Hello,

I would not want to be in the path of the ice dam burst. I first heard about Lake Missoula a few years ago from an uncle who lived in Missoula. (now dead).
This is a good web site on it, if anybody has not seen it. Various methods of dating the floods, including C14 and re-deposition Mt St Helens ash falls.

Here's a bite, awesome....

The glacial lake, at its maximum height and extent, contained more than 500 cubic miles of water. When Glacial Lake Missoula burst through the ice dam and exploded downstream, it did so at a rate 10 times the combined flow of all the rivers of the world. This towering mass of water and ice literally shook the ground as it thundered towards the Pacific Ocean, stripping away thick soils and cutting deep canyons in the underlying bedrock. With flood waters roaring across the landscape at speeds approaching 65 miles per hour, the lake would have drained in as little as 48 hours.

Glen

• Lake Missoula