The most common and most likely answer to this crossword clue is the 9 letter word CREVASSES
I've seen this crossword clue in Independent
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More clues leading to the result CREVASSES
Buddy explains!
The straight part
We know that "Cracks" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cracks = crevasses.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CREVASSES mean?
CREVASSES noun- A crack or fissure in a glacier or snowfield; a chasm.
- A breach in a canal or river bank.
- A discontinuity or “gap” between the accounted variables and an observed outcome.