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.
Changes in the pressure create the flow of the air to move up and down in the ear and thus create popping sound.
Explanation:
The ear-popping is caused by the phenomenon of the opening of the Eustachian tube when one swallows and it might be automatically when you blow our nose or are setting in an airplane and this sound is created when the air enters the middle ear through the tube.
