SHERIDAN, Colo. — A 20-year-old ex-Marine remains missing after falling into the South Platte River while he was tubing.

The accident happened in the part of the river known at the Union Chutes, where the water is running high and very fast. The Sheridan Police Department announced Sunday the search for Joe Goodwin had been suspended.

Several witnesses attempted to rescue Goodwin but were unable to do so because of the swift current. He was last seen about one-quarter mile north of Union Avenue floating in the river.

Goodwin served as a Marine and his family said they hope for a miracle.

Sheridan police are discouraging tubing and rafting activities in the South Platte River because of swift water conditions.

Goodwin was with three friends, braving the high waters to have a good time. Fire and police teams searched the river and its banks using boats and ATVs, and Goodwin’s friends helped with the search.

Search teams are asking everyone to play it safe and stay out of the water.

“It’s just not safe. It’s just too fast,” said Melissa Taylor with the Denver Fire Department. “When trained professionals can’t get in the water, go to your local pool and be safe that way.”

In a statement, Goodwin’s family said: “Joey Goodwin is loved by all.  He is an energetic, courageous, caring, strong young man who is always smiling.  He loves living in Colorado and enjoying its recreation.  He loves his family, friends, girlfriend and Jesus.  He served as a Marine and has always been dedicated to serving others. At this time all we know is that he was tubing with some friends and fell into the river.  We are trusting God for a miracle and asking for prayer that he is found quickly.”

Goodwin was last seen wearing orange shorts.  He is a 2013 graduate of Heritage High School.

Police said they will not resume the search unless they have credible information because the conditions are too dangerous.