A Lancaster County man remained missing Sunday after his kayak capsized in the Susquehanna River late Saturday night.

A search that lasted about six hours was called off early Sunday morning when rescuers started showing early signs of hypothermia, according to Rawlinsville Fire Company Chief Carl Strickler.

"It was pretty cold to be out there for that long," he said.

Jeff Schmidt, the Pennsylvania Fish and Boat Commission's waterways conservation officer in southern Lancaster County, said two Lancaster County men in their early 20s set out on the river in separate kayaks about 10:30 p.m. Saturday.

He declined Sunday to identify either man.

They launched their boats at the Muddy Creek Boat Access in Lower Chanceford Township, York County, as part of a winter camping trip.

"This is not the typical time of year when kayakers are recreating on the river," Schmidt said.

Shortly after the men launched, one experienced difficulty and his kayak capsized, according to Schmidt.

The man's partner tried to rescue his friend, but his kayak tipped over, too.

Schmidt said the second man was unable to save his friend and swam to the York County shore and went to the nearest house to call for help.

That call was made at 11:25 p.m.

According to an interview with the survivor, Schmidt said, both men were wearing personal floatation devices.

"In fact, I'm sure the fact that the one man had his PFD on helped him swim to shore," Schmidt said. "That would have been a difficult swim under the best circumstances."

Strickler said Rawlinsville firefighters launched their boat as soon as they arrived and immediately began searching the river from just below the Muddy Creek access to near the Conowingo Dam.

Both kayaks were recovered, according to Strickler.

Eventually, seven boats searched the river, a K-9 team searched the York County shoreline and a Maryland State Police helicopter scanned from the air using an infrared-imaging device.

Teams involved in the search included crews from the Conestoga, Pequea and Robert Fulton fire companies and from the Harford County, Md., Technical Rescue Team.

"All possible manners of searching were done through the course of the night," Strickler said.

The search continued until about 6 a.m., when Strickler said the cold started to affect rescue teams. No one required medical treatment.

The water temperature was 38 degrees, Strickler said, while the air temperature hovered around the freezing mark.

Strickler did not know Sunday night when the search might resume.

According to Schmidt, the missing man reportedly was an experienced kayaker.

But kayaking at night in late January might have been too much for the paddler to handle.

"River conditions may have been tougher than they anticipated," Schmidt said.

One of the conditions Schmidt cited was the temperature of the water.

"It's hard to imagine that cold-water sudden immersion was not a factor," he said.

When water temperatures are less than 70 degrees, cold-water shock is a major factor in boating fatalities, according to information on the Fish and Boat Commission's website.

The shock causes an involuntary gasp — often resulting in aspiration of water — hyperventilation, breathlessness and a reduced ability to control breathing and to swim, according to the website.

A new law aimed at curbing cold-weather boating fatalities in Pennsylvania takes effect Nov. 1.

Currently, state law requires one personal floatation device (PFD) for each person aboard to be on boats less than 16 feet long, but most people are not required to wear them. Only children 12 and under are required by law to wear PFDs on these boats.

Beginning this year, anyone in a boat less than 16 feet long, or in any kayak or canoe, that's either under way or at anchor, will be required to wear a PFD from Nov. 1 through April 30.

preilly@lnpnews.com