Plumes of sea smoke -- also known as steam fog -- enveloped Lake Superior on Monday morning in the Twin Ports as subzero air moved across the relatively warm lake water.

Temperatures in parts of the Northland dropped into the 30s below zero on Monday morning. It wasn't quite as cold near the shore of Lake Superior -- about 10 below zero at sunrise along the shore in Duluth -- but it was cold enough for the steam to form. The thick layer of steam fog remained in place as dawn painted a colorful sky above the lake.

More sea smoke is possible in the days ahead, as subzero morning lows are forecast for much of the week.