The Mill Pond is essentially a wide spot in the Middle Fork of the Crow River and due to the current the Pond remains relatively open when other ponds and lakes have a relatively thick coat of ice. Still, there is no such thing as "safe ice" and even in below-zero temperatures open areas can appear for a variety of reasons.
Given a number of news stories about people going through the ice this season the Minneapolis Star Tribune newspaper is conducting an on-line poll as to what steps should be taken to keep people off the ice. Your vote is welcome: http://www.startribune.com/10142/story/871507.html