The snow would actually cause the plane to decelerate quicker because of the insanely higher amount of friction... even if it's a solid sheet of ice underneath. The inverse of this (taking off) is why some planes expecting to take off from a snowed-in runway (or just fields) will use skis... their motors can't get them up to speed because of all the added friction.
The real problem is what u/bitches_love_brie suggested... the pilot couldn't see the obstacle because of a lack of contrast, so landed a little early. Probably also combined with not being able to tell exactly where the ground is (for same reasons).
Some backcountry pilots will straight up carry a board with them (think 2x4), do a low pass where they toss out the board, do a go around, then the board will help them get their bearings (being a known size) for WHERE the ground actually is.
Source: am a pilot and hang out with others who have way more hours than me.