Carbon Lake Glacier Retreat, Alaska

On Baranof Island in southeast Alaska there are a pair of unnamed glaciers at the headwaters of the Carbon Lake watershed, that then drains into Chatham Strait.  Here we examine changes in these glacier from 1986 to 2014 using Landsat imagery.  The blue arrow indicates the northern glacier terminus and the yellow arrow the southern glacier terminus region.

carbon lake ge

In 1986 the southern glacier terminus, yellow arrow consisted of three main tributaries combining to form a low sloped terminus region.  The northern glacier had a single terminus.  By 1997 a lake has formed at the southern glacier, which now has two separate termini, the red arrow indicates a new terminus area and the pink arrow the eastern portion of this glacier.  The northern glacier, blue arrow, is retreating but still joined.  By 2014 the southern glacier has separated into three parts.  There is a terminus at the red arrow, this represents a 900 m retreat since 1986.  This portion of the glacier has further separated since 1997 into two parts.  The eastern glacier, pink arrow has retreated 700 m since 1986.  The new alpine lake is 600 m long.  The northern glacier, blue arrow, has separated into two main termini and the glacier has retreated 200 m.   The retreat of these glaciers paralells the observed losses of other smaller glacier in the region most notably Lemon Creek Glacier, which is a World Glacier Monitoring Service reference glacier, 30 km west on the edge of the Juneau Icefield.  Another nearby example is 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.

carbon lake 1986

1986 Landsat image Carbon Lake Glaciers

carbon lake 1997

1997 Landsat image Carbon Lake Glaciers

carbon lake 2014

2014 Landsat image of Carbon Glacier

 

 

Nizina Glacier Retreat, Lake Formation, Alaska

If you have heard of Nizina Glacier in the Wrangell Mountains of Alaska it is probably because you have contemplated a float trip down the Nizina River from Nizina Lake.  In 1990 there was no lake, since 2000 the lake has provided a good location for float planes to land.  In 2014 the lake has reached a new maximum in size and minimum in icebergs on its surface.  Here we examine Landsat imagery form 1990-2014 to identify changes in the Nizina Glacier.  The main tributary of the Nizina Glacier is Regal Glacier indicated by the dark blue flow arrows.  The light blue flow arrows are from the Rohn Glacier tributary that no longer reaches the terminus area.

nizina ge

Google Earth image

In each image the yellow arrow marks the 1990 terminus, red arrow the 2014 terminus location and pink arrows the summer snowline.  In 1990 the glacier had narrow sections of fringing lake evident, though the glacier reached the southern shore of the developing lake at yellow arrow.  By 1995 the lake had developed to a width of 100-300 m fringing the shoreline around the terminus of Nizina Glacier.  In 1999 the main lake has developed and is 1.6 km long and 1.3 km wide though it is still largely filled with icebergs.  In 2013 there are a few icebergs left in the lake.  In August, 2014 the lake is free of icebergs for the first time, which does mean more will not form. The lake is 1.4 km wide and 2.3 km long.  The glacier has retreated 2.1 km from 1990 to 2014, a rate of 150 m per year, red arrow marks 2014 terminus. A close up view of the terminus in Google Earth from 2012 indicates numerous icebergs but also substantial rifts, green arrows, that will lead to further iceberg production and retreat.  The snowline in this late July or early August images is typically at 1800-1900 m, pink arrow, with a month still left in the melt season. The retreat of this glacier is similar to that of glaciers in the Talkeetna Range to the west South Sheep Glacier and Sovereign Glacier and Valdez Glacier to the south.

nizina glacier 1990

1990 Landsat image

 

nizina glacier 1995

nizina glacier 19991995 Landsat image

nizina glacier 1999

1999 Landsat image

nizina glacier 2013

2013 Landsat image

nizina glacier 2014

2014 Landsat image

nizina lake 2012

Google Earth image 2012

 

