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U.S. Army Corps of Engineers
St. Paul District
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St. Paul, MN 55101

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Corps of Engineers is ‘breaking ice’ with annual measurements at Lake Pepin

Published Feb. 13, 2012

ST. PAUL, MINN. – The U.S. Army Corps of Engineers, St. Paul District, survey crew in Fountain City, Wis., will begin this year's annual Lake Pepin ice measurements Wednesday, Feb. 15.

Lake Pepin is located on the Mississippi River between Red Wing, Minn., and Wabasha, Minn. The Corps takes ice measurements on Lake Pepin each year to predict the navigational outlook on the Upper Mississippi River. It is the location of choice for these measurements, because the lake is the last part of the navigation channel where the ice breaks up due to the slower river current in the lake.
Each year, the surveying crew uses an airboat to travel on the ice, a portable global positioning system to identify the exact location for taking the measurement, and a tape measure to measure the thickness of the ice. In addition to measuring the ice thickness, they also record the general condition of the ice. This data is used by the towing industry to predict whether or not it will be difficult for towboats to break through the ice and determine when it's safe to begin navigation to St. Paul, Minn.

Last year, the first tow to break through Lake Pepin and make it to St. Paul was the Motor Vessel John M. Rivers, a tow operated by Ingram Marine Group, of St. Louis, Mo., on March 31. The average opening date of the navigation season in St. Paul for the last 10 years is March 20. For many of those who live in the Midwest, the first tow of the season is the unofficial start of spring.

This year, due to construction at Lock and Dam 7 until March 15, the Corps does not anticipate any up bound, out-of-town tows in Lake Pepin until after March 15.

Normally, ice measurements are completed weekly until the navigation season begins. The data are posted on the St. Paul District’s website. For figures on past and present Lake Pepin ice measurements, see

The U.S. Army Corps of Engineers, St. Paul District, serves the American public in the areas of environmental enhancement, navigation, flood damage reduction, water and wetlands regulation, recreation sites and disaster response. It contributes around $175 million to the five-state district economy. The 700 employees work at more than 40 sites in five upper-Midwest states. For more information, see


Release no. 12-022