Sometimes tourists ask Effie Yazzie what happened on the day a flash flood suddenly ripped through Lower Antelope Canyon, killing 11 people at the tourist attraction near Lake Powell.

She doesn't go into detail."There are certain things that I'm not allowed to discuss," says Yazzie, manager of the Navajo-run park in northern Arizona where the canyon lies.

One reason is that she doesn't want to scare off tourists, who have traveled to the canyon from all over the world since the Navajo Nation opened the park three years ago.

They're drawn to the twisting, rainbow-colored walls, so close in places that you can touch both sides. And the location is right, too - the canyon empties into Lake Powell and is a short trip from Las Vegas.

Yazzie and local tour guides say tourists are back to their old num-bers.

But business isn't the only thing keeping Yazzie from telling tourists all about the flood of Aug. 12, 1997.

The Navajo see the flood as an unpreventable tragedy, something that is best not discussed, says Clarence Gorman, director of parks and recreation for the tribe.

"We don't talk about it that way. It's passed and it's a tragic event that happened," he says.

But the families of some of the dead say the tragedy was preventable. And they hold the tour company that brought their relatives to the canyon responsible.

Five of the hikers who died were on a tour with TrekAmerica, a tour company owned by Premiere International of Carson City, Nev. The families of three of them filed suit against Premiere and Trek-America in February.

The suit, which seeks unspecified damages, alleges that tour guide Francisco Quintana allowed tour members to enter the canyon despite the danger of flash flood.

TrekAmerica West Coast Area manager Harry Antoniou said Tues-day that company officials wouldn't comment or make Quintana available for an interview because of the lawsuit. Quintana didn't return a call to his home in Citrus Heights, Calif.

Attorneys for the company have filed court papers saying the tribe is actually responsible for the deaths. They say that because the hikers were on tribal property, the tribe was responsible for their welfare. A company attorney declined to discuss the suit.

Gorman says the tribe isn't worried about being sued, but he declined to elaborate.