Davidson Glacier Retreat, Alaska

Davidson Glacier is a large glacier that flows east from the Chilkat Range to the foreland along Chilkat Inlet and Lynn Canal in southeast Alaska. As a result it has a long history of observation of change. Molnia (2008) noted that from 1889 to 1946 the glacier retreated 400 m and a lake had developed at the terminus. By 1978 the glacier had retreated another 700 m with the proglacial lake at the terminus further expanding. Molnia (2008) futher observed a 700 m retreat by 2004. Here we examine Landsat imagery from 1993 to 2014 to identify recent changes of the glacier.

davidson map
USGS map

davidson ge
Google Earth Image

In 1984 the glacier terminated at the end of a peninsula extending from the south side of the proglacial lake, red arrow. The purple arrow is the snowline at 1100 m. The orange arrows indicate two tributaries feeding the main glacier. By 2001 the terminus has retreated 500 m into a narrower western section of the lake. In 2004 the snowline is at 1250 m, leaving little accumulation area. In 2009 the snowline is at 1200 m. The terminus has retreated from the proglacial lake. In 2013 the snowline is at 1100 m, there is a river connecting the terminus at the yellow arrow to the proglacial lake. The glacier no longer reaches the foreland having retreated into a mountain valley. In 2014 the snowline was at 1300 m at the start of August with a month left in the melt season. The two tributaries at the orange arrows only have a thin connection to the main glacier. The terminus has retreated 800 meters from 1984 to 2014. The retreat will continue due to the high snowlines in recent years and tributary separation. The retreat is less than most nearby glaciers such as Sinclair Glacier or Ferebee Glacier, just east across Lynn Canal.

Johnson et al (2013) compare changes in Davidson and Casement Glaciers that share a flow divide at 1200 m, Casement Glacier flows west and Davidson Glacier flows east. Both glaciers thinned at a rate of 1 m per year at the flow divide from 1995-2011. This is an indication of the high snowlines and negative glacier mass balance. Casement Glacier had a much greater thinning below 600m than Davidson Glacier, which leads to greater retreat. The difference is that Davidson Glacier has a steeper gradient from the terminus than most glaciers. davidson 1984
1984 Landsat image
davidson 2001
2001 Landsat image
davidson 2004
2004 Landsat image
daidson 2009
2009 Landsat image
davidson 2013
2013 Landsat image
davidson 2014
2014 Landsat image

Sinclair Glacier Retreat, Alaska

Sinclair Mountain is on the east side of the Lynn Canal in southeast Alaska. The mountains hosts too substantial glacier, the south flowing unnamed glacier is referred to here as Sinclair Glacier. This glacier terminated in a lake in the 1982 map of the Skagway region. I observed this glacier from the air in 1982 and it was ending in this lake. Here we examine Landsat imagery from 1984 to 2014 to identify changes. sinclair map
USGS Skagway map
Sinclair ge
Google Earth Image

In 1984 the glacier ended at a prominent peninsula in the lake, red arrow in each image, the lake was 1700 m long. The snowline was at 950 m, indicated by the purple arrow, this was at the end of the melt season. The glacier was joined by two tributaries from the west side, orange arrows. In 1986 there is a small amount of terminus retreat visible. By 2001 the glacier has retreated out of the lake, which is 2.9 km long. By 2004 the southern tributary at the orange arrow is no longer connected to the glacier. The glacier has retreated 1.3 km from 1984-2004. The snowline is at 950 m with a month left in the melt season. In 2009 the image is not great quality, but the northern tributary is still connected to the main glacier by a thin tongue of ice at an icefall at 850 m. By 2013 the northern tributary is no longer connected to the main glacier, there is bare rock extending across the full width of the former icefall area. In 2014 the image is from the end of July and the snowline is already above 950 m. It is evident that the glacier will lose nearly all of its snowcover by the end of the melt season on October 10th. The glacier has retreated 900 meters since 2004, and 2.2 km since 1984. The recent loss of tributaries indicates less contribution of ice to the glacier and that retreat will continue. This retreat is the same as that of nearby Field Glacier, Meade Glacier and Ferebee Glacier.
sinclair 1984

