, each snowflake can be formed from a huge number of crystals (star-shaped snowflakes) and they can be several centimeters in diameter.

At ski lubrication for professionals Many factors are taken into account:

• Temperature, humidity, snow classification.
• The nature of snow friction.
• Wind and more.

Lubricating skis for gliding: paraffins, powders, accelerators.

Temperature, humidity, classification and snow friction

Temperature indicated on the package of paraffin or ointment is the air temperature. It is advisable to take air temperature measurements at several points along the route. It is also necessary to know the temperature of the snow, but here it is important to remember that the snow temperature does not exceed 0 degrees. In this case, you should focus on the air temperature.

Humidity- the use of many ointments or paraffins directly depends on the level of humidity. Competitions may take place in an area with average humidity up to 50%, with humidity 50-80%, or humid climate from 80 to 100%.

Snow classification
When choosing paraffins and ointments, the type of snow crystals is important. Falling or freshly fallen snow is the most critical situation for lubricating skis. Sharp crystals of freshly fallen snow require paraffin or ointment, which prevents the crystals from entering the lubricant layer. At positive air temperatures, when the saturation of snow with water increases all the time, water-repellent ointments are required. In addition, depending on the grain size of the snow, it is necessary to roll larger or smaller grooves onto the sliding surface:

• Fine-grained snow and sharp crystals require rolling narrow, smaller grooves.
• Older, stale snow at average winter temperatures requires rolling medium grooves.
• Water and large, round snow crystals require rolling large grooves.
• Fresh snow is falling and freshly fallen snow characterized by relatively sharp crystals and requiring a hard putty.
• Frozen granular snow, if wet snow freezes, then we get snow characterized by coarse grain with particles of frozen water; the use of klister is required as soil.

Snow friction when lubricating racing skis is divided into:

• Wet friction of snow - At positive temperatures.
• Intermediate friction - Temperatures from approximately 0°C to -12°C. Friction with a sliding fraction depending on temperature.
• Dry friction - Temperatures from approximately -12°C and below. As the temperature decreases, the thickness of the lubricating water films decreases until their effect on snow friction becomes completely unnoticeable.

Wind

Wind can easily change the surface of the snow. Skis, as a rule, glide poorly on snow blown by the wind. This happens because the snow particles are broken into smaller ones, which rub against each other, resulting in the snow becoming denser. Higher surface density increases the contact area between the ski and the snow, which leads to higher friction.

• The atmosphere and snow conditions are constantly changing. Snow under the influence atmospheric phenomena can heat up or cool down.
• Over-humidification causes condensation on the surface of the snow, releasing latent heat and necessitating the use of a warmer wax than would be necessary based on temperature alone.
• In dry weather, the reverse process occurs, removing heat from the snow layer, requiring the use of harder ointments than dictated by air temperature.

• Required melting temperature of paraffin: at 120 degrees, to achieve it the iron must be heated to 150 degrees
• Paraffin is heated by pressing several paraffin sticks folded together onto the hot surface of the iron.
• After placing the molten part of the paraffin on the sliding surface, it is heated and allowed to cool.
• After this, remove excess paraffin with a sharp plastic scraper and finish the job with appropriate brushes

Paraffins for low temperatures should be applied in the same way, but excess paraffin must be removed immediately, without allowing the ski to cool. Otherwise, excess paraffin will chip off when removed. After the ski has cooled, the remaining paraffin is removed with a sharp plastic scraper and the surface is treated with hard nylon brushes.

Powder application

• Before applying the powder, the surface of the ski must be waxed according to snow and weather conditions.
• Sprinkle a thin layer of powder onto the sliding surface and heat with an iron (one time).
• Iron temperature approximately 150°C - ointment heating temperature from 110°C to 120°
• Then let the surface cool and then brush it with a brush made of horsehair and clean with a soft nylon polishing brush.

Dry powder method- by rubbing it into the surface of the ski with a clean synthetic cork. This is followed by finishing the surface with a horsehair brush and a soft blue nylon polishing brush.

