JohnJ80

When the ground is frozen hard, the ice mechanically bounds to the pavement and pretty much won't let go until melted from above or the ground thaws beneath it. That happens often when we have super hard freezes like we've had this year (Minnesota). If, for example, it thaws a bit and water collects in a low area on dry pavement then there is a hard freeze that ice will be there until spring. I have a patch of that in my driveway and it's pretty much impossible to chip up, it will get covered with water and it won't float up either. It's not just laying on top, it's bonded. Happens all the time around here.

So, if the ground is hard frozen and there is some event that puts water on top (rain, melting, etc) you will have water pooled on top of the ice. Since the water if pretty close to freezing anyhow and the ground is well below freezing, the ice doesn't float up or melt quickly. In point of fact, it's much more likely to wind up with thicker ice than it is for thinner ice.

J.