[VOA]

What's most interesting to me is how far out the water line receded to.

I heard a radio report that cited the story of a Swedish family group printed in
The Washington Post.
I think they were on one of the beaches in Thailand.
The father of the family said that the water seemed to recede about 2000 yards in
"what seemed like 15 seconds", leaving an exposed seabed with flopping fish.

Then the wave rushed in; the family lost a niece in their race to survive, IIRC.

I heard a tsunami expert say that in extreme cases, the receding of the water
(prior to the hit of the wave) can be so far out that a person standing on the beach
will lose sight of water (i.e., recede to the horizon).

[BobS]

There is a way to survive these things. It's not by standing around gawking. You must hyperventilate your lungs and take a deep breath and dive directly underneath the wave, staying as close to the bottom as possible. After the energy passes above, you can swim up.