If an asteroid strikes a glacier, does it make a print on the land below? For example, a 10 km wide asteroid on a 2 km thick glacier, or a 2 km wide asteroid on a 2 km thick glacier.
A 10 km asteroid would not only obliterate the section of glacier it hit, but also create a huge crater at the impact site!
The asteroid that created the Vredefort crater in South Africa is estimated to have been 10 to 15 km in diameter. It is also estimated that the initial crater created by the impact, some 2 billion years ago before it was eroded, was 300 km in diameter.
To date, this is the largest recognized asteroid crater on Earth. The crater that was produced by the dinosaur extinction asteroid, in the Yucatan (Chicxulub) was only 180 km in diameter. Interestingly, the asteroid that created that crater was also estimated to be 10 to 15 km in diameter.
The Gosses Bluff Crater, in Australia, is 22 km in diameter and it is estimated to have been created by an asteroid 1 km in diameter. The rim of the crater is still 150 m above the surrounding desert.
Any sizable asteroid will vaporize the section of glacier it hits and create a large crater at the impact site.