Sunday, September 7, 2014

It's already winter on Black Rapids Glacier

Last week we had a quick one-day visit to Black Rapids Glacier. After the wettest summer in Fairbanks since records are being kept, we had another impressive rain fall on the first day of September. Because it was quite cold, Black Rapids got up to 30 cm of snow and looked like the middle of winter. Luckily it was not enough snow to bury our instruments, and when we got there on Wednesday, we had a beautiful sunny day.

Camera used to watch glacial lakes drain. In the background are potholes, left over crevasses from the last surge (1936/37) that are often water-filled.

Thursday, September 4, 2014

Operation Ice Bridge Alaska

 Every year we fly over many of Alaska's glaciers to measure changes in surface elevation. My colleague Chris Larsen has been responsible for this for over a decade now. Recently, this program has been funded through Operation Ice Bridge, a program that bridges the gap left between two orbiting laser satellites (Icesat 1 and 2).
Recently, I've been able to join this program to add a radar component with the goal of measuring the thickness of the glacier ice. For most glaciers in Alaska, we don't actually know how much ice they contain.
The beauty of airborne science is that it can only happen with good weather. Mountain flying poses so many challenges that we have to wait for conditions to be great. Last week we had five days of beautiful conditions and managed to cover a large part of Alaska's glaciers. Some impressions follow below.


Beautiful blue glacier lake

Late fall conditions with only little snow left on many glaciers

A drained glacier lake

Ultima Thule Lodge: our base of operations

The ever-amazing Mt. St.Elias from Icy Bay; 5400 m from bottom to top!

St. Elias with Malaspina Glacier in the foreground

Funky avalanche

Icy Bay

A really nice fold in Icy Bay; St. Elias in the background

Icy Bay

Tyndall Glacier in Icy Bay

Some Moose enjoying the lush vegetation of coastal Alaska
We saw much of the snow surface covered in red algae. This is sufficiently darker than the snow to cause additional melting and snow cups.

Close-up of red snow algea

The Bagley Icefield with Mt. Logan, arguably the largest mountain in the world. The area over 5000 m asl spans more than 15 km.

Pothole central on the upper Logan Glacier. These are believed to be left-over and water-filled crevasses and are associated with surges

A landslide onto a glacier

The advancing Taku Glacier

Band-ogives or Forbes bands, an alternating sequence of dark and bright ice forming under ice falls. This one is from the Juneau Ice Field.

Close up of Forbes' bands.

A large ice berg with runnels in the Columbia Glacier Bay

And finally a nice look at beginning fall in interior Alaska.

Monday, June 2, 2014

Yakutat: a glaciologist's paradise

Yakutat, Alaska, is a small town on the coast. The area around this little town hosts some incredible mountains and glaciers, some of them among the most rapidly retreating in the world, others quite happily advancing. Here are some impressions from our recent flights.

Turner Glacier seems to surge about every 2-3 years. It repeats surges more rapidly than any other glacier I know of. The surges are very violent, and nothing on the glacier remains uncrevassed.

Turner Glacier: the surge advances a front right into the ocean. It is one of the few (if not the only) surging tidewater glacier in Alaska.

Hubbard Glacier is an anomaly in this area: it has been steadily advancing during the past more than 100 years

Strong tidal currents manage to keep this gap open for now.
Hubbard Glacier threatens to close off this gap at Gilbert Point.

Looking out Yakutat Glacier into Harlequin Lake. The glacier has retreated dramatically in the past few years. It might have accelerated in the process, at least it looks much more crevassed than a few years ago

The glacier has separated into two different glaciers recently. The ice in the lake has already broken off and will soon flush out

Tuesday, May 27, 2014

Glacier Bay and the Fairweather mountains

The Fairweather range in Southeast Alaska must surely be among the most spectacular mountain ranges in the world. Mt. Fairweather rises from the Gulf of Alaska to over 4000 m over a distance of only about 20 km and then it drops right back to sea level on its east side towards Glacier Bay (Google maps). The area is heavily glaciated with big glaciers dropping from the peaks to the ocean. The spectacular topography is a result of the very active tectonics of the area with the giant strike/slip Fairweather Fault cutting right along the coast.

Mt. Fairweather. The Fairweather Fault runs along the long straight valley. Alsek Lake is in the foreground

Alsek Glacier and Alsek Lake

Mt. Fairweather with sand beaches in the foreground

Chris and Austin are putting up a GPS base station

Entrance to Lituya Bay. This narrow opening has treacherous tidal currents that have cost many lives, including some members of the first European visitors to the area under La Perouse.

LaPerouse Glacier is the only glacier in Alaska that reaches the outer coast. It has not changed much, in contrast to many glaciers around it. Sometimes, like in this picture, it is separated from ocean by a narrow beach, but sometimes it calves directly into the ocean.

The Glacier Bay altimetry program is quite extensive, and cannot be flown in a single day. So we camped at the beach.

LaPerouse Glacier

LaPerouse Glacier descends very steeply towards the ocean

An advancing glacier in Lituya Bay. This glacier has separated itself from tidewater and is no longer losing mass through calving. As long as it maintains sediments in front of it, it is able to advance.

Lituya Bay. An earthquake in 1958 caused a rockfall into the bay, which caused the biggest recorded wave in history. It reached up to 500 m above sea level. The scar can still be seen on the right side of the image. The lighter vegetation marks the area that was stripped by the wave.

Melbern Glacier and Lake