1984 Landsat image
sinclair 1986
1986 Landsat image
sinclair 2001
2001 Landsat image
sinclair 2004
2004 Landsat image
sinclair 2009
2009 Landsat image
sinclair 2013
2013 Landsat image
sinclair 2014
2014 Landsat image

Sovereign Glacier Retreat, Talkeetna Mountains, Alaska

Sovereign Glacier is on the northeast side of the Talkeetna Mountains, Alaska and drains into the Talkeetna River. The Sovereign Glacier, red arrow, was joined by a tributary from the south in the map image, pink arrow. Molnia (2007) noted that all glaciers in the region have retreated since the early 1950’s when the area was mapped and that all the major termini were retreating and thinning in 2000. Here we examine Landsat imagery from 1986 to 2014.
talkeetna_mountains-1983
In 1986 the glacier terminates at the red arrow at the valley junction. The tributary to the south, pink arrow has separated from the main glacier and ends in a proglacial lake. In 1989 retreat is evident during the last three years with an expanding proglacial lake at the pink arrow, and the glacier terminus no longer reaching the valley junction, red arrow. By 2001 the glacier has retreated most of the distance from the red arrow at the 1986 terminus location to the yellow arrow, the 2014 terminus location. The former tributary glacier has receded from the proglacial lake. In 2009 there are two new outcrops of bedrock in the upper portion of the glacier indicating glacier thinning near the equilibrium line at 2000 m, at green arrow. By 2014 the main glacier has retreated 1100 m from the 1986 position, red arrow, to the yellow arrow. The tributary glacier at the pink arrow has retreated 400 m since 1986. The green arrow indicates further thinning of the upper glacier since 2009. The thinning upglacier indicates that retreat will continue. The retreat parallels that of nearby South Sheep River Glacier. This thinning in the upper glacier is similar to that of Lemon Creek Glacier as well (Pelto et al, 2013).
sovereign Glacier 1986
1986 Landsat image
sovereign Glacier 1989
1989 Landsat image

sovereign Glacier 2001
2001 Landsat image

sovereign Glacier 2009
2009 Landsat image

sovereign Glacier 2014
2014 Landsat image

South Sheep River Glacier Retreat, Alaska

South Sheep River Glacier is the informal name of the longest glacier in the Talkeetna Mountains of Alaska. This glacier is the headwaters of the Sheep River and is comprised of two major glacier branches from the east and west meeting and turning north down the Sheep River valley. Molnia (2007) noted that all glaciers in the region have retreated since the early 1950’s when the area was mapped. Molnia (2007) noted that all the major termini were retreating and thinning in 2000. Here we examine Landsat imagery from 1986 to 2014. In the early 1950’s the glacier extended 5.5 km north down the Sheep River Valley from the main glacier junction, red arrow.
sheep river glacier map
USGS Map
In each image the red arrow indicates the early 1950 terminus position, the yellow arrow the 1986 terminus and the pink arrow the 2014 terminus position. In 1986 the glacier had retreated 2.5 km from the 1950’s position. The terminus is at the mouth of the first significant glacier valley draining into the Sheep River from the west. The medial moraine extending to the terminus from the glacier junction is quite prominent. There is a small tributary at Point A that joins the eastern branch of the glacier. In 1989 the snowline on the glacier is at 1700 m. By 2001 the glacier has retreated substantially from the yellow arrow and side valley from the west. In 2009 the snowline is quite high at 2000 m. Th eastern tributary is quite thin beyond the junction, and adds little ice to the now short northward flowing segment. The late Sept. 2014 Landsat image is after a fall snowstorm and the snowline has lowered. The terminus is now at the pink arrow a 4.5 km retreat since the early 1950’s. The glacier has retreated 2 kilometers since 1986. The tributary at Point A now terminates 600 meters from the eastern branch. The glacier flows just 1 km north from the main junction versus 5.5 km in 1950. The terminus remains thin, and the narrow eastern tributary appears ready to separate from the west flowing tributary. This is not an imminent change, but is inevitable. The retreat is the same as that of nearby Sovereign Glacier and glaciers to the south, Pedersen Glacier and Fourpeaked Glacier
sheep river glacier 1986
1986 Landsat image

