Luis was last seen on 06/12/1996 when he was swept down Mt. St. Elias near Haydon Peak in Wrangell–St. Elias National Park and Preserve at the 10, 400 foot level during an avalanche. He was taking his turn in keeping the snow from accumulating on the outside of the tent and was caught in the avalanche. The four others were able to free themselves but Luis is still missing. Searches were hampered by high winds and unstable snow conditions.