TEMPERATURE The temperatures indicated on the packaging of Swix ointments are air temperatures. The first starting point when choosing an ointment is measuring the air temperature in the shade. This must be done at several points along the route, especially taking into account which point is the most critical, such as a flat section. It is also useful to know the temperature of the snow surface. But remember that, having reached the freezing point (O°C), the temperature of the snow will not rise further, no matter how much the air temperature rises further. In this case, it is better to use air temperature and pay more attention to determining the water content in the snow.

HUMIDITY

Humidity is important, but more as a local climate trend rather than as a need to accurately measure its percentage each time. It is only important to know whether the competition is taking place in a dry climate zone, with an average humidity of up to 50%; normal climate with humidity 50-80% or humid climate from 80% to 100%. In addition to this, of course, it is necessary to note the situation when precipitation occurs.

SNOW GRAINNESS

When choosing an ointment, the type of snow crystal and the resulting snow surface are also important. Falling or very fresh snow that has just fallen is the most critical situation for lubrication. Sharp crystals require an ointment that does not allow snow crystals to penetrate, and at higher temperatures it must also have water-repellent properties. It is in this special, critical lubrication situation that Sera F excels.
At positive air temperatures, the snow temperature remains equal to 0°C.
The amount of water surrounding the ice crystals increases until the snow becomes saturated with water. In this case, highly water-repellent ointments and rolling large grooves onto the sliding surface are required.

• Fine-grained snow and sharp crystals require rolling narrow, smaller grooves.
• Older, stale snow at average winter temperatures requires rolling medium grooves.
• Water and large, round snow crystals require rolling large grooves.

OTHER FACTORS

The snow changes from fresh new snow to ice. This means that the properties of snow also change between extreme points. To satisfy both extreme conditions and all intermediate conditions, a sufficient number of ointments and the corresponding profiling (structure) of the sliding surface are necessary.
The atmosphere and snow conditions are constantly changing. Snow can heat up or cool under the influence of atmospheric phenomena.
The rate of change depends on air temperature and humidity. Thus, overhumidification of the air causes condensation on the surface of the snow, as a result of which latent heat is released, and it becomes necessary to use warmer ointments than would be necessary based on temperature alone. On the other hand, during dry weather, snow sublimation occurs - a process that removes heat from the snow layer. This requires the use of harder ointments than dictated by air temperature.
Wind can easily change the appearance of the snow surface. Skis, as a rule, glide poorly on snow blown by the wind. This happens because the snow particles are broken into smaller ones, which rub against each other, resulting in the snow becoming denser. Higher surface density increases the contact area between the ski and the snow, which leads to higher friction.
Albedo, or reflectivity, is an important but often overlooked factor. Snow surface albedo determines the amount of energy solar radiation absorbed by the snow surface. Reflectivity depends on the size and density of snow grains, the angle of elevation of the sun, the altitude of the area above sea level and the degree of contamination of the snow surface. Dry, clean snow at low standing sun may have an albedo of about 95%; this means that almost all incident radiation is reflected. Very dirty, porous, wet snow may have an albedo between 30% and 40%; in this case, approximately 2/3 of the incident radiation is absorbed by the snow.
The incident radiation is shortwave ( visible light). The Earth, which to a fairly good approximation is a heated black body, emits long-wave thermal radiation (mostly far infrared). In clear weather, due to this radiation, the soil can noticeably cool. IN cloudy weather Warm radiation is reflected by clouds, leading to warming.
All this means that, in addition to temperature and humidity, you also need to consider whether the surface of the snow is cooling or heating as a result of processes associated with radiation, since the course of these processes may not depend on temperature.
In general, you need to feel what is happening in terms average temperature air, snow temperature, humidity and water content in the snow. . Also identify weather trends throughout the day, such as how quickly it gets warmer early morning until race time around noon. When training, pay attention to whether there is a tendency for the temperature to rise sharply during competition hours. This information about weather trends should be taken into account when choosing an ointment.

When the first snow falls on the ground, and airy fluffs cover everything around with a soft snow-white carpet, it seems as if there is nothing weightless than a tiny and small snowflake: it weighs about a milligram and rarely reaches three.

It’s amazing how, in a matter of hours, snow-white precipitation manages to cover vast expanses of land with a thick fluffy blanket, which turns out to be so heavy that it directly affects the speed of rotation of our planet. For example, snow in the summer, in August, covers only 8.7% of the entire surface of the Earth, while its weight is 7.4 billion tons, and by the end of winter, before the beginning of spring, its mass doubles.

