I've been on ice covered with rocks and sand. Not 'in' the ice.
It's very deceptive as it appears to be a rock, gravel and sand field. When stepped upon it is very, very slick and dangerous. Underneath there can be ice to quite a depth. Unless someone is standing there warning one it's easy to make a mistake - there is no hint of ice.
In the Andes I saw a cross-section of 5 feet of rock over solid ice down as far as one could see, about 15 feet. I cannot understand how that happened. Quite often there is nothing nearby to tell how the rocks got there.
Arf