PROVO — After five days of searching, officials only have a few soggy clues regarding the whereabouts of a missing boater who capsized Monday night in Utah Lake.

They found Lon Thongthipvoravong's flip-flop sandal and his fishing bag. Then they discovered the sunken, upside down tri-hull boat.

But despite hours and hours of searching using highly technical sonar equipment, rescuers packed up Friday afternoon, still without any signs of the 32-year-old Laos native from Orem.

Thongthipvoravong was boating with five friends Monday when a storm brought on waves that sank their boat and left the men clinging to anything that might float while they tried to swim to shore. There were life jackets on the boat, but they went down with the boat.

The other men were rescued within eight hours, but Thongthipvoravong never made it to shore.

Friday's search began early but was called off around 2:30 p.m., due to an incoming storm, said Utah County Sheriff's Lt. Dave Bennett. Winds make the use of the sonar equipment nearly impossible, and officials don't want to put their rescuers in danger on potentially choppy water.

Bennett said crews plan to resume searching Saturday morning, relying on the aerial views from the airplane and the side-scanning sonar boat.

Officials were hopeful that the rising temperature of the water would make it easier for Thongthipvoravong's body to rise to the surface, but the rainy weather has made searching difficult.

The search is still focused two to four miles north of the state park and west of the Links at Sleepy Ridge golf course, where the boat and other personal items were found.

During a Utah Lake master-plan-adoption ceremony Friday, officials commented on the tragedy.

"While we're celebrating today this great accomplishment, I want to offer my condolences to the family of (Thongthipvoravong), who is missing on the lake," Dick Buehler, Director of the Utah Division of Forestry, Fire & State Lands. "Utah Lake is a great resource. It can also be also be one of those things we have to take extra caution on."

Contributing: James Davis

E-mail: sisraelsen@desnews.com