With ice retreating, Mississippi River primed for traffic still stuck downstream

Lake City, Minn. – Bill Chelmowski eased the airboat from Lake Pepin's open waters onto a pockmarked sheet of ice, already certain of what he'd find beneath the surface.

In this crucial stretch of river, the roar of an airboat is the cadence of spring. Each year, the U.S. Army Corps of Engineers measures Pepin's ice thickness to help divine when the first tows can break through and reach St. Paul, opening the navigation season.

http://www.startribune.com/with-ice-retreating-mississippi-river-primed-for-traffic-still-stuck-downstream/507807152/