Snow is a type atmospheric precipitation, which consist of small ice crystals falling onto the surface of our planet from nimbostratus clouds in winter time year, creating a snow cover that constantly or with minor interruptions covers the earth's surface until the arrival of spring.

In the region where snow has fallen, sub-zero temperatures are established, keeping precipitation in crystalline form.

When temperatures rise above zero, the snow melts, and if this process occurs at the beginning of spring, this symbolizes the end of the cold period. Ice crystals do not fall out everywhere: people living in countries located in equatorial latitudes (Africa, Australia, South America, South-East Asia, New Zealand and some Central Asian countries).

Snowflakes fly to the ground from nimbostratus clouds after water droplets adhere to condensation grains, tiny dust particles, located in the clouds. If the temperature is upper layers atmosphere is from -10°С to -15°С, precipitation falls of a mixed type, since it consists of drops and ice crystals (in this case, it will rain with snow or sleet), and if below -15°С, it will consist only from ice crystals.

When the formed crystals begin to move up and down the cloud, they gradually increase due to the droplets sticking to them (they partially melt and crystallize again). As a result, the ice floes acquire six-pointed plates or stars, the rays of which are either at an angle of 60 or 120 degrees. After this, new crystals begin to stick to the tops of the rays, to which drops also freeze, as a result of which snowflakes take on a wide variety of shapes.

Crystals usually white, which they acquire thanks to the air trapped inside them: after snow has fallen, Sun rays, bouncing off the air and the boundary surfaces of the snowflakes, they scatter and give it a snow-white appearance. It is worth noting that any snowflake is 95% air, and therefore is characterized by low density and slow falling speed (about 0.9 km/h).

The following types of ice precipitation exist:

• Crystals - their diameter is several millimeters, they are mainly hexagonal in shape;
• Snowflakes - each contains about a hundred crystals fastened together, which in case of wet precipitation can reach large sizes(up to 10 cm in diameter);
• Frost – extremely cold and small droplets (such as fog);
• Hail - this snow usually falls in the summer in the form of large, hard pieces of ice and is formed when large drops stick to the crystal.

Types of snow cover

After the snow has fallen for the first time, it comes climate winter(a period when temperatures are below zero degrees Celsius for five days). If the temperature in the lower layers of the atmosphere, while the snowflakes are falling, turns out to be very low and it will blow strong wind, the crystals will collide with each other, break, crumble and fall to the ground in the form of debris.

But if ice crystals begin to fly to the ground at above-zero temperatures, wet snow will fall. It is worth noting that if rain and snow fall from a cloud at subzero temperatures, the precipitation will freeze to the road and form ice.

The snow on the ground is constantly changing. Exactly how the snow cover will look depends largely on winds (they make it uneven), rains (they compact it), thaws, seas (in the east of Russia there is much more ice precipitation than in Western Europe: due to influence Atlantic Ocean Precipitation here falls in the form of rain).

There are the following main types snow cover:

• Fluffy snow - after snow has fallen, it remains an untouched fluffy cover for some time. This snow in winter is notable for the fact that it is a soft cushion, and therefore a fall usually occurs without injury: the loose snow softens the blows. It is very difficult to move along it, it may well hide stones, ice, tree branches underneath, and due to the fact that it is impossible to accurately determine the depth of the snow cover, you can suddenly find yourself knee-deep in a snowdrift and even get stuck.
• Hard - than more people trample the snow cover, the harder it becomes. If it is not rolled out, then moving around is much easier.
• Nast - crust hard ice which covers fluffy snow. It is formed by the sun and the wind: the snow melts first under the sun's rays, after which the cold air freezes it again. The crust can be soft, medium and hard: the soft crust will fall through, you can walk on the hard crust, and if it turns out to be medium, the pedestrian will either slide or fall through. In the mountains, weak adhesion between crust and snow can cause an avalanche.
• Ice is frozen wet snow that has melted several times and frozen again. This type of snow cover is the most unpleasant because it is very hard, smooth, slippery, and a fall is fraught with serious consequences that can lead to injury or even fatalities. You need to move along it very carefully and, if possible, avoid it.
• Wet snow - after air temperatures rise above zero, ice crystals begin to melt and, filling with water, turn into sleet. As a result, snowflakes begin to stick together and form lumps of ice. Walking on it is quite dangerous: you can get your feet wet, which is fraught with a wide variety of diseases, and if you slip, you can end up in cold water and get wet.

