Monday, August 26, 2013

Swiss glaciers

Last week I had the great opportunity to fly with a friend along the Swiss Alps and see some glaciers from the air. Ok, so this is not field work in the strict sense, but the pictures are nice anyway ...

The Claridenfirn is site of one of the longest mass balance series on Earth

Two groups of climbers crossing the Claridenfirn

The retreat of Rhonegletscher is exposing a new lake. In the shadow one can see an area of the glacier that is covered in white tarp to reduce melting of ice and protect an ice cave.


The upper Rhonegletscher still has a fair amount of snow on it, because of a very snow rich winter 2012/13. However, high temperatures in the summer have melted most of this snow.

Unteraargletscher has retreated dramatically, like so many other glaciers in the Alps. The lower glacier is now entirely dirt covered.

Aletschgletscher is the biggest glacier in the Alps and still a magnificent sight.

The tongue of Aletschgletscher

Riedgletscher with Mischabel mountains. My home town is located at the bottom of this glacier

Turtmanngletscher with the magnificent Weisshorn

A rockglacier in the Val d'Anniviers is flowing into a glacier.

Gornergletscher with Monte Rosa

Findelengletscher. This was the field site for my diploma thesis, but most of the study site has melted away in the past 20 years.

Tuesday, July 9, 2013

Black Rapids lake drainage

This was a quick trip for me to help set up some surveying instruments on Black Rapids Glacier. We were here to watch the effect of a draining lake. From past measurements we know that the glacier can start flowing 2-4 times faster when water reaches the base. We wanted to see whether such a speed-up can also draw in ice from a big tributary glacier.

Aurora Lake, full to the brim, and ready to drain. This is the biggest of the marginal lakes.
The upper Black Rapids Glacier has many of these potholes, old crevasses that often fill with water and then drain.

Looking up Black Rapids Glacier
Mt. McGinnis

Our surveying equipment: An automatic theodolite and a precise radar that allows us to measure deformation fields in the entire field of view.


While checking out various instruments, we had an opportunity to hike around the glacier. It's always nice to see the signs of life in the harsh conditions of the mountains.
A plugged up moulin; this hole leads right to the bottom of the glacier!

A ptarmigan nest ...

... and mama ptarmigan whom I inadvertently chased off her nest.

A panorama showing the Loket tributary as it enters the main valley of Black Rapids.
video
I recorded this video as I hiked out the glacier. Near the glacier front, water comes up from underneath the glacier and creates these big waves.

Sunday, June 9, 2013

The Stikine Icefield

Part of our recent survey took us down to the Stikine Icefield, Alaska's southernmost icefield. Its southern location and relatively low elevation make it vulnerable to changing climate, but this can be offset by high rates of snowfall. The icefield has several glaciers that reach the ocean, among them LeConte Glacier, the southernmost tidewater glacier in the northern hemisphere. Many of the tidewater glaciers have retreated very rapidly in the past few years.

The icefield is spectacular with many impressive spires, most famously Devil's Thumb.

Sawyer Glacier calving into a very narrow fjord

The famous Devil's Thumb with Cat's Ears and Witches Tit to the right.

Devils Thumb through a gap

Witches Cauldron: This is a really weird place where glaciers flow in from several sides and just kind of disappear. It's where glaciers go to die...

Devil's Thumb with shadows of the Cat's Ears

Burkett's Needle

The picturesque fishing town of Petersburg

What are you looking at?


Dawes Glacier (I think). The trimlines show the extent of recent ice loss

A cruise ship in Tracy Arm

Friday, June 7, 2013

Surging glaciers

While we were surveying glaciers in several mountain ranges, we had the opportunity to watch a vast variety of glaciers. While many are rapidly retreating, some are advancing and a few are experiencing a glacier surge. This is a phenomenon where a glacier increases its speed by a factor of ten or more for several months. It only happens on very few glaciers. Glacier surges happen periodically, every few years on some coastal glaciers and every few decades in the Alaska Range. So it's always a special treat to see one.

Turner Glacier (coming straight at us, across the bay) is the only tidewater glacier in Alaska that is surging. It has an unusually quick repeat cycle and this is its third surge in the last ten years.

The broken surface of Turner Glacier near its front

We noticed unusual crevasses on the Logan Glacier in March, and now they are even more pronounced.

The surge does not produce crevasses across the entire glacier, but there are distinct crevassed bulges on the side that indicate fast flow.

Logan Glacier

This is the Robertson or the Johnson Glacier in the Alaska Range. It is not known to surge, and I don't believe this is a real surge. But that fresh shear crevasse running along several kilometers is something I've never seen before on a glacier.


Monday, June 3, 2013

Avalanches

One of the amazing things on this last trip was the very large number of avalanches that we saw, wherever we went. There were avalanches in each mountain range and at every exposition. Some of them with run-outs like I've never seen before.

Everything has slid here.

Individual snow rafts seem to glide well into the flat parts with very little friction. They look more like mudslides.

Amazingly long run out (it continues well into the shadow)

Look at the crown on the one on the left. We estimated it at well over 5 m!

An avalanche with crevasses? That says something about how active the glaciers are.

Sunday, June 2, 2013

Airborne surveys in Alaska

We spent a wonderful two weeks at Ultima Thule Lodge in the Wrangell St.Elias mountains. Our goal was to do airborne glacier surveys all over Alaska. We run LiDAR surveys to measure how glaciers change over time and radar surveys to measure how thick they are. The program did not start well. Interior Alaska experienced one of the coldest springs ever recorded and the mountain weather was not very conducive to flying. But by the second week it warmed up and the weather finally cleared. Within just a few days I got to see some amazing mountains. Sometimes I think that by now I've seen a lot of the mountains of Alaska, but this trip showed me (again), that there is still so much more to see and do. Below is a selection of somewhat random pictures; I took more pictures on this trip than on any previous field trip ...

The Root Glacier near McCarthy with the stairway ice fall in the background. This is one of the largest ice falls in the world.


Paul Claus's Single Otter

A medial moraine

The beautiful moraines of the Kaskawulsh Glacier in Kluane National Park

Mt. St.Elias, at over 5,400 m one of North America's tallest mountains. In the foreground Malaspina Glacier

The beautiful sand beach by Yakutat and Mt. Fairweather in the background.

The front of Hubbard Glacier, North America's longest tidewater glacier, and one of only a handful of advancing glaciers.

Looking almost 100 km down the Fairweather Fault (the extension of the San Andreas Fault). In the background is Mt. Fairweather.

Hubbard Glacier and Gilbert Point. The healthily advancing glacier is threatening to build an ice dam at this location. It has happened twice already, in 1986 and again in 2002.

The fronts of Logan and Chitina Glaciers

The alien landing site: A glacier sinkhole.

Mt. Logan is a massive mountain. It is just short of 6000 m high, and quite possibly the most massive mountain on Earth.

Hole in the Wall Glacier: This is an overflow of another advancing glacier: Taku Glacier in the Juneau Icefield. This glacier did not even exist 150 years ago!

Taku Glacier