sheep river glacier 1989
1989 Landsat image

sheep river glacier 2001
2001 Landsat image

sheep river glacier 2009
2009 Landsat image

sheep river glacier 2014
2014 Landsat image

Ferebee Glacier Rapid Retreat, Alaska 1986-2014

Ferebee Glacier is in the Coast Range of Alaska 15 km northeast of Skagway. The Ferebee River that drains the glacier flows into the Chilkoot Inlet. The glacier begins at 1800 m in the Klukwah Mountains and flowed south and terminated on an outwash plain at 200 m in the USGS map of the region from 1955. Little change in the terminus occurred prior to 1981. I observed the glacier from the air in 1981 and there was no lake at the terminus and only a minor several hundred meter wide devegatated zone from recent retreat. Here we examine Landsat imagery from 1986-2014 to identify recent change. A landslide occurred onto Ferebee Glacier in 2014, that will add debris cover to the surface that is limited today.
ferebee glacier ge
Google Earth image

ferebee map
USGS map of area

In each image the red arrow marks the 1986 terminus, the yellow arrow the 2014 terminus and the purple dots the snowline. In 1986 the glacier still terminated on the outwash plain at the south end of what is a newly forming lake small pockets of open water are evident on the lateral margins. The snowline is at the base of the lower icefall at 900 m. By 1999 a lake has formed at the terminus, that is 1.2 km long, a retreat of nearly 100 meters per year. The snowline is at 1000 m in 1999. A 2004 Google Earth image of the terminus area indicates two regions of concentric crevassing upglacier of the terminus, one adjacent to the yellow arrow, this indicates ice that has been lifted and then dropped by water, which only happens if the ice is thin enough for flotation. By 2013 the lake has more than doubled in length and the snowline is near the top of a pair of icefalls at 1300 m. In 2014 the lake is 2.7 km long on the eastern shore and 2.5 km long on the western shore. The glacier has retreated 2.6 km in 28 years, still nearly 100 m/year. The lake is not becoming narrower and there is no elevation step on the glacier, to suggest the end of the developing lake is near. The snowline in 2014 even in early August is at 1400 m. This glacier will continue to retreat as long as the snowline is above the top of the icefalls at 1250 m. The retreat of this glacier is like the Meade Glacier across Chilkoot Inlet, LeBlondeau Glacier just to the west and Gilkey Glacier to the south.
ferebee glacier 1986
1986 Landsat image

ferebee glacier 1999
1999 Landsat image

ferebee ge terminus
2004 Google Earth image

ferebee glacier 2013a
2013 Landsat image

ferebee glacier 2014
2014 Landsat image

Meade Glacier Rapid Retreat 1986-2014, Alaska

Meade Glacier drains the northwest portion of the Juneau Icefield, with meltwater entering the Katzehin River and then Chilkoot Inlet. The glacier begins in British Columbia and ends in Alaska. Here we use Landsat imagery to examine changes in the glacier from 1984 to 2014. The glacier experienced a slow continuous retreat from 1948 to 1986 of 400 m, the glacier ended on an outwash plain. From 1991-2006 JAXA’s EROC program noted a retreat of 570 m, retreating into a lake basin. In 2007 the lower 2.5 km of the glacier was stagnant and heavily crevasses, poised for collapse in a developing proglacial lake. The 1948 map of the glacier indicates no proglacial lake with the glacier terminating on an outwash plain.
meade map
USGS Topographic map from 1948 aerial photographs

