Passersby spotted this blue ice near the Mackinac Bridge in Michigan between Feb. 19 and 21, 2016. (Courtesy of Kelly Alvesteffer and Rob LaLone)
A couple on vacation made a stunning discovery while sitting in a restaurant overlooking the Mackinac Bridge, which connects the Upper and Lower peninsula of Michigan.
Kelly Alvesteffer, who was traveling with her fiancéRob LaLone,witnessed an eye-popping natural phenomenon that gave the floating ice in the Strait of Mackinac a turqouisetint. They took several snaps on their camera and uploaded their sighting to Facebook, which quickly went viral.
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"We instantly saw it. It was like, 'Look at the blue ice,'" Alvesteffer told
According to , "blue ice" forms when air bubbles are squeezed out of the frost due to changes in density, causing crystals to expand and allowing light to penetrate the ice, giving the stark indigoappearance to the human eye.
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