The effects of ice damage on grass has driven many a turf manager to despair. It seems that some years the grass underneath the ice can come through the winter just fine. Other years, the turf can be severely damaged and take most of the spring (and a lot of work) to recover.
The risk of damage is partly due to the amount of freezing and thawing that can occur throughout the winter. The grass and soil become waterlogged when the ice melts, then it refreezes and cells in the leaf tissue and crown rupture.
Another factor seems to be snow covered ice versus clear ice. The sun can influence conditions beneath the ice and contribute to damaging conditions. This can also influence the amount of oxygen underneath the ice, if it's lacking, damage can result.
The ever-changing consensus seems to indicate that after 30 days of ice cover, the grass will be at risk of damage.
As usual, I believe the solution is a matter of personal preference. When I worked at golf courses, it was imperative that we remove the ice from the greens, and we did. We used ice chippers, sledge hammers and snow blowers, and it would take days to get all the ice off a green. I've even spread Milorganite (an organic fertilizer) over the surface so that it's dark color would attract the heat of the sun to speed up melting.
At home, whatever happens to my lawn during the winter can usually wait until spring to be addressed. Turf is very resilient and it's capacity to recover from adverse conditions is tremendous. If damage is severe and grass dies, repair it like a bare patch.