In 1986 the terminus is indicated by an orange arrow, the 2014 terminus by a red arrow, two tributaries that connect to the Meade Glacier are indicated by yellow arrows and the snowline at is indicated by purple dots. The snowline is at 1250 m in 1986, there is no evident lake at the terminus of glacier just an expanding outwash plain. Both tributaries are 750 m+ wide where they join Meade Glacier. By 2004 a 400 m long proglacial lake has formed at the terminus. The two tributaries from the south at the yellow arrows no longer are connected to the glacier. The snowline is at 1450-1500 m, which is much higher than in 2004 on Taku Glacier or Brady Glacier. In 2009 the snowline is at 1400 m, the proglacial lake has expanded to 600 m in length. In 2014 the proglacial lake is 3.5 km long, the entire lower 2.5 km of the glacier has collapsed since 2007. There is still considerable relict ice floating in the lake. There is a substantial lake along the southern margin of the glacier where a tributary streams enters the main valley. This indicates the glacier will quickly retreat to this point by further collapse into the lake. The snowline in 2013 and 2014 was quite high and the summer’s quite warm which aided in the lake expansion. The snowline in 2014 is at 1400 m on Aug. 2, the date of the imagery, the high snowlines ensure continued mass loss and glacier retreat. There was still six week of summer melting remaining on the date of the imagery. The Meade Glacier is poised to continue a rapid retreat in the near future its retreat parallels that of most Juneau Icefield glaciers including the next glaciers to the south Field Glacier and Gilkey Glacier.

meade glacier 1986
1986 Landsat image
meade 2004
2004 Landsat image
meade glacier 2009
2009 Landsat image

meade glacier 2014
2014 Landsat Image

Spotted Glacier Retreat, Katmai Region, Alaska

Spotted Glacier flows north from Mount Douglas and terminates in a developing proglacial lake. In the USGS map from 1951 the lake is not evident. Giffen et al (2008) noted that the glacier retreated ~1200 m from 1951-1986, a rate of 33 m/year.
spotted glacier map
Here we examine 1985 to 2013 Landsat imagery to identify the terminus change of this glacier since 1985. In each image the red arrow indicates the 2013 east side of the terminus, the pink arrow a rock knob adjacent to the 1985 terminus, and the yellow arrow a peninsula that should become an island as the further retreat occurs. In 1985 there is no evidence of the peninsula, the lake is relatively round, and has a north-south length of 1250 m. By 2000 the glacier has retreated sufficiently to expose the peninsula at the yellow arrow. The lake is now 1450 m from north to south. Neither of the images indicates many icebergs suggesting this is currently not a main mechanism of ice loss. By 2013 the peninsula is 450 m long, the north-south length of the lake is 1700 m. The retreat of 450 m in the 28 year period is nearly 30 m/year, a similar rate to the 1951-2000 period. The 2012 Google Earth image indicates a few small icebergs in the lake, again suggesting that despite some calving this is not a main glacier volume loss. The glacier front remains active and crevassed, suggesting that retreat will remain slower than for nearby Fourpeaked, Excelsior or Bear Glacier.
spotted glacier 1985
1985 Landsat image

