That is moving nonstop. The ram and back-up capabilities is 21 feet thick. Also listed in this article.
Summer there. This happened to the Vikings after they settled Greenland. The Little Ice Age hit and their ships couldn’t get to their colonies. There was a brief respite, and when they got there everyone was dead. Of course Hansen proved that didn’t happen with a few tree rings.
Ice breaker basically plow through sea ice. The thick stuff they ride up on and break using the weight of the ship. They have a rounded hull and a sloping prow that allows this, but also makes them notorious for wallowing in heavy seas.