Top layer: 8 inches of firm snow
Middle layer: 14.5 inches of "white" ice
Bottom layer: 5 inches of "black" ice
|Required reading for ice-out buffs|
I have been told that while white ice is not as strong as black ice, it takes longer to disintegrate due to its unorganized structure. For a good explanation of the difference, see pages 23-24 of the fascinating book Ice: The Nature, the History, and the Uses of an Astonishing Substance, by Mariana Gosnell. You can view the text online by clicking on that link.
Interpret this as you see fit!