Mahsa Icefield Retreat and Separation, Baranof Island, Alaska

The Mahsa Icefield is at the headwaters of Takatz Creek.  This is a small glacier, not an actual icefield.  Five kilometers to the west is another small unnamed glacier at the headwaters of Sawmill Creek.  Here we focus on changes in the two glacier using Landsat images from 1986 to 2014.mahsa icefield ge

Google Earth image

In 1986 the Mahsa Icefield is a contiguous glacier that extended 5 km from east to west, red arrow indicates  the mid-section of the icefield.  A separate glacier in Sawmill Creek, yellow arrows, was 2.1 km long and has no lake at its terminus.  In 1997 the Mahsa Icefield has separated into an east and west half, at the red arrow, and has lost all of its snowcover.  The glacier in Sawmill Creek is still a single ice mass, but has lost all of its snowcover, which happened in 1998, 2003 and 2004. In 2014 the Mahsa Icefield’s east and west half are separated by 300 m, red arrow.  There is very little snowcover remaining despite there is a month left in the melt season.  At the headwaters of Sawmill Creek a lake has formed as the glacier has retreated, the lake is 600 m long in 2014.  The glacier has also separated into a small upper and lower section.  This glacier has lost half of its area since 1986.  The retreat of these glaciers on Baranof Island is similar to the retreat of nearby Carbon Lake Glacier,Lemon Creek Glacier, and Sinclair Glacier. Lemon Creek Glacier has lost more than 25 m of glacier thickness during the 1953-2014 period when its mass balance has been observed by the Juneau Icefield Research Program, and has retreated more than 1 km (Pelto et al, 2014).

mahsa icefield 1986

Landsat image 1986

mahsa icefield 1997

Landsat Image 1997

mahsa icefield 2014

Landsat image 2014

 

Weddel Glacier Thinning-Retreat, South Georgia Island

Weddel Glacier is on the southeast coast of South Georgia Island.  It terminates in Beaufoy Cove just north of Gold Harbor.The change in glacier terminus position has been documented by Alison Cook at British Antarctic Survey in a BAS retreat map.  In 1958 it reached within 400 m of the coast at the outlet of Beaufoy Cove. Gordon et al., (2008) observed that larger tidewater and sea-calving valley and outlet glaciers generally remained in relatively advanced positions until the 1980s. For Weddel Glacier the retreat was rapid from 1960 to 1974 and was slow from 1992-2003.  Here we examine Landsat imagery from 1989 to 2015 to visualize and update this change.
bertrab ge
Google Earth Image

weddell-bertrab map
BAS map of glacier terminus position

In 1989 the glacier terminates near the tip of a peninsula, red arrow in each image. The calving front extends southeast, orange dots. At the yellow arrow the glacier fills a small side valley adjacent to the main glacier. At the purple arrow is a small extension of the main icefall flowing down the bedrock step.
In 2002 there is only minor retreat at the red and yellow arrow, but thinning has led to the small extension of the main icefall being almost cutoff by bedrock. By 2015 the glacier has retreated 200-300 meters from the 1989 position and the main terminus is narrower. At the yellow arrow the side valley no longer has ice. At the purple arrow this is just bedrock now, there is no glacier extension flowing down the bedrock step. A close up the icefall in a 2009 Google Earth image indicates both the extensive crevassing but also the lack of glacier ice at the purple arrow, where an extension of the icefall formerly flowed. A Google Earth closeup of the terminus indicates that only a small section is still in contact with Beaufoy Cove in 2009, with land exposed at the orange arrows. This glacier is almost not tidewater and has terminated in shallow water since 1989, which helps explain a slower rate of retreat. The glacier has thinned more rapidly than it has retreated in the last 25 years. The retreat rate is less than nearby Bertrab Glacier, Konig Glacier and Neumayer Glacier on the same coast of South Georgia.

weddel glacier 1989

Landsat Image 1989

weddell glacier 2002

Landsat image 2002

weddel glacier 2015
Landsat image 2015

weddel icefall
Google Earth icefall image
weddel terminus
Google Earth 2009 image

