Heavy rains fell yesterday, hours after an army of student volunteers raised crumbling dikes three feet above river levels to stave off disaster in this flooded city of 172,000.

At least 9,000 people already are homeless because of the flood waters, and forecasters expected as much as two more inches of rain by tonight.

No deaths have been reported during six days of flooding on three rivers winding through the city but damage estimates were placed at $20 million.

"The kids have been working out here all night long and it is pretty stable now. We're all just taking a deep breath and waiting and gearing up for the rain," Mayor Winfield Moses said after a mile walk along a dike.

Army and Air National Guard troops and some state police troopers were watching the dikes. Guards were standing on sandbags all over the city as skies darkened.

"I am told for every half-inch of rain that adds six inches of water to the river level," Moses said. "We surely do not need that. If we get an inch of rain we're in trouble. If we lose the dike and do not have a secondary line of defense . . . we would have a flash flood the likes of which this city has never seen."

Meanwhile, a tornado swirled through the Oklahoma Panhandle early yesterday, injuring five people, and heavy thunderstorms drenched western Kansas and the Texas Panhandle, spawning twisters near Channing, Tex., and Liberal, Kan., the National Weather Service said.