Time of snowfall

Since in Lately The climate of our planet is changing enormously, given the unpredictability of the weather, it is quite difficult to predict when the first snow will fall. For example, in Yakutia, Chukotka, and the Krasnoyarsk Territory, the first snow can be seen already in early October, and snow melts in some areas only in June.

But in Oymyakon (located south of the Arctic Circle) it is impossible to determine when the first snow will appear. Despite the fact that permanent snow cover here usually appears at the end of September, it can also be seen in August (snow melt in this region occurs in the spring, at the end of May).

As for Europe, the first snow here occurs already at the end of October or at the beginning of November (the very first snow was recorded in the seventies in Moscow: it fell on September 25). It falls mainly at night, when the air temperature drops and gives snowflakes the opportunity to reach the ground.

The first snow does not last long: during the day, when temperatures rise significantly, and disappears within a few hours. But after a permanent winter cover is established, the snow remains for a long time, until spring: the snow finally melts in March or even April.

Concerning southern hemisphere, then the northernmost points where snow has ever fallen are Buenos Aires in South America, the Cape of Good Hope in Africa, and Sydney in Australia. True, it melts quickly and falls infrequently: for example, in July 2007, snow fell in Buenos Aires for the first time in eighty years (the reason is cold air from the Arctic). According to meteorologists, they witnessed a rare event, similar look precipitation can be observed here only once every hundred years.

Melting

Snow usually melts in the spring when changes occur temperature regime: Snow melting occurs at temperatures above zero degrees Celsius. There are often situations when it melts at sub-zero temperatures (under the influence of sunlight: ice crystals evaporate, bypassing the liquid stage) .

If the snow is dirty, it melts faster (which is why it disappears much faster in the city than in the forest): the sun's rays heat the dirt, causing the snow to melt.

Salt also often helps the snow cover disappear; it does not melt the ice, but destroys the crystals, which first cool and then return to temperature environment as salt water, giving the impression that the snowflakes have melted.

When the snow melts in the spring, the density of the snow cover changes very quickly. At first it is 0.35 g/m3, then 0.45 g/cm3, and at the very end it reaches its critical density of 0.6 g/cm3. T Snow melting ends when wet snow reaches a density of 0.99 g/m3 and turns into water. After this, the long-awaited spring comes.

It is no coincidence that most natural avalanches occur during or immediately after snowfalls, since the snow layer is not able to withstand a significant amount of fresh snow on the slope that has fallen in a short period of time. Even more than other factors, weather influences the stability of the snowpack by changing the balance between traction and load forces. Let's look at how precipitation, wind and air temperature affect this balance.

Precipitation (type, quantity, duration, intensity)

The effect of precipitation is to increase the weight of the snow layer, and therefore the load on it. New snowfall or rain, especially heavy rain, can make the snow extremely unstable. An important difference between these two types of precipitation is that fresh snow can increase the strength of the snow mass, providing some degree of cohesion. Rain adds weight without adding strength to the layers. In addition, it weakens the holding forces, destroying the bonds between snow grains and between snow layers. Although wet snow can be extremely unstable, once it freezes it can also be strong and stable. The rain-soaked layers turn into ice crusts, which help to solder the structure of the snow layer. However, these crusts form randomly within the strata and on the surface. Especially smooth ones form an excellent bed for a future avalanche.

The extent to which fresh snow is related to old snow is as important as the type and amount of precipitation that falls. In general, rough, irregular and pitted surfaces provide stronger traction by acting as natural “anchors” than smooth surfaces. For example, a thin layer of unconsolidated snow overlying a very smooth ice lens can form a very large avalanche zone after new snow falls.

