- [Teacher] What does it mean to be curious?

(Teacher gasps) For my students, curiosity creates opportunities for a bigger and brighter future.

(upbeat music) (gentle music) - Have you heard of Moses Coulee here in Eastern Washington?

A little town here called Palisades, which means line of cliffs.

And if we carefully study these cliffs, we can tell a story of how this canyon was created.

It's a tale of two canyons, one carved slowly before the Ice Age and one carved quickly during the Ice Age.

But both canyons are the same canyon.

(gentle music) (bright music) The hanging valleys of Moses Coulee are really spectacular.

That's a little V-shaped guy hanging way above the floor of Moses Coulee.

Now sometime you're in a glaciated scene and the hanging valleys are a little U's.

This is a little V because there was a stream, once upon a time, that was flowing all the way, gradually, down to the major floor of a V-shaped river valley.

That was the story long ago with Moses Valley, a river canyon.

But then the Ice Age floods happened tens of thousands of years ago, and a huge flood of Ice Age flood water, maybe multiple floods came through, sheared off the cliffs.

And suddenly our gradual stream is now perched high and stranded 900 feet above the floor of today's Moses Coulee.

Hanging valleys help us see the pre-glacial portion of this story.

(bright music) So the question is, what did Moses Coulee used to look like?

And this is a river canyon just a few miles to the north, and it's probably a pretty good representation of what Moses Coulee used to look like.

This is Rock Island Creek Valley.

Notice that there's a V shape and all the side streams are working their way gradually to the valley floor.

There's no Ice Age flood history in here.

This is a simple river valley from tectonic uplift gradually against these streams, both major and minor.

This is what Moses Coulee used to look like.

There was already a big valley where Moses Coulee is today.

And the floods simply modified a V-shaped valley into a box shaped valley.

And that gets us our hanging valleys.

(bright music) So these aprons of talus in the walls of Moses Coulee are spectacular, and they are a function of the Ice Age floods.

Before the Ice Age, these aprons of talus were not here.

It was a gradual V all the way down to the bottom.

But you get talus like this only when you get an absolutely sheer vertical cliff.

And that sheer cliff was created by the floods quickly.

And then since the Ice Age floods, rock by rock, these angular pieces are tumbling down and decorating the lower half of the walls of Moses Coulee.

These are post Ice Age flood, talus deposits, but there'd be no talus if we never had the Ice Age floods coming through.

(bright music) Well, you know, sometimes this geology thing is just observation and a little bit of logic thrown in.

We've done that today with the hanging valleys and the V-shaped notches along the walls of Moses Coulee.

We've also done it with the talus aprons along the sides.

That was done a long time ago by geologists coming through here and we still value those observations.

The tale of two canyons, an older story pre-Ice Age and a younger story, Ice Age floods, both stories are here in Moses Coulee.

(bright music) - [Narrator] This series was made possible in part with the generous support of Pacific Science Center.