A father and three children are dead following a kayaking accident off Lake Superior's Apostle Islands.

Their boat capsized Thursday night between Stockton and Michigan islands while the family was vacationing on Madeline Island, just off the coast of Bayfield, Wis., about 85 miles east of Duluth.

Authorities identified the father as Eric Fryman, 39, of Loyal, Wis. The mother, who survived, was identified as Cari Mews, 29.

Obituaries posted over the weekend identified the children as Kyra, 9; Annaliese, 5; and Jansen, 3.

It's unclear exactly when and from where the group set off on Madeline Island, and which part of Michigan Island they were attempting to reach. The shortest distance between the islands is 3 miles.

The family was heading to Michigan Island when the boat took on water, capsized and sank, Wisconsin Public Radio reports.

"The father tried to swim to Michigan Island with the children and the mother remained with the kayak," U.S. Coast Guard Master Chief Alan Haraf told WPR. "At some point, she got separated from the kayak."

Around 4 p.m. Thursday, the family tried calling and texting for help, according to WPR.

Mews sent text messages to her sister reading "911" and "Michigan Island," according to local police.

However, the texts didn't go through until five hours later because phone service was so weak, WPR reports.

Mews' sister then called Ashland County emergency dispatchers around 8:30 p.m. Thursday and the rescue efforts began. The search and rescue operation involved a helicopter and research ship, the Daily Press reported.

Police said strong thunderstorms hindered search efforts.

Fryman and two children were found just after midnight, the Ashland County Sheriff's Office said in a statement Friday.

Authorities recovered the third child's body around 10 a.m. Friday.

The Ashland County Sheriff's Office and the offices of two local coroners are investigating the incident. Authorities haven't commented on exactly what caused the accident or causes of death.

Ashland County Sheriff Michael Brennan told Wisconsin Public Radio on Friday that authorities were trying to locate the kayak as part of their investigation "to see if there is any structural damage or anything that would've caused it to take on water and capsize."

Even late in the summer, Lake Superior surface water temperatures rarely get warmer than 60 degrees, according to the National Park Service. The average annual temperature is 40 degrees.

At a 60 degree water temperature, symptoms of hypothermia can begin in two hours or less, according to the University of Minnesota's Sea Grant office.

Correction (Sept. 2, 2018): An earlier version of this story incorrectly spelled the name of Eric Fryman.