DULUTH – The fish were biting, and John and Porter Smith were sheltered from the freezing windchill in their icehouse just off the shore of Lake Superior on Tuesday morning. Then they heard a crack.

The cousins were among 26 anglers stranded on an ice floe that broke away from the shoreline near 21st Avenue East in Duluth. The Duluth Fire Department received a call around 11 a.m. from a resident who saw the smattering of ice huts floating away, and crews rescued the anglers a few at a time by boat.

"Lake Superior is not forgiving," said John Smith, looking at the open water that hours earlier had been covered by solid ice.

No injuries were reported. Duluth Fire Chief Shawn Krizaj said his agency responds to similar calls about once each winter but called Tuesday's incident one of the biggest rescues in recent years. The Coast Guard, the St. Louis County Sheriff's Rescue Squad and the Duluth Police Department provided assistance.

Last week, several agencies rescued 66 people stranded on an ice floe in Lake Michigan, near northeastern Wisconsin.

"The problem with ice fishing anywhere is it's only as safe as it is at a given moment in time," Krizaj said.

While cold temperatures have helped create ice on the big lake's bays in recent days, Lake Superior as a whole is just 10% covered with ice, according to the National Oceanic and Atmospheric Administration, well below average for this time of year. That allows ice along the shore to suddenly drift toward open water depending on weather and water conditions. The ice that has formed on Lake Superior near Duluth is no more than 6 inches thick, according to NOAA data.

Open water to the east is visible from Duluth's shoreline, and winds were blowing from the southwest about 25 mph at Sky Harbor Airport on Park Point at noon Tuesday, according to the National Weather Service.

Many anglers did not realize their ice shelf had separated from the shore until they heard yells and sirens. Devin Stein, 25, was able to leap 3 feet of open water before the channel grew bigger.

"A couple people started sprinting toward the shore," said Jack Norquist, a 22-year-old student at the University of Minnesota Duluth. "It wasn't the scariest thing, but it wasn't fun."

The anglers hung around Tuesday waiting for news of their ice fishing gear, which was still floating up the North Shore. The ice floe had traveled more than a mile, past Glensheen Mansion, by 1 p.m.

"There's thousands of dollars of worth of stuff out there altogether," Porter Smith said.

"And my beer," mourned another angler. A fire official took down anglers' contact information and said they would try to recover the equipment.

Though he hopes Tuesday's episode was a once-in-a-lifetime experience, Porter Smith said he'll be back to fish on Lake Superior in the future.

His cousin, John, added: "Just not for a while."