CNN was interviewing a diver who was lucky to still be onboard a boat (helping his sons gear up) when the captain spotted the waves. The capt. fired up the engines and got the boat away from the rocky cliffs they were near.
Horridly, the diver said that many snorkelers from their boat had already entered the water and entered a nearby narrow cave where the water normally is about 3 ft. from the ceiling. Obviously, the tsunami filled the cave and gave the snorkelers no refuge.
It's all a nightmare, but this was particularly horrifying to me.
if the cave air had no outlet above the water, perhaps the pocket of air persisted when the water level rose.