Snow

Antarctica is the coldest, highest and driest continent in the world. It is largely a desert, with most places receiving less than 250mm of water equivalent each year. Despite low precipitation, snow is often mobile at this time of year (September) due to unsettled weather, very cold temperatures and some very high wind speed events. The interplay of wind speed and snow surface conditions create many patterns in the snow as the battle between snow deposition and erosion takes place.

Surface forms in snow can be similar to those in sand, but an important difference is that snow crystals will sinter and bond with each other, meaning that some erosion derived forms, such as sastrugi, are only found in snow. The rate of bonding is a function of temperature, so in the cold of Antarctica snow can remains mobile longer than more temperate snow climates.

Anondo collecting samples among the drifting snow.

Patterns of wind affected snow. The whole photo is about 30cm (1ft) across.

Striated, wind eroded snow (left side) along with some pit marks on the upper surface 

The sound of snow in Antarctica. The main point of interest in this video is the sound of my boots walking across the very cold, dry and well packed snow – the snow crystals are crushing or grinding against each other. It sounds (and feels) a bit like styrofoam.

Footsteps in time? Pressure caused by footsteps (in the foreground) sintered previously deposited snow, making it harder and more resistant to erosion during the next wind event
Small sastrugi, created by erosion, can be seen in the foreground. Mt Erebus is in the background.

Barchan/Dune like formations. The Gerber multi-tool is about 11cm (4.25″) tall. The wind has blown from left to right, with the darker eroded tail on the left side and the brighter deposition zone on the right side

Snow ripple formation, similar to that seen in a stream bed

This post is inspired by recent work from colleagues in Alaska (Filhol & Sturm, 2015).

Reblogged from penguinchasing.blogspot.com

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