Detroit: A recent cold front has brought an interesting phenomenon to the Great Lakes region of the US: ice volcanoes.
National Weather Service meteorologist Ernie Ostuno was able to capture some amazing photos of the eruptions at Oval Beach at Lake Michigan.
An ice volcano is a cone-shaped mound of ice formed over a terrestrial lake by the eruption of water and slush through an ice shelf.
"Ice volcanoes occur in locations in which waves hit accumulated ice on the shoreline with some force," said Cort Spholten, a meteorologist with the National Weather Service of Grand Rapids.
"We were cold enough to form ice on the shore of Lake Michigan and water had broken the surface of that ice," Spholten said.
"The waves ... were strong enough so the water channels through, it squeezes water upwards and tosses the floating ice up. As it happens, over the course of hours or days, it forms a cone and it resembles a volcano."
The ice balls are back on Lake Michigan! It finally got cold enough. Photo courtesy of Holland State Park Facebook page. pic.twitter.com/Dww78BJ7lB— NWS Grand Rapids (@NWSGrandRapids) February 15, 2020
According to Spholten, there have to be very specific conditions for the ice volcanoes to form.
"It needs to stay cold enough to keep the ice around and waves need to be large enough to force water upwards against the ice shelf," he said.
How long will it last?
"Today, winds from the south-east should diminish the waves. It's unlikely ice volcanoes will be seen today compared to yesterday, but it's not impossible," Spholten said.
However, ice volcanoes can also be dangerous especially when people climb on them. There may be no way to get out of the icy water if someone slips down the side of one of the mounds.
The ice volcanoes formed after another rare phenomenon on Lake Michigan.
On Friday, thousands of ice balls rolled up onto the lake shore. According to experts the weather conditions have to be just right: the temperatures are just below freezing along shallow beaches. Slush collects into round shapes and the waves sculpt ice chunks into orbs.