Even on a flat glacier, falls are a danger because of the deep trenches called crevasses (sometimes hidden by snow) in the glacial ice.
(falls; are; a danger; because of the deep trenches; L:Even on a flat glacier) (the deep trenches called crevasses; hidden; by snow; L:in the glacial ice; T:sometimes)
falls the deep trenches called crevasses
are hidden
a danger because of the deep trenches L:Even on a flat glacier
by snow L:in the glacial ice T:sometimes