Enlarge / The Kalalau Valley between sheer cliffs in the Na Pali Coast State Park on the western shore of the island of Kauai in Hawaii, United States. This view is from the Pihea Trail in the Kokee State Park. (credit: Getty | Jon G. Fuller) The Hawaiian island of Kauai may not have any spewing lava, but hikers along the magnificent Napali coast have brought their own volcanic action recently, violently hollowing their innards amid the gushing waterfalls and deeply carved valleys. Between August and early September, at least 50 hikers fell ill with norovirus along the famed Kalalau Trail, which has been closed since September 4 for a deep cleaning.