MADRAS, Ore. -

A plane flew over the lower Deschutes River and an Oregon State Police jet boat assisted Wednesday in the fourth day of searching for a missing fly fisherman who slipped into the water near the Trout Creek Campground and apparently drowned Sunday night.

On Tuesday, the search sadly moved from rescue to the recovery of Steven Wayne Adams, 54, of Lahaina, Hawaii, who apparently lost his footing and drowned.

Jefferson County Sheriff Jim Adkins said a Madras search and rescue volunteer flew his plane over the area Wednesday and the jet boat went up and down the river, but found no sign of the missing man.

Starting Thursday, "we're going to start having one of our seasonal deputies floating that river every day," the sheriff said. "We're going to have a bigger search, maybe with a bunch of floaters Saturday. But we just don't know what else to do."

Adkins said they have been in regular contact with Adams' father, Lester Adams of Prineville, about the search effort.

Adams' sister, Leslie Adams, shared a photo of her brother Tuesday. It was taken as he donned his fishing gear that evening, just minutes before he lost his footing while fishing and was swept into the river.

"I saw him go down, struggle to regain his footing, and then saw him swept into the center of the current," she said, also expressing appreciation to search crews for their work.

Family friend Joseph Marshello of Bend said Adams, an Oregon native who grew up in Portland, was an avid fly-fisherman who had vacationed at Trout Creek Campground for 35 years with his late wife, Connie, who died a year ago.

?Last September, he spread her ashes there,? Marshello told KTVZ.COM

Marshello explained that what some witnesses thought was a ?walking stick? actually was a brace ? a third leg of sorts ? many fly-fishermen use to prop them up in the river, allowing them to stabilize themselves against a swift current.

On Sunday night, Marshello said Adams ?had attempted to catch one more fish for dinner ? he caught one for breakfast.?

?Something happened ? he slipped, there was a loud splash. My wife stood up, saw him struggling. Leslie saw him struggle, go face down. She?ll never forget the look on his face when he knew what was happening.?

The sheriff?s office had boats back in the river Tuesday, searching from the Rainbow boat launch to South Junction.

?The family is pretty broken up about all this,? Adkins said, and is asking fishermen in the area to keep a close eye out for anything unusual in the water.

Late Tuesday afternoon, Adkins said eight boat crews had just finished their day searching the river, as well as two crews on the river banks, but Adams again was not found.

"We're re-evaluating, trying to make plans for the coming week and the coming weekend," he said.

Dozens of searchers from several agencies conducted a major search on and along the lower Deschutes Monday for the missing man.

Sheriff?s office Capt. Marc Heckathorn confirmed the sheriff?s office got word of the incident around 9 p.m. Sunday.

Witnesses told deputies they saw the man in the water, heading downriver past the boat launch at the campground, located where Trout Creek flows into the Deschutes near the Jefferson-Wasco County line, northeast of Warm Springs and north of Madras.

Campers were questioned in an effort to narrow the initial search area, an effort hampered by darkness. Warm Springs officials called in boats to assist in the search. Warm Springs and Oregon State Police also were assisting, along with the BLM.

About 75 searchers spread out by plane, ATV and boat Monday, covering a 30-mile stretch of the Deschutes.

It was a terrifying day for the man's family as searchers scoured the river and its banks, in hopes he could still be alive.

His sisters, father, stepmother and friend, still in shock, said they had been camping together since Friday. Around 9 p.m. Sunday, something happened.

"People saw him flailing in the water and then lost sight of him as he was going downriver," Heckathorn said. "And no one has seen or heard from him."

Heckathorn said searchers were scouring the river banks while others worked on the water in kayaks, inflatable boats, drift boats and motorized boats as well. The Lower Deschutes is usually closed to motor boats, but they were allowed for Monday's search, he said.