There is no clear answer to the question of how much snow is sufficient to cause instability and subsequent avalanches. During some snowfalls, more than 60 cm of fresh snow can fall and practically no avalanches occur; during others, 10 cm can fall and a high avalanche danger occurs. This depends in part on the binding properties of freshly fallen snow and on the strength of the layers within the snow column. However, as a rule, avalanches occur under the influence of additional load from a large amount of snow that has fallen or been blown by the wind.

The response of the snow layer to load depends to a large extent on the weight of the fallen snow and the rate of its accumulation. During intense snowfall (from 2 cm/hour), the snow layer instantly reacts to the critical mass of freshly fallen snow, as it is not able to withstand this load. Often, with such intensity of snow accumulation, 90% of avalanches occur during a snowfall or within 24 hours after it. But the avalanche dangerous period persists for another 2-3 days, depending on the processes occurring inside the snow layer. It's like stretching a rubber band until it breaks. The slowly growing layer of snow gradually responds to changes by flowing, bending and deforming plastically, although collapse can still occur, especially if there are weak layers in the underlying horizons. The faster the snow accumulates, the faster the snow layer will react to the additional weight. Under the same conditions, 50 cm of new snow falling in 10 hours is more likely to create a critical situation than 50 cm of snow falling within 3 days. Add the factor of wind, temperature changes and the task becomes much more difficult.

Temperature (snow and air temperature, direct and reflected solar radiation, gradients)

Changes in snow temperature can significantly affect its stability. These changes, in turn, are associated mainly with changes in air temperature, direct solar radiation (directly received from the sun) and reflected radiation (from earth's surface in atmosphere). Air temperature is transferred to the snow layer by turbulent heat exchange - conduction (from grain to grain) and by convection (from free air flow). As a result of this process, the snow surface can be significantly warmed or cooled.

The intensity of solar radiation falling on the earth's surface depends on latitude, time of day and season, slope exposure and cloud cover. Although only a small amount of thermal energy is absorbed by the snow surface, significant heating is possible. Snow also radiates heat very effectively and, in clear, frosty weather, can cool greatly to temperatures much lower than the air temperature. This radiation from the surface can be counteracted by counter radiation from a warm layer of clouds in cloudy weather.

The significance of such processes is that snow temperature affects the rate of changes within the snow column, which characterize the stability of the snow cover on the slope.

The warmer the snow layer, the faster changes occur within it. Warm snow (warmer than 4°C) usually settles quickly, becoming denser and stronger. As it compacts, it becomes more resistant to further subsidence. In cold snow layers, unstable snow conditions persist longer because the processes of shrinkage and compaction are slowed down. All other things being equal, the colder the snow layer, the slower the shrinkage process.

Another temperature effect is that the snow layer can weaken over time if there is a significant difference in the temperature of individual layers. For example, between isolated warm snow at depth and colder layers near the surface. Temperature differences under certain conditions contribute to the formation of weak layers caused by temperature gradients, especially in loose snow. Well-defined snow crystals formed as a result of gradient metamorphism (under the influence of temperature changes) are called deep frost (deep frost) or sugar snow. Such a layer at any stage of formation poses a serious threat to the stability of the snow layer on the slope.

Changes in air temperature during snowfall also have great importance, as it affects the connectivity of layers. Snowfalls that start out "cold" and then gradually "warm up" are more likely to cause an avalanche than those that warm snow lies on a warm surface. The fluffy, cold snow that falls at the beginning of a snowfall often bonds poorly to the old snow surface and is not strong enough to support the denser, wet snow that falls on top of it.

The impact of solar radiation can be twofold. Moderate warming of the snow layer promotes strength and stability through shrinkage. However, intense sudden warming, which occurs mainly in the spring, makes the top layers of snow wet and heavy and weakens the bond between snow grains. An avalanche may occur on a slope that was stable in the morning.

Direct sunlight is not the only danger. Weak layers persist longer on shaded slopes, where the snow thickness is not as compressed as on a sunlit slope, and where the formation of deep frost is often enhanced by cooling (cooling) of the snow surface.

Periods of clear frosty weather contribute to the formation of frost on the surface of the snow. These light, feather-shaped crystals can form thin, very weak layers within the snow column, which are covered by subsequent snowfalls and blizzards.

Such conditions also favor the emergence of a temperature gradient and the formation of deep frost in the lower layers.

