have ever been in a cave before?

Okay, a few of you.

When you think of a cave,

most of you think of a tunnel

going through solid rock.

In fact, that's how most caves are.

Around this half of the country,

most of your caves are made of limestone.

Back where I'm from,

most of our caves are made from lava rock

because we have a lot of volcanoes out there.

But the caves I want to share with you today

are made completely of ice,

specifically glacier ice

as formed in the side of the tallest mountain

in the state of Oregon

called Mount Hood.

Now, Mount Hood's only one hour's drive

from Portland,

the largest city in Oregon

where over two million people live.

Now, the most exciting thing

for a cave explorer

is to find a new cave

and be the first human to ever go into it.

The second most exciting thing

for a cave explorer

is to be the first one to make a map of a cave.

Now, these days,

with so many people hiking around,

it's pretty hard to find a new cave,

so you can imagine how excited

we were to find three new caves

within sight of Oregon's largest city

and realize that they have never been explored

or mapped before.

It was kind of like being an astronaut

because we were getting to see things

and go places

that no one had ever seen or gone before.

So, what is a glacier?

Well, those of you that have ever seen

or touched snow,

you know that it's really light

because it's just a bunch of tiny ice crystals

clumped together

and it's mostly air.

If you squish a handful of snow

to make a snowball,

it gets really small, hard, and dense.

Well, in a mountain like Hood

where it snows over twenty feet a year,

it crushes the air out of it

and gradually forms it into hard, blue ice.

Now, each year more and more ice

stacks up on top of it

and eventually gets so heavy

that it starts to slide down the mountain

under its own weight,

forming a slow-moving river of ice.

When an ice pack like that starts to move,

we call it a glacier

and we give it a name.

The name of the glacier these caves were formed

is the Sandy Glacier.

Now, each year as new snow lands on the glacier,

it melts in the summer sun,

and it forms little rivers of water

on the flow along the ice

and they start to melt

and bore their way down through the glacier,

forming big networks of caves,

sometimes going all the way down

to the underlying bedrock.

Now, the crazy thing about glacier caves

is that each year new tunnels form,

different waterfalls pop up

or move around from place to place

inside the cave.

Warm water from the top of the ice

is boring its way down,

and warm air from below the mountain

actually rises up,

gets into the cave,

and melts the ceilings back taller and taller.

But the weirdest thing about glacier caves

is that the entire cave is moving

because it's formed inside a block of ice

the size of a small city

that's slowly sliding down the mountain.

Now, this is Brent McGregor,

my cave exploration partner.

He and I have both been exploring caves a long time

and we've been climbing mountains a long time,

but neither of us have ever really explored

a glacier cave before.

Back in 2011, Brent saw a YouTube video

of a couple of hikers

that stumbled across the entrance

to one of these caves.

There were no GPS coordinates for it,

and all we knew was that it was somewhere

out on the Sandy Glacier.

So, in July of that year,

we went out on the glacier,

and we found a big crack in the ice.

We had to build snow and ice anchors,

so we could tie off ropes

and repel down into the hole.

This is me looking into the entrance crevasse.

At the end of this hole,

we found a huge tunnel

going right up the mountain

underneath thousands of tons of glacier ice.

We followed this cave back

for about a half mile until it came to an end.

And then with the help of our survey tools,

we made a three-dimensional map of the cave

on our way back out.

So, how do you map a cave?

Well, cave maps aren't like trail maps or road maps

because they have pits and holes

going to overlapping levels.

To make a cave map,

you have to set up survey stations

every few feet inside the cave,

and you use a laser to measure the distance

between those stations.

And you use a compass and an inclinometer

to measure the direction the cave is headed

and measure the slope of the floor and the ceilings.

Now, those of you taking trigonometry,

that particular type of math

is very useful for making maps like this

because it allows you to measure

heights and distances

without actually having to go there.

In fact, the more I mapped and studied caves,

the more useful I found all that math

that I originally hated in school to be.

So, when you're done surveying,

you take all this data,

you punch it into the computer,

and you find someone

that can draw really well,

and you have them draft up a map

that looks something like this.

And it will show you both

a bird's eye view of the passage

as well as a profile view of the passage,

kind of like an ant farm view.

We named this cave Snow Dragon Cave

because it was like a big dragon

sleeping under the snow.

Now, later this summer

as more snow melted off the glacier,

we found more caves,

and we realized they were all connected.

Not long after we mapped Snow Dragon,

Brent discovered this new cave

not very far away.

The inside of it was coated with ice

so we had to wear big spikes

in our feet called crampons,

so we could walk around without slipping.

This cave was amazing!

The ice in the ceiling was glowing blue and green

because the sunlight from far above

was shining through the ice

and lighting it all up.

Now, we couldn't understand why this cave

was so much colder than Snow Dragon

until we got to the end,

and we found out why.

There was a huge pit or shaft called a moulin

going a 130 feet straight up

to the surface of the glacier.

Cold air from the top of the mountain

was flowing down this hole,

blasting through the cave,

freezing everything inside of it.

And we were so excited about finding this new pit,

we actually came back in January the following year

so we could be the first ones to explore it.

It was so cold outside,

we actually had to sleep inside the cave.

Here's our camp on the left side

of this entrance room.

The next morning we climbed out of the cave

and hiked all the way

to the top of the glacier

where we finally rigged and repelled this pit

for the very first time.

Brent named this cave Pure Imagination, I think,

because the beautiful sights we saw in there

were beyond what we could have ever imagined.

So, besides really cool ice,

what else is inside these caves?

Well, not too much lives in them

because they're so cold,

and the entrance is actually covered up with snow

for about eight months of the year,

but there are some really cool things in there.

There's weird bacteria living in the water

that actually eat and digest rocks

to make their own food

to live under this ice.

In fact, this past summer

scientists collected samples of water and ice

specifically to see if things called extremophiles,

tiny lifeforms that have evolved

to live in a completely hostile conditions,

might be living under the ice,

kind of like what they hope to find

in the polar ice caps of Mars some day.

Another really cool thing

is that as seeds and birds land

on the surface of the glacier and die,

they get buried in the snow

and gradually become part of the glacier,

sinking deeper and deeper into the ice.

As these caves form

and melt their way up into the ice,

they make these artifacts rain down from the ceiling

and fall into the cave floor

where we end up finding them.

For example, this is a nodal first seed we found.

It's been frozen in ice for over a hundred years,

and it's just now starting to sprout.

This mallard duck feather was found over 1800 feet

in the back of Snow Dragon Cave.

This duck died on the surface

of the glacier long, long ago,

and its feathers have finally made it down

through over a hundred feet of ice

before falling inside the cave.

And this beautiful quartz crystal

was also found in the back of Snow Dragon.

Even now Brent and I find it hard to believe

that all these discoveries

were essentially in our own backyard,

hidden away just waiting to be found.

Like I said earlier,

the idea of discovery

in this busy world we live in

kind of seems like something

you can only do with space travel now,

but that's not true.

Every year new caves get discovered

that no one has ever been in before.

So, it's actually not too late

for one of you to become a discoverer yourself.

You just have to be willing to look

and go where people don't often go

and focus your eyes and your mind

to recognize the discovery when you see it

because it might be in your own backyard.

Thank you very much.