About 50 ice anglers had to be rescued from a northern Minnesota lake on New Year's Day after a pressure ridge they were near split and left them stranded, officials said Tuesday.
The Lake of the Woods County Sheriff’s Office said a call came in around 3 p.m. Monday reporting that about two dozen people were stranded on the north end of a pressure ridge that had cracked open, KSTP-TV reported.
Meanwhile a nearby resort was able to reach the people using a boat and bring them to the south side of the pressure ridge, where snowmobiles and utility terrain vehicles took them safely to shore, the station reported.
About 50 people were rescued and were uninjured. The rescue came about a half hour after a man fell through ice on the lake with his all-terrain vehicle. The man was pulled from the ice without incident and suffered no injuries, police said.
Officials continue to warn Minnesota residents that the ice on nearby lakes may be too vulnerable to hold a lot of weight as the state continues to see some of the warmest winter temperatures on record.
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What is a pressure ridge?
Pressure ridges are cracks in the ice that "form as a result of contracting and expanding ice due to air-temperature fluctuations," according to the Minnesota Department of Natural Resources.
When the temperature drops, the ice contracts, causing cracks. Water then fills and freezes into the gap. When the air warms, there is no more room for the ice to expand, causing "one sheet of ice to slide on top of the other." When one layer begins to go under, the ice becomes too thin and open water appears.
In the cases when both sheets of ice fold, that opening of water becomes a lot larger and a much more dangerous scenario, as it's hard to catch. The gap in ice can remain hidden under a thin layer of ice or snow, the department says.
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Rescues, deaths on Minnesota lakes this winter
This latest rescue from Lake of the Woods pushes the total number of known rescues over 200 since mid-December. There have been two deaths.
Dec. 29 - More than 120 ice fishers were rescued after becoming stranded on a large sheet of ice that had drifted out into Upper Red Lake.
Dec. 28 - A vehicle used to transport ice-fishers crashed through the ice on Lake of the Woods, killing one man.
Dec. 23 - A man was found on Big Toad Lake with his ATV upside-down and having drowned in about 4 to 5 feet of water.
Dec. 22 - Two men fell through the ice on Upper Red Lake after their vehicle and trailer broke through a layer of ice.
Dec. 19 - A small passenger plane landed on Upper Red Lake and broke through the ice and partially sunk into the lake.
Dec. 17 - 35 people were rescued after ice broke away from the shore of Upper Red Lake
Mike Snider and Claire Thornton contributed to this story.
This article originally appeared on USA TODAY: 50 ice anglers rescued from Lake of the Woods, Minnesota