One person was killed and six others went missing in Kenya when a flash flood in a gorge at a national park caught a church youth group off guard, rangers said Sunday.

The incident occurred late Saturday in Hell's Gate, a park near the city of Naivasha known for its walking safaris as well as spectacular gorges, volcanic outcrops and geothermal steam.

"One body has been retrieved while search efforts to account for the missing six are ongoing despite the darkness in the gorges," the Kenya Wildlife Service said in a statement.