LAKE CITY,Minns — The thickest ice remaining on Lake Pepin is 18 inches, down two inches since the previous Army Corps boring a week ago. At its thickest in mid-February the ice was 23 inches. The Corps does weekly borings to advise the Mississippi River navigation industry when the lake is safe. Shippers look for 12 inches or less for barges to have safe passage to Red Wing and St. Paul. Shipping over the past 10 years has begun as early as mid-March and as late as the first week of April.