Lys Glacier Rapid Retreat, Italy

Lys Glacier drains south from Lyskamm in the Monta Rosa Group of Italy.  This glacier has a long history of observations that have indicated two short term advances in the 20th century 1912-21 and 1973-85 amidst a broader retreat.  The net change for the 1915-2004 interval was a 600 meter retreat (Smiraglia et al, 2006). They also noted a 10% area extent loss from 1975-2003, and since the glacier was advancing up to 1985 this change occurred more rapidly.  The Italian Glacier Commission report on terminus change of this glacier annually in the two latest reports Lys Glacier retreated 10 m in 2012 and 20 m in 2011. The total reported retreat from 2005-2012 was 186 m, more than 20 m per year. Here we examine Landsat images from 1990 to 2014.

lys ge

Google Earth Image

In 1990 two branches of the glacier merged in the valley bottom and extended to the red arrow marking the terminus of the glacier at that time.  The yellow arrow indicates the 2014 terminus position, and the yellow A indicates a prominent bedrock knob that a branch of the glacier encircles, pink arrows.  By 2013 the glacier in the main valley have separated, there are a few small lakes forming amidst the decaying stagnant ice tongue between the yellow and red arrow.  The bedrock knob at Point A has greatly expanded. In 2014 none of the termini reach the floor of the main valley.  As the stagnant ice melts, the lake area is expanding indicating that a new alpine lake will likely form.  The retreat from 1990-2014 is 1300 meters.  A closeup in 2009 from Google Earth indicates the two tongues with bedrock below separating them from the main valley floor, red arrows. There is still some relict ice below on the valley floor detached from the active glacier, blue arrows, that has small lake developing amid the stagnant ice. There is substantial crevassing above both actual termini, but not immediately. The retreat should slow now that the glacier has retreated onto steeper slopes, having lost the low elevation low slope valley tongue.
The retreat of this glacier is similar to that of nearby Verra Grande Glacier. lys glacier 1990
1990 landsat image
lys glacier 2013
2013 Landsat image
lys glacier 2014
2014 Landsat Image
lys glacier terminus
Google Earth Image

Wright Glacier Retreat, Southeast Alaska

Wright Glacier is the main glacier draining a small icefield just south of the Taku River and the larger Juneau Icefield. Wright Glacier is 60 km east of Juneau and has ended in a lake since 1948. A picture of the glacier in 1948 from the NSIDC collection indicates the terminus mainly filling the lake, but breaking up. The glacier drains the same icefield as the retreating West Speel and Speel Glacier. The dark blue arrows indicate the flow vectors of Wright Glacier, light blue arrows flow vectors for adjacent glaciers. Despite being 30 km long this glacier has been given very little attention, maybe because it does not reach tidewater.
wright glacier1948080301
NSIDC Glacier Photograph Collection Photographer unknown.

wright glacier ge
Google Earth view

In 1984 the glacier ended at a peninsula in the lake where the lake turns east. This was my view of this glacier during the summers of 1981-1984 from the Juneau Icefield with the Juneau Icefield Research Program. Our bad weather came from that direction so keeping an eye on that region during intervals between whiteout weather events, the norm, was prudent. Here we examine Landsat imagery from 1984-2013 to document the retreat of Wright Glacier and the elevation of the snowline on the glacier. The red arrow indicates the 2013 terminus, the red arrow the terminus at the time of the image and the red dots the snowline on the date of the imagery. In 1984 the lake had a length of 3.1 km extending northwest from the glacier terminus. The snowline in mid-August with a month left in the melt season was at 1150 m. By 1993 the glacier had retreated little on the north side of the lake and 200 m on the south side. The snowline in mid-September close to the end of the melt season was at 1150 m. In 1997 the fourth in a five year run of extensive mass balance losses and high equilibrium lines in the region, noted on the Juneau Icefield (Pelto et al, 2013), the snowline had risen to 1450 m. The terminus had retreated 200 m on the north side since 1984 and 600 m on the south side. In 2003 the snowline was at 1250 m with a month left in the melt season. The terminus retreat on the north side and south side since 1984 had now evened out with 900 m of retreat. In 2013 the snowline was at 1150 m in mid-August and 1350 m by the end of the melt season. The terminus had retreated 1300 m since 1984 and the lake is now 4.5 km long. The lower 2 km of the glacier has many stagnation features on it, suggesting continue retreat. It is unclear how far the basin that will be filled by the lake upon retreat extends, but it is not more than 2 km from the current terminus, as a small icefall reflecting a bedrock step occurs there. This glaciers retreat has accelerated since 1984. To be in equilibrium the glacier needs a minimum of 60% of its area to above the snowline at the end of the melt season. This is to offset the 10-12 m of melt that occurs at the terminus. This requires a snowline no higher than 1150 m. The snowline has been above this level in 1994-1998, 2003-2006 2009-2011 and in 2013, which suggest the glacier cannot maintain its current size and will continue to retreat. The glacier has a larger high elevation than the West Speel and Speel Glacier that originate from the same mountains. The glacier is following the pattern of retreat of all but one of the glaciers of the Juneau Icefield.

