By Lauren DiSpirito

PINEWOOD SPRINGS, Colo. (CBS4) – The father of two boys who drowned Sunday in the Little Thompson River tried to save them by jumping into the water after them.

The boys’ grandfather, Paul Foreman, says Paul Jacob Foreman, 10, who went by Jacob; and Daniel Foreman, 7, had gone to the river for a picnic with their father, Jeff Foreman, alongside a section known as The Tubs. As Foreman emptied picnic items from his backpack, the boys wandered 40 yards upstream, according to Paul Foreman. When Jeff Foreman lost sight of the boys, he called out to them and searched. Fearing his sons had gone into the water, their father went in after them.

“He did everything he could to save them,” Paul Foreman said.

Paul Foreman says the river’s flow washed his son downstream, where he found his two boys near the water’s edge and performed CPR. Around that time Paul Foreman says word of what was happening reached neighbors who called 911.

The Larimer County Sheriff’s Office says dispatchers received a call that two children had fallen into the river around 12:20 p.m. Deputies, along with local dive teams and other emergency crews from Longmont, Boulder, Estes Park, and the Pinewood and Big Elk fire departments, responded to the scene.

Rescue crews found the children unresponsive and also tried to revive them. The Larimer County Coroner’s Office says both boys died of accidental drowning.

The Tubs is a narrow, rocky section of the Little Thompson River where water pools in what resembles five tubs, which during spring runoff, can become loud and raging with swift-moving water.

Paul Foreman says he doesn’t know how his grandsons ended up in the river, but thinks Jacob might have gone in after his younger brother, Daniel. He says the water was too dangerous and moving too quickly for neighbors to reach Jeff Foreman and try to help.

In January the boys began attending school in Loveland, where their mother lives. Before that they attended school in Estes Park.

Sunday’s picnic was like many excursions the boys had enjoyed with the father, Paul Foreman said. He shared a photograph of Jeff, Jacob, and Daniel taken this winter after building an igloo together in Rocky Mountain National Park.

“His whole life was centered on those kids,” Paul Foreman said. “A totally devoted and dedicated dad.”

Now, he says his son is inconsolable.

“It just happened, it was an accident,” Paul Foreman added, wiping tears.

The family is making funeral arrangements. A GoFundMe page has been established on their behalf.

Lauren DiSpirito is CBS4’s Northern Newsroom reporter. Follow her on Twitter @CBS4Lauren. Share your story ideas with her here.