Questions remain for the National Park Service in setting up a similar system, including the cost, not only in dollars — estimated in the $200,000 range — but in the effect on the wilderness. "There will definitely be some environmental degradation to the park," Tribble said. How much degradation may be the key to whether Haleakala park officials proceed. The mission of the National Park Service is to protect natural wild areas for public access. Would a series of sirens and gauge stations ruin the wilderness experience for visitors? Would people even know what to do when they hear a siren? Haleakala Superintendent Don Reeser said park officials have discussed a warning system but never pursued the idea. It's uncertain whether such a system would have saved the Browns, he said, since they were hiking about a half-mile up from the famous coastal pools and visitor center. The flooding caught just about everyone by surprise, even the National Park Service, which posted a flash-flood warning only minutes before the hikers were swept downstream. Nevertheless, Reeser said, the park needs to revisit the issue.