As long as Utah slopes get plenty of "the greatest snow on Earth," the state should be able to weather the national decline in tourism expected as a result of unstable economic conditions.

That's the opinion of travel industry experts in the state, who say more tourists than ever are still likely to visit Utah this winter despite the threats of a war in the Middle East and a national recession at home."You give me the snow and I'll guarantee you the skiers," promised R. Thayne Robson, director of the University of Utah's Bureau of Economic and Business Research.

So far this season, there has been enough snow for several resorts to open at least some runs by Thanksgiving Day although the snow didn't come soon enough to fill the slopes with out-of-town skiers.

Because the first major winter storm didn't ready the resorts until Thanksgiving week, resort operators said there wasn't enough time for many would-be visitors to plan a trip.

Now that there's snow on the ground, the resorts are anticipating a good Christmas. The year-end holiday can be one of their busiest times - if there is enough snow. Last year, several resorts were unable to open by Christmas.

"Everyone is on schedule at this point. But a lot can happen between now and Christmas," said Raelene Davis, marketing director of the Utah Ski Association. "We're keeping our fingers crossed."Robson and other Utah economists have already predicted Utah will not be hit by a recession, although the national economy is expected to suffer at least through the first quarters of 1991.

Nationally, both sun and ski destinations are bracing for a slump in tourism this winter as Americans faced with an uncertain future become increasingly hesitant about spending money on vacations.

Although Utah's $2 billion-plus travel industry is feeling some effects - especially from the rapid rise in gasoline prices since the Middle East crisis began - experts here expect, at worst, only a slowdown in growth.

While the state's most recent attempt at counting visitors was three years ago, the Utah Travel Council said the number of tourists has increased annually. Nearly 11 million tourists were tallied in 1987.

"It's been growing," said Joe Rutherford, spokesman for the state agency, although he said the increases were greater in the late 1980s when low gasoline prices fueled more travel.

"Utah still has some real pluses," Robson said. "We offer tremendous value for the price. Those who get hurt in a recession are the expensive places."

The savings available to Utah visitors, he said, come in accessibility to ski resorts from the Salt Lake International Airport as well as in generally lower prices for everything from hotel rooms to lift tickets.

"My gut feeling is it won't hurt Utah as much as it might some places that are not as accessible," said Utah Travel Council Director Jay Woolley. "Of course, I'm the eternal optimist, but I think we're going to be all right."

So far, Woolley appears to be right about the winter season. The Utah Travel Council is receiving a record number of requests for information about skiing and other winter vacations.

The state has already seen some decline in tourism late this summer, when travel to Utah's national parks dropped off apparently because of the huge jump in gasoline prices.

Last August, the National Park Service recorded a 16 percent overall drop in the number of recreational visits to Utah parks for the month. The biggest fall was at the Glen Canyon National Recreation Area, a 40 percent loss.

While Woolley said he's not overly concerned that the trend will continue, he said the Utah Travel Council is monitoring the effects of fluctuating prices.

"We're keeping a very close eye on it so we can be prepared if gas prices get worse," Woolley said. An option for offsetting any future decline in tourism is an advertising campaign.

"We would do more in-state advertising, emphasizing the shoulder seasons," Woolley said, referring to spring and fall. "We would tell them what they can do with one tank of gas."