Ice Volcanoes

While they're not really volcanoes, these ice mounds are formed by similar physics, but instead of heat and pressure, these are formed by crashing waves and freezing temperatures. As Lake Michigan freezes and high winds churn up the water, the waves crash into shore. Slowly the ice begins to build up on the shoreline and as it builds, more an more floating ice is piled on top until a mound is created. Then the process begins again at the foot of the mound, and after time goes by, the mounds begin to form further into the lake. Some of these mounds form in a more of a circular way, where the water and ice chunks are tossed up in the center of an area, and the chunks begin to form a cone as the ice is deposited around a central point.

   

Ice mounds and cones line the beaches for miles, and can often extend hundreds or even thousands of feet into the lake. As the winds calm, ice forms on the outer edge of the cones, then, when the waves kick up again, mounds can form on the outer edges of this ice, extending the ice shelf further and further off shore. This is one of the main reasons these mounds are dangerous to walk on, the holes in the cones can be hidden by drifted snow or thin ice. Also, the ice between the mounds can be very thin as well.