wright glacier 1984
1984 Landsat image

wright glacier 1993
1993 Landsat image

wright glacier 1997
1997 Landsat image

wright glacier 2003
2003 Landsat image

wright glacier 2013
2013 Landsat image

Yejyumaro Glacier Retreat Lake Expansion, Tibet, China

An unnamed glacier draining the west side of Yejyumaro Peak a Nepal-China border peak, into Tibet is referred to here as Yejyumaro Glacier. The glacier is at the headwaters of the Arun River, which crosses into Nepal at Kimathanka. A 335 MW hydropower plant is being planned for the Upper Arun River fed by this and other glaciers. The glacier is adjacent to Nobuk Glacier across the border in Nepal.nobuk tibet overview
Google Earth images from 2002 and 2013 indicate both the glacier retreat and resulting lake expansion. Red arrow is the 1989 terminus position and yellow arrow 2013 terminus position. Notice the southern and northern arms joining and turning west. Both arms of the glacier are fed by the steep border peaks with considerable avalanching.
Nobuk tibet 2002
20002 Google Earth image
Nobuk tibet 2013
2013 Google Earth image

Landsat imagery from 1989 to 2013 is used to illustrate the response of this glacier to changing climate. In 1989 the glacier extended down the unnamed lake to a peninsula, with the lake being 2.3 km long. By 2000 the glacier had retreated from the peninsula, 150-200 m retreat since 1989. By October 2013 the glacier had retreated 700 m from the 1989 position into a narrower section of the lake. The lake is now 3 km long and still growing. A December 2013 image indicates how dry this region is during the early part of the winter with only a light snowcover across the glaciated areas and higher terrain. The last image is a the Google Earth closeup indicating the transverse crevasses that are above the terminus, the crevasses narrow moving up glacier away from the terminus and disappear 400 m above the terminus. These represent the acceleration near the calving front and the indicate that calving has helped accelerate glacier flow and glacier loss. This glaciers retreat is similar to so many in the area from Nepal such as the Nobuk Glacier that is adjacent to it in Nepal, and the many Tibetan glacier retreating along the the axis of expanding lakes, Reqiang, Matsang Tsanpo and Menlung Glacier.

