Marquette, Michigan – Extremely dangerous marine conditions are expected to develop across much of Lake Superior Friday, prompting mariners to remain in port as gale-force winds and rapid ice accumulation threaten vessel stability throughout the day and into early Saturday.
According to the National Weather Service in Marquette, Gale Warnings and Heavy Freezing Spray Warnings remain in effect beginning early Friday morning across central, western, and eastern Lake Superior. North winds will increase to 20 to 35 knots, with gusts as high as 45 knots in open waters, especially east of Marquette toward Grand Marais and Whitefish Point. Wave heights are expected to range from 5 to 8 feet in western sections, increasing to 11 to 17 feet in eastern Lake Superior.
Heavy freezing spray rates of two centimeters per hour or greater are expected, creating rapid ice accretion on decks, railings, and superstructures. This level of icing can disable mechanical systems and significantly raise the risk of capsizing, even for large commercial vessels. Areas from Saxon Harbor to the Keweenaw Peninsula, Isle Royale, Munising, and the Huron Islands are all included.
Mariners are strongly urged to delay departures, seek safe harbor, and secure vessels ahead of deteriorating conditions. The most severe hazards will persist through Friday evening, with freezing spray continuing into early Saturday in many zones. Additional marine warnings may be issued as conditions evolve.