spotted glacier 2000
2000 Landsat image

spotted glacier 2013
2013 Landsat image

spotted glacier ge 2012
2012 Google Earth image

Fourpeaked Glacier Retreat, Katmai area, Alaska

Fourpeaked Glacier drains east from the volcano of the same name in the Katmai region of southern Alaksa. The Park Service in a report (Giffen et al 2008) noted that the glacier retreated 3.4 km across a broad proglacial lake that the glacier terminates in from 1951-2986, a rate of 95 m/year. From 1986-2000 they noted a retreat of 163 m, or 13 m/year. In a more recent report with the Park Service Arendt and Larsen (2012) provide a map of the change in glacier extent from 1956-2009, Figure 4, but note the poor data overall on historic changes of Fourpeaked. Here we utilize Landsat imagery to examine retreat from 1981 to July 2014.
fourpeaked ge
Google Earth image
A Landsat 2 image from 1981 with relatively low resolution indicates much of the proglacial lake still occupied by ice, but much of this is floating icebergs detached from glacier, which is hard to distinguish in this image. In each image the red arrow is the 1985 terminus and the yellow arrow is 2013-2014 terminus. In 1985 the terminus is at the red arrow, with considerable floating ice still evident that is not part of the glacier. The snowline, purple dots, is at 750-800 m though this is not near the end of the summer. By 2000 the floating ice is gone, and the terminus has retreated into a narrower inlet. The snowline is at 850 m. By 2013 the glacier has receded further up this inlet and the width of the lower glacier is less. This is a July image and the snowline is still relatively low. In the July 2014 image the snowline is quite high at 700 m, given that this is mid-summer. It is not apparent in the Landsat image, but the large local forest fires in the spring could reduce albedo and enhance melt this summer. The terminus has retreated 1.9 km from 1986 to 2014 a rate of 68 m/year. The retreat from 1981-2000 was fed by calving in a broad proglacial lake. From 2000-2014 the retreat has continued despite the narrowing of the calving front. That the glacier has narrowed even more and thinned in the lower reach is indicative of a retreat that will continue. This glacier is behaving like other Katmai area glaciers, Giffen et al (2008) noted that 19 of 20 are retreating. The glacier retreat has led to formation and expansion of a large lake much like other glaciers in the region; Bear Glacier, Excelsior Glacier and Pedersen Glacier. The last image is an animated gif created by Espen Olsen illustrating the change in the glacier. Katmai 1981
1981 Landsat image

katmai 1985
1985 Landsat image

katmai 2000
2000 Landsat image

katmai 2013
2013 Landsat image

katmai 2014
2014 Landsat image

mauri
Espen Olsen animated gif of Landsat images

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

Long Peak Glacier, Southeast Alaska

“Long Peak” Glacier is an unnamed glacier southeast of Juneau, Alaska. The glacier occupies a narrow northeast oriented avalanche fed valley, light blue arrows indicate the avalanche feeding regions around the glacier. In 1948, as indicated in the USGS map,the glacier extended from 1600 m to 500 m, a small lake is shown at the terminus, with an overall length of 3.8 km. The glacier is a short distance southwest of the retreating Speel Glacier, and it does drain into the Speel River. Here we examine Landsat imagery of changes in this glacier from 1984 to 2013. This is a small, remote glacier that receives that has not attracted attention. It is close to the Long Lake Snotel snowpack measurement station operated by the USDA. I observed the glacier in 1998 from a helicopter and thought it did not look poised to survive our warming climate for long. long peak glacier
Here we examine Landsat imagery from 1984-2013 to observe glacier retreat and lake expansion. By 1984 the lake had expanded to 750 m in length, with a glacier retreat of 500 m from the mapped terminus. The snowline is marked with purple dots, the 2013 terminus with a red arrow, and the orange arrow indicates a debris covered region of the glacier. Only 20% of the glacier is snowcovered and the melt season is not yet over in the 1984 image. This same pattern of snowcover remaining is seen in 1993, 1995, 1996, 1997 and 1998 for example. By 1999 the glacier has retreated an additional 300-350 m, the snowcovered area is greater but this is an August image. In 2013 a late June and a Late July image depict the loss of snowcover during a month. The overall length of the glacier is now 2.6 km, indicating a retreat of 1200 m since and a retreat of 700 m from 1984-2013. The glacier is still terminating in the lake that has expanded by the same amount. This glacier has not only retreated but also thinned and the slopes above the glacier have greened a bit particularly on the north side. This glacier cannot survive with the level of retained snowcover it has (Pelto, 2010). Ongoing mass balance work on the Lemon Creek Glacier of the Juneau Icefield, where the Juneau Icefield Research Program is beginning measurements next week, has thinned by 29 m during the 1955-2013 period (Pelto et al, 2013). In 2014 the Long Lake Snotel site at an elevation of 850 feet, lost its snowpack on June 11, a bit earlier than normal, indicating this glacier will lose most of its snowpack in 2014.

long peak 1984
1984 Landsat image

long peak 1997
1997 Landsat image

long peak 1999
1999 Landsat image

long peak june 2013June 2013 Landsat image

long peak 2013
July 2013 Landsat image