Great Lakes regulated navigation areas.
Within Lake Michigan, the following is a regulated navigation area. The waters of Lake Michigan known as Gray's Reef Passage Regulations. The COTP, Sault Ste. Marie, will close and open these regulated navigation areas as ice conditions dictate. Under normal seasonal conditions, only one closing each winter and one opening each spring are anticipated.  Prior to the closing or opening of the regulated navigation areas, the COTP will give interested parties, including both shipping interests and island residents, not less than 72 hours notice of the action. No vessel may navigate in a regulated navigation area which has been closed by the COTP.  Under emergency conditions, the COTP may authorize specific vessels to navigate in a closed regulated navigation area.