“I knew your policeman's logic would come into play. Two reasons. Time and distance. The time between waves hitting the beach is five to twenty seconds. With a tsunami, that time can be ten minutes to two hours. The distance between waves is called the wavelength. Beach waves can be three hundred to six hundred feet apart. With a tsunami, you're talking three hundred miles-plus.”

“I've seen some pretty destructive beach waves.”

“So have I. But even an ordinary wave crashing on the beach only has a short life and a speed of ten to twenty miles per hour. Your tsunami has had hundreds of miles and hours to build up its energy. The deeper the water, the faster the wave. That's why a tsunami can hit six hundred miles per hour as it crosses the ocean, even though ships don't feel it and you can't see it from the air. Let me give you an example. In 1960, an offshore quake near Chile sent a wave across the Pacific. The wave was no more than three feet high. Twenty-two hours later, when the wave hit the coast of Japan, it was twenty feet high and killed two hundred people. The waved bounced around the Pacific for days, causing damage wherever it touched.”

“If it's only a ripple in the ocean, how'd you figure this was going to be a big one?”

“I was lobstering out on the ledge where it's comparatively shallow. The wave slowed down when it hit the shallows and started to peak. It was moving slower, but all the energy it built up was still there. That energy has to go somewhere. When the wave approaches shore, the mousy little sea grows up into a monster. Sometimes it builds up into a great towering wave. It might be a bunch of series of breaking waves, or a bore, like a bunch of steps with a steep breaking front. It might suck out the water and spit it back out.”

“That's what happened with us. Like someone pulled the plug out of the harbor.”

Jenkins nodded. “Tsunamis are fascinating and very adaptive critters. Reefs, bays, entrances to rivers, can affect the damage, the slope of the beach. The waves can crest to one hundred feet or more, but mostly they just surge. All depends on what's in the way. They can wrap around a headland and cause damage on the opposite side of an island. When they get squeezed, they become really dangerous, because you've got all that intensity built up in a small space.” He pointed out the window at a river that fed into the harbor. The high banks were littered with debris. “They can even go up rivers, as they did here.”