A University of Hawai'i medical student is among those bagging and piling sandbags in a desperate effort to hold back Iowa floodwaters that have thousands of people seeking higher ground.

Stephen Chun, 25, a third-year medical student at the UH John A. Burns School of Medicine, Chun, has been working on a research project about pancreatic cancer at the University of Iowa at Iowa City. Today, he is part of the effort to hold back waters from the Iowa River.

"The main shopping section of the city is 5 or 6 feet under water," he said in a telephone interview tonight. "A thousand volunteers turned out today and yesterday to fill and stack sandbags. We're going to lose some buildings at the university. We've been removing books from the library. We are taking in patients at the university hospital from Cedar Rapids and towns that are flooded out all over the state."

Chun, a Punahou School graduate who was born in Hawai'i, said the volatility of Midwestern weather has amazed him.

"We were out sandbagging today," he said. "And it was bright sunshine, hot, about 80 degrees. Suddenly, the temperature dropped about 20 degrees in almost no time. It rained and then it started hailing. The sky turned green and the tornado sirens were going off. We saw a funnel cloud coming at us and we all had to go inside, but fortunately it didn't hit us."

He said at times the effort seems futile, and compared trying to stem the flooding to treating a rapidly spreading cancer.

"I don't know the exact measurements but it seemed like the river rose 2 or 3 feet in just a few hours. We're trying really hard, desperately hard to save things, to fight this," he said, "but, gosh, look at the odds. A thousand people stacking sand bags but it still looks like we're going to get flooded. Entire cities are being flooded."