The Weather Notebook has this to say about Ice Volcanoes:
Ice volcanoes can form during winter on the Great Lakes. They are not lava-spewing mountains of ice, but water-spouting ice cones.
As winter ice begins to build along the shores of large lakes such as Lake Superior, it is jostled, broken, and shifted by the winds and wave motions on the waters. When winds blow onshore, they can build an ice shelf, a jumble of ice chunks that anchors on the shore but extends some distance back into the water. Amongst the numerous ice blocks comprising a shelf, many open tunnels lead back to the lake waters.
To build a good ice volcano cone, the surface air temperature must be several degrees below freezing and lake waves should be several feet high and breaking onshore. As the waves strike the edge of the ice shelf, pulses of wave energy flow beneath the ice. Upon reaching the open end of a tunnel, the wave forces water to erupt out through the ice. If the hole has been covered with snow, the eruption may spray snow outward like a volcanic gas cloud.
As the ejected water falls back onto the ice, it quickly freezes and begins the formation of an ice cone, a process very similar to the building of a lava cone surrounding a geologic volcanic vent. A study of ice volcanoes on Lake Superior’s southern shore by students from Michigan Tech measured ice cones ranging from three to 25 feet in height.
Like rock volcanoes, ice volcano vents can heal over and become dormant during periods of low wave action. They lie in wait for a strong wave surge to awaken them back to explosive activity.
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