FREMONT COUNTY, Colo. -

Authorities said they can't explain why there have been at least 13 drownings and related deaths on Colorado waters this year, including three in the past week in Fremont County.

Capt. Don Pinover, of the Fremont County Sheriff's Office, said of the three recent victims, two were rafting at the time -- one apparently had a pre-existing breathing problem -- and another was trying to rescue his dog from the water. 

Pinover said the victims may have underestimated the power of the current at this time of the year.

"There is no explanation for it," he said.  "I don't know how you'd describe it.  We can't believe it.  Every time we get a call, we just say it can't be another one.  We're just hoping this is the end of it for the summer."

Pinover said he's especially worried about children who could easily be swept away in the river.  He advised parents to keep children away from the river, and for adults to avoid being in the river alone.

The recent tragedies have been "blown out of proportion" but apparently aren't discouraging tourists from taking rafting trips, said Jim Wick, owner of Lost Paddle Rafting in Cañon City.

Both recent rafting victims were wearing safety equipment but still died.  Wick said outfitters provide all rafters with equipment and brief them on safety procedures before anyone gets into a raft.

"We tell people, if you fall out of the boat, you swim, and you swim aggressively," Wick said.  "The river's pretty narrow.  It's pretty easy to get out of, for the most part.  Just a good, solid doggie paddle and you can get yourself out."

The Mendoza family from Dallas, Texas, made their first rafting trip to the river Wednesday and said they weren't worried about safety.

"We know our boundaries," said father and husband Gerry Mendoza.  "Safety is very important to us."