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Weather Temperature, wind and snowfall are what creates the avalanche conditions, Higher temperatures can cause snow to melt, while low temperatures causes the water beneath to turn into ice, both of which creating less friction, thus causing the avalanche to slide. Winds can create cornices and snowfall adds on to the weight. Snowfall Snowfall causes more pressure on the existing layers of snow. This can affect the binding of the the layers. Slabs can break apart and fall as a slab avalanche. The thicker the snowfall, the more dangerous it is. Those thicker than one foot are highly dangerous, while those less than 6 inches have a much lower risk. Temperature Small temperature changes do not affect much. However, long and large temperature changes can cause some layers within a snowpack to melt, weakening the bonds between the layers. Wind direction Wind blows in a particular direction and on one side of the slope. While it blows upwards, it blows with it, the snow on the particular side. When it reaches the other side (over the summit), it leaves the snow on the other side creating a cornice. This causes an imbalance and as the weight increases, it causes the snowpack to become unstable. Snowpack conditions Snow builds up in layers, each due to different weather. Thus, each layer bonds in a different manner with other layers. Between these layers, temperatures can rise and melt the exposed surface layers. When these snow freezes again when the temperature falls, it creates a smoother surface. This cause the next layer of snowfall to have a looser grip, creating instability. Snow textures also affect the bonding. For instance, depth hoar. It is coarse and grainy. This causes it to bond poorly with other layers, hence creating a weak layer. Slope angle A steeper slope would generally have a higher chance of avalanche occurence. However, it also depends on the type of snow. Snow that bonds well might still be able to stay on a steep slope. However, when the slope gets too steep, the snow can still fall as there is a limit to their bonding ability. Terrain Terrians can determine the depth of snow. For instance, gullies can cause snow to accumulate to a very deep height. With more pressure on it, an avalanche would be more likely to occur in this area. Vegetation Heavily forested areas less likely to have avalanches occuring as the roots of the trees help to hold the snowpack together. However, lone trees/bushes/etc. can weaken bonds as they catch debris cause the snow to pile up. Also, if the vegetation is low-lying (e.g. shrubs), it can easily be buried by snow and are thus ineffective in holding the upper layers of the snow. |