A driving force: with air travel down in the wake of the terrorist attacks, year-round waterparks are courting motorists to keep attendance levels steady. The industry, meanwhile, remains unsure of the long-term effects.

As the consequences of the Sept. 11 hijacking continue to toy with the world economies, a pervasive uncertainty and collective watchfulness have become almost constant companions. For the waterpark industry, the immediate impact has been somewhat mitigated by the incident's timing.

Most domestic waterparks were either shutting down or were already closed when the terrorists struck, according to Rick Root, president of the World Waterpark Association in Overland, Kan. "We've heard from a few of the parks that were still open that there was an immediate drop in traffic when the attacks happened," Root says. "But since then, the majority of our members have closed ...