yejyuamro 1989
1989 Landsat image

yejyumaro 2000
2000 Landsat image

yejyumaro 2013a
2013 landsat image

yejyumaro 2013
2013 Landsat image

yejyumaro terminus
Google Earth closeup

Haworth Glacier Retreat, Selkirk Mountains, British Columbia

Haworth Glacier in the northern Selkirk Mountains of British Columbia drains into Palmer Creek, which flows into Kinbasket Lake, and then the Columbia River. This glacier is often visited by climbers as the Canadian Alpine Club has a summer base camp near the terminus of the glacier. The glacier has a low slope and limited crevassing that makes it a good training ground for climbing. Menounos et al (2008) noted an advance of this glacier overrunning a stump that has since been exposed by retreat in the period from 3800 years before present, similar in timing to many glaciers in the region. The stump remained buried until recent exposure.
haworth map
Here we examine a series of Landsat images from 1986-2013 to identify the retreat and forecast whether the glacier can survive even current climate conditions. In each image the blue dots mark the snowline, yellow arrow is the 1986 terminus and the red arrow the 2013 terminus. In 1986 the glacier ended near the far end of the basin where a lake has since developed, yellow arrow. Snowcovers 30% of the glacier in the late summer of 1986, 55-65% is necessary for glacier equilibrium. By 1994 the glacier had retreated exposing the new lake basin, the glacier was 25% snowcovered. By 1998 the glacier had retreated 550 m since 1986, the glacier was 15% snowcovered. In 2009 the glacier was 20% snowcovered. In 2013 the glacier terminates at the red arrow indicating a retreat of 1000 m since 1986, 37 m per year. The glacier is 10% snowcovered. The percent snowcover in each year is much less than the 55% minimum needed for a minimum balance, the images are also not precisely at the end of the melt season. If a glacier does not have a consistent and persistent snowcover at the end of the melt season it has no “income” and cannot survive (Pelto, 2010). This glacier has managed to retain a very small area of snowcover, but given the ongoing thinning and the lack of avalanche accumulation on this glacier, it is unlikely to be enough to save this glacier. Bolch et al (2010) noted a 10% area loss for British Columbia glaciers from 1985 to 2005, Haworth Glacier is above this average. Tennant and Menounos (2013) noted that the fastest rate of loss on Columbia Icefield glaciers from 1919-2009 was during the 2000-2009 period. The glacier is not retreating as fast as some of the glaciers that also calve into lakes such as Columbia Glacier, British Columbia. Nearby Apex Glacier has retreated at a similar rate. Jiskoot et al (2009) observed the terminus change of 176 glaciers in the Clemenceau Icefield and adjacent Chaba Icefield, and noted an average retreat of 21 meters per year from the 1980’s to 2001.
haworth galcier 1986
1986 Landsat image

haworth galcier 1994
1994 Landsat image

haworth glacier 1998
1998 Landsat image

haworth glacier 2009
2009 Landsat image

haworth glacier 2013
2013 Landsat image

Kerguelen Island Glacier Retreat Forms New Lake District

On the east side of the Cook Ice Cap on Kerguelen Island a series of outlet glaciers have retreated expanding and forming a new group of lakes, red arrow. This area is just south of Lac du Chamonix which has existed. Here we examine the changes from 2001-2014 along using Landsat imagery. This is a retreat examined by Berthier et al (2009), and exemplified by the retreat of Ampere Glacier and Aggasiz Glacier from the same ice cap. Kerguelen-Island-topo-Mapeast

In 2001 at the red arrow is the north tributary of a glacier ending in the northernmost lake at the pink arrow. In the second lake is an island, marked with point A, this glacier has a secondary terminus ending at the yellow arrow. The southernmost glacier examined at the green arrow has retreated from one lake and does not end in a lake. By 2011 the northern tributary is starting to separate losing its connection with the Cook Ice cap, red arrow and retreating from the pink arrow. The distance from the island for the middle glacier has increased. A lake is forming at the yellow arrow. For the third glacier a lake has formed at the green arrow. The 2013 Landsat image still has snowcover obscuring the glacier boundaries. In January 2014, it is evident that at the red arrow the northern tributary has lost all connection with the Cook Ice Cap. The main terminus has retreated 700 m, expanding the lake it terminates in. With the loss of the northern tributary the retreat will continue. The distance from the island at Point A to the terminus of the middle glacier has increased 900 m indicating the retreat since 2001. The glacier is nearly at the western end of the lake it terminates in. At the yellow arrow the new lake is now 900 m long indicating a retreat of slightly less than this. The green arrow marks the 2013 terminus in each image of the southern of the three glaciers. This glacier has retreated 800-900 m leading to the continued expansion of a new lake. In just a decade we see the formation of two new lakes and the expansion of two others at the terminus of the three eastern outlet glaciers of Cook Ice Cap.
lake district kerguelen 2001

lake district kerguelen 2011

lake district kerguelen 2013

lake district kerguelen 2014