Via the Minnesota Department of Transportation:

A tug boat is continuously breaking ice on the St. Croix River in the St. Croix Crossing bridge construction zone. This allows crews to continue work on the new river crossing during the winter months. Currently, crews are breaking ice out to Pier 12, closest to the Wisconsin shoreline. This activity causes thin, irregular and dangerous ice conditions near the construction site.

The project team is asking individuals participating in winter activities on the river between Stillwater and Bayport to use extreme caution and stay away from the construction area. Crews plan to regularly break ice on the river throughout winter 2014-15. Crews will place signs near the bridge work stating: DANGER THIN ICE BETWEEN STILLWATER AND BAYPORT DUE TO CONSTRUCTION ACTIVITY.

Watch a video of the boat breaking ice: