serac

 seh-RACK

 A tower or pinnacle of ice, formed where a glacier fractures into chaotic blocks as it flows over a steep drop — an icefall. Seracs are unstable, beautiful, and lethal. They can be the size of houses, standing at improbable angles, and they collapse without warning. Climbing through a serac field is a calculated gamble with time.
Etymology
 French, from Swiss French sérac, a type of compact, crumbly white cheese. The broken, blocky ice was thought to resemble the cheese. The word is purely Alpine.
Notes
 One of the great etymologies in the project — a tower of ice named after cheese curds.
 climbing  ice/snow French mountains
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