The frigid temperatures had an upside in Duluth this week, bringing spectacular waves of sea smoke to the harbor. Sea smoke forms when colder air moves over warmer water, the same principle leads to lake-effect snows.
Temperatures reached as low as -15 degrees in Duluth for Christmas on Monday, making it one of the coldest Christmas days on record. On Tuesday, temperatures reached as low as -22 degrees.
Photojournalist Derek Montgomery bundled up to catch the views at sunrise.