Larsen: You guys got everything tied down back there?
Truffer: Yep. Christoffersen: Yep.
Larsen: We’re going through the lee of St. Elias, so there might be some turbulence.
Christoffersen: Fasten Seat Belt sign on?
Larsen: Well … who am I to tell you what to do?
[aircraft engine noise, rising music]
[music builds]
[booming sound]
[theme music]
Narrator: There are tens of thousands of glaciers in Alaska,
some stunning cliffhangers, others wide glaciers that come down
to meet the ocean tides. Some, like this one
we flew over in August, are easily visible
from low Earth orbit, and are mesmerizing
from a thousand feet above, and have trees growing on top of their soil-laden boundaries.
Those glaciers – although they represent only a fraction
fraction of the world’s ice – are contributing much more than their share
to sea level rise.
Chris Larsen and his colleagues have repeatedly measured
220 of them in a small single engine Otter.
measuring their height with lasers and their depth with radar,
and watching them change from season to season and year to year.
But Alaskan glaciers
are all so different we’re only just figuring out how they all behave.
Data from flights like these, part of NASA’s Operation IceBridge,
can help fill the gaps.Chris and radar specialist Martin Truffer
are both from the University of Alaska Fairbanks,
and both seasoned Alaskan pilots, but they rely
on their good friend and legendary bush pilot Paul Claus
and his 35,000 hours in the cockpit
cockpit to fly the incredibly demanding flightlines the mission requires.
And does it help you guys being pilots too? Chris: I would like to think so but
but watching Paul fly and seeing what he does is kind of like trying to
learn quantum mechanics in kindergarten.
Truffer: you know, I can fly my airplane around, but just seeing what Paul does in this extremely
challenging environment in the mountains
while trying to follow the specific flight line at a
specific altitude above ground negotiating winds,
topography, maybe occasional low-level clouds
that you have to get around – just managing all that
that is just several levels above
what I could do as a pilot.
Claus: Well, I think the first time I came here to this park I was probably four years old
with my father. I’ve been blessed to be able to fly
fly in lots of places in the world, all over the place actually, almost every continent.
I guess I’m always looking for some place that might be better
than this, but I haven’t found it. [laughs]
Narrator:Paul’s plane is about 60 years old and the first single engine Otter
ever retrofitted with a 1000 horsepower engine,
which make takeoffs feel effortless and gives Paul the ability
to negotiate wild terrain. Which he certainly did during the first
first two incredible science flights of this campaign, and with sunny skies
and relatively calm air, we covered three vastly different pieces of ice.
While Paul fueled up
the plane Chris gave us a preview of today’s science and scenery.
Larsen: So it has one of the greatest coastal
reliefs anywhere in the world. So between
the ocean and the summit of Mt. St. Elias, which is 18,008 feet high,
it’s less than 10 miles. There’s a stupendous amount of mountain
right off the ocean. It’s hard to beat it anywhere in the world.
It might be the prettiest for me. It’s absolutely stunning.
From here in McCarthy we’ll cross one of the bigger
precipitation gradients in Alaska too. Here it’s about
10 inches of precipitation a year and we’ll go over to an area where it’s on the order
of 200 inches per year. So from one of the driest parts of Alaska
to one of the wettest parts of Alaska in about 45 minutes, flight time.
[aircraft engine noise, music]
Truffer: Whoa that’s pretty good. Larsen: That’s awesome.
Do you want to do Tyndall next? Claus: Sure, whatever you want.
Larsen: If the winds are calm now might as well grab it. [laughs]
Narrator: First, we came to the rugged landscape
of Icy Bay, which not that long ago wasn’t a bay at all –
it was filled with ice. Tidewater glaciers in this region
can make dramatic advances and retreats as they feed on high rates
of snowfall and then retreat as they’re melted by warm ocean waters.
Like the Tyndall glacier seen here, most of these glaciers
retreated dramatically over the last hundred years, but nearby
Yahtse Glacier, after years of retreat, is currently the most rapidly
advancing glacier in Alaska.Overall though,
the IceBridge Alaska surveys, from the Denali region in the north,
to the Juneau Icefield in the Southeast, have documented pretty substantial
thinning of glacial ice. Areas seen here
here in orange and red show between about 10 and 15 feet
of thinning per year. Larsen: 1,200
Truffer: That’s a nice waterfall up there from that hanging ice.
Larsen: When we very first started profiling this Paul
this gravel fan and the one in the valley next to it didn’t exist.
Claus: Yeah, I was gonna say. Look at all the good landing spots here.
There was no place to land here before. Larsen: No, it was deep water.
Narrator:After covering several of Icy Bay’s glaciers,
given that it was time for lunch, just like that, we landed
in this unforgettable spot. [waterfall noise]
[engine noise taking off]
Flying eastward, leaving Icy Bay behind,
we came to the mighty Malaspina, one of the Earth’s
great examples of a “Piedmont” glacier, that spills out like pancake
batter onto a broad plane as it approaches the sea.
It surges at uneven intervals, creating dramatic patterns
on its surface as it distorts the moraines of rock and soil
borne along by the glacier. The Malaspina
is less dynamic than the Yahtse and is only melting
at about the average rate for Alaska. But that could change quickly.
Larsen:Has the potential for being one of the bigger geographic evolutions in Alaska
Certainly, my son will be able to witness
some big geography changes there … There’s potential for it being connected
with the ocean through some narrow lagoons, estuaries,
which would take a little bit of coastal erosion, but it’s not too hard
to imagine that this – where the Malaspina Glacier
is now could become a large bay.
Narrator:The data that Martin’s radar provides could reveal how vulnerable the Malaspina is
to melting by the nearby ocean. Here we see the
radar returns from the surface of the glacier, and here is something that Chris’s lasers
can’t see – the rocky bed of the glacier, giving us both
clues as to what’s happening under the ice, as well as a
measurement of its thickness.
Finally, we came to the Yakutat ice field, 300 square miles of absolutely
doomed ice perched high in the mountains.
Researchers even debate how this ice field came to be at all,
Since in its current configuration, it’s hard to imagine how
it could capture enough snow to form glacial ice.
And so even if the Arctic weren’t warming faster than the rest
of the planet, this area would be likely to melt within a century or two.
But with many other glaciers,
, it’s easier to see the connection between a warming planet and ice loss.
Thanks to data from IceBridge and other surveys,
we now have a good estimate of the current rate of loss from Alaskan glaciers
-- 75 gigatons a year.
While airborne observations over Alaskan glaciers have
provided a rich record of change in the area, those efforts
are now augmented by NASA’s newest ice-measuring tool, ICESat-2.
With six laser beamss of its own,
and orbiting the Earth every 90 minutes, the satellite
will carry on the record of Alaskan change.
For their part, Chris and his team will continue to do their surveys for at least
the next two years, helping to validate the ICESat-2 data,
and make further detailed observations over the stunning glaciers of Alaska.