In warm and cloudy weather, the snow can warm up, which contributes to its settling and hardening. Although such periods can contribute to greater stability of snow on the slope, avalanches still occur quite often during warming periods, especially when the warming is rapid and pronounced. Any rapid, prolonged increase in temperature after a long period cold weather leads to instability and should be noted as "nature's cue".

Wind (direction, speed, duration)

When snow falls without wind on slopes with a steepness of less than 50°, regardless of orientation, a snow cover of approximately the same height is formed, but the thickness of the cover on steeper slopes will be less than on gentle ones.

The direction and speed of wind during snowfall is of great importance because these indicators determine which slopes the snow accumulates or is transported to. As a rule, with a wind speed of 7−10 m/s, most of the snow remains on the windward slope. If the wind blows more than 10 m/s, then the snow is transferred to the leeward slope, settling immediately behind the ridge. The stronger the wind, the lower the snow accumulates on the slope. In the ridge parts, on sharp protrusions of the relief, snow cornices are formed. Being a good indicator of the dominant wind directions in a given area. The collapse of cornices is often the cause of larger avalanches on a leeward, snow-loaded slope.

Increasing wind causes a general snowstorm, which dramatically changes the conditions for the formation of snow cover depending on the local orographic features of the mountain surface. Significant redistribution of snow in the snow cover occurs during snowstorms, which often occur some time after the snowfall has stopped. The wind lifts previously fallen loose snow into the air and transports it to another place, forming compact, often well-connected layers that serve as suitable material for the formation of snow slabs.

During blizzard snow transfer, a very large heterogeneity of the snow cover can be created due to the redistribution of previously deposited snow, blowing it out on positive relief forms, creating large blows in depressions and the formation of snow cornices. On an uneven ground surface with small relief forms, blowing snow transfer levels out the unevenness and makes them hardly noticeable on the snow cover. Close to obstacles, snow transport causes the formation of snowdrifts of complex shapes. The density of snow cover after a snowstorm increases significantly and can reach 400 kg/m3.

Sideslope snow accumulation occurs when the wind blows across a slope, carrying snow from left to right (or vice versa) on the leeward slope of ridges or ridges dividing the slope.

Note that while the leeward slopes become more unstable due to snow overload, the pressure on the windward slopes decreases as the snow blows away. For this reason, windward slopes are often suitable for routes. But remember that wind changes in the mountains are common. Slopes that are windward today may have been loaded with snow yesterday when they were downwind.

The wind speed required to transport snow depends in part on the type of snow surface. For example, 20 cm of loose, unbound fresh snow under the influence of a wind speed of 10-15 m/s can form an unstable snow cover in a couple of hours. An old slab of wind-compacted snow is relatively stable and rarely comes off, except when exposed to external factors. A good indicator of wind-pressed snow is sastrugi on the surface of the snow.

Height above sea level. Temperature, wind and precipitation vary significantly with altitude. Typical differences are rain at the lower level and snow at the upper level (the boundary between them is the snow line) or differences in precipitation and wind speed. Never assume that conditions at one control site will reflect the situation at another altitude!

Conclusions:

Examples of typical weather conditions, contributing to the instability of the snow cover on the slope

— A large number of snow that fell in a short period of time;

Heavy rain;

Significant wind transfer of snow

A long cold and clear period, followed by intense snowfalls or blizzards. Promotes the emergence of a temperature gradient within the snow column and the formation of deep frost, and subsequent snowfalls contribute to the formation of a critical mass;

Snowfalls are initially “cold”, then “warm”;

Temperature changes:

Rapid warming (above 0 ° C) during the day Leads to a critical increase in avalanche danger!

Gradual (moderate) warming compaction, increased connection between layers reduced danger!

Frosty weather slowdown (conservation) of the existing danger and processes inside the snow layer!

Long periods (more than 24 hours) with temperatures close to or above 0 ° C

Intense solar radiation slopes exposed to the sun the longest, in the afternoon can be dangerous!

To summarize, we can say that the weather is the architect of avalanches and, as such, it draws a plan for changing the stability of the snow cover. By anticipating the impact of weather conditions, and comparing their various variations with the structure of the snow column, you can significantly increase your safety when traveling in avalanche territory.