Benton County deputies are on Beaver Lake after a boater disappeared Sunday.At noon Monday, Lt. Shannon Jenkins told 40/29 News this was likely a "recovery effort" and not a "search."55-year-old Richard Steinbeck was last seen boating in the area of Bear Island on the lake. That night, a witness saw an empty boat and called police.Steinbeck's boat was found, but Steinbeck himself was not on it.Crews searched overnight Sunday into Monday morning, on the lake, the shoreline and at the boat docks.Teams were using SONAR early Monday afternoon and had not deployed the dive team at that point. The timelapse video below shows the search lights of boats overnight.