Jet Stream are narrow bands of strong winds from the upper levels of the atmosphere, and its location depends from year to year.
The winds blow from west to east in jet streams, but the flow often shifts to the north and south. Jet streams follow the boundaries between hot and cold air. They follow the boundaries between hot and cold air, so technically they take the heat with them wherever they travel: from north to south. Warming in the Arctic, i.e., melting sea ice, warming air temperatures and rising sea surface temperatures may also be intensifying the jet streams position which in the winter may cause extreme cold winter seen in places like the Northern United States.<span> </span>
Dune deflation hollows are where wind has removed sand down to a level where a layer of particles too heavy for the wind to move (an armoured surface) stabilises the sand and prevents the surface being lowered further.
A crevasse is a deep, wedge-shaped opening in a moving mass of ice called a glacier. Crevasses usually form in the top 50 meters (160 feet) of a glacier, where the ice is brittle.
a mass of rocks and sediment carried down and deposited by a glacier, typically as ridges at its edges or extremity.
