LAKE CITY, Minn. – The Army Corps of Engineers began its annual Lake Pepin ice measurements to start assessing when navigation can resume on the Upper Mississippi River. Typically the ice is safe enough for tows to break through the third week of March. Last spring the tow Clayton McWhorter was first on March 19.
An airboat and auger. . Army Corps survey technician Bill Chelmowski collects ice measurements on Lake Pepin to inform riverboat captains when it’s safe to break the ice and begin the navigation season.
Why Lake Pepin?
At 22 miles long and as deep as 60 feet, Lake Pepin is the widest naturally occurring part of the Mississippi River. As such, it’s the last barrier of navigation to the head of navigation at St. Paul. Ice measurements are collected at Lake Pepin because the water flow is slower and the ice is usually the thickest on the river. Tow captains don’t like trying to break through more than 12 inches of ice.