Complex sentence: Although primarily composed of flowing snow, air and at times water, large avalanches have the capability to entrain ice, rocks, trees, and other material on the slope, and are distinct from mudslides, rock slides, and serac collapses on an icefall.
Split into simpler sentences: Although primarily composed of flowing snow, air, and water, large avalanches have the capability to entrain ice, rocks, trees, and other material on the slope. Avalanches are distinct from mudslides, rock slides, and serac collapses on an icefall.