DULUTH, MN (KDAL) - The U-S Coast Guard cutter Alder has begun breaking the ice in the Twin Ports harbor area in preparation for the opening of the shipping season later this month.  The Alder is clearing channels from near the ore docks to the Superior entry.  Some ice in the harbor is reported to be up to three feet thick.  The Soo Locks are scheduled to open on March 25th.