Tag: Featured

Field Glacier, Alaska Retreat, Leads to Glacier Separation

On By mspeltoIn alaska glacier retreat2 Comments

Field Glacier in Landsat images from 1984, 2013 and 2017.  The red arrow indicates the 1984 terminus, the yellow arrows the 2013 terminus and the yellow dots the 2017 terminus.  The purple arrows indicate developing lateral margin lakes in 2013 and purple dots the transient snowline.

The Field Glacier flows from the northwest side of the Juneau Icefield, and is named for Alaskan glaciologist and American Geographical Society leader William O. Field. Bill also helped initiate the Juneau Icefield Research Program, which Maynard Miller then ably managed for more than 50 years. The JIRP program is still thriving today. In 1981, as a part of JIRP, I had my first experience on this glacier. It was early August and there was new snowfall everyday that week. Jabe Blumenthal, Dan Byrne and myself undertook a ski journey to examine the geology on several of the exposed ridges and peaks, note the burgundy line and X’s on image below. This was truly a remote area. The glacier begins from the high ice region above 1800 meters, there are several icefalls near the snowline at 1350 meters, and then it descends the valley ending at 100 meters. The runoff descends the Lace River into Berners Bay.This post focuses on the significant changes occurring at the front of the Field Glacier. The development of a proglacial lake at the terminus is accelerating and spreading into the main southern tributary of the glacier.  In 2013 it was observed that the lake was going to quickly expand and develop a second arm in that valley, as the two main tributaries separate.

The USGS map from 1948 imagery and the 1984 imagery indicate little change in the terminus position, with only a small lake at the terminus in 1984 with most of the margin resting on the outwash plain.  The Field Glacier by 2006 had developed a proglacial lake at the terminus that averaged 1.6 km in length, with the east side being longer. There are several small incipient lakes forming at the margin of the glacier above the main lake, each lake indicated by black and orange arrow. In 2009 the lake had expanded to 2.0 km long and was beginning to incorporate the incipient lake on the west side of the main glacier tongue. There was also a lake on the north side of this tributary. This lake was noted as being poised to soon fill the valley of the south tributary and fully merge with the main, as yet unnamed lake at the terminus, maybe this should be Field Lake.   In 2013 Google Earth imagery indicates the fragile nature of the terminus tongue that is about to further disintegrate. From 1984 to 2017 Field Glacier has experienced a retreat of 5300 m of the southern branch and 4050 m of the northern branch. This glacier is experiencing retreat and lake expansion like several other glaciers on the Juneau Icefield, Gilkey Glacier, Eagle Glacier, and Antler Glacier.

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Development of proglacial lakes from 2006 to 2009.

Terminus noted for 1984 and 2011 and the snowline in 2011.  JIRP camp locations noted by X’s.

2013 Google Earth image of the terminus. Many small icebergs already separating.

 

Aneto Glacier, Pyrenees Area Loss & 2017 Snowcover Loss

On By mspeltoIn pyrenees glacier retreat

Landsat and Sentinel 2 image from 8/24/2017 indicating the lack of retained snowcover on Aneto Glacier.  The bare glacier ice ablates faster than snow. 

Aneto Glacier in the Pyrenees of Spain is listed as its largest glacier in a 1984 inventory. In 1984 the glacier had an area of 1.32 square kilometers and a length of 1.6 km (Serrat and Ventura, 2005). The glacier is located on the northeast side of Aneto Peak. The glacier is just a few kilometers from the rapidly retreating Maladeta Glacier. From 1984 to 2016, 20 of the 39 Pyrenean glaciers  have disappeared, resulting in a loss of glacier surface area from 805 hectares in 1984 to 242 hectares in 2016, a 70% loss in 32 years (Rico et al, 2017 is in press Pireneos).  The reduction since the Little Ice Age maximum is even greater, not figure below from Eñaut Izagirre.

Aneto Glacier is a steep north facing slope glacier that receives limited avalanche accumulation.   In 2017 Aneto Glacier has suffered from an intense melt season that has seen the loss of essentially all snowcover and consequent volume/area losses from ice ablation.  This is apparent in both Landsat and Sentinel images from Aug. 24th.  At the start of August the glacier was ~50% snowcovered and by Sept. 13th a snowstorm had at least briefly covered much of the glacier with a thin blanket of snow. In 2015 and 2016 retained snowcover was also limited.  There was less snowcover in early August of 2015 than in 2017, and by the end of the month in hazy imagery the snowpack is very limited.  In early September of 2016 there is less than 10% retained snowcover.  Satellite and Google Earth imagery reveal a frequent lack of retained snowcover in the last decade.  This indicates the lack of a consistent accumulation zone, which is a necessary feature for a glacier to survive  (Pelto, 2010). This is revealed by the annual horizons exposed in the 2007 Google Earth image.  

Landsat images of Aneto glacier from 8/3/2015 and 9/6/2016 illustrating limited snowcover near the end of the summer in 2016 and with a month of peak melt in 2015 snowcover is less than 50% of the glacier. 

Rico et al (2017) figure indicating LIA area to 2016 for Maladeta and Aneto Glacier, image provided by Eñaut Izagirre @Ernatio

2007 Google Earth image of Aneto Glacier illustrating lack of retained snowcover and the many annual layers exposed by the lack of an accumulation zone.

Sentinel 2 images of Aneto Glacier area in 2017 indicating there is significant remaining snowcover on 8/4 and again by 9/13.

Sulztalferner Retreat, Austria Bedrock Expansion Mid-Glacier

On By mspeltoIn Austria Glacier retreat

Sulztalferner in Landsat images from 1990 and 2017.  Red arrow is the 1990 terminus, yellow arrow the 2017 terminus, purple dots the snowline and the green arrow an area of emergent bedrock amidst the glacier. 

Sulztalferner is a glacier in the Subaier Alps of Austria. The glacier begins at 3200 m below Daunkogel Peak and descends north from the peak.  Schlicker (2006) identified that between 1969 and 2003, 14 of the 88 glaciers in this range disappeared. The area of the glaciers was to 54.1 km2 in 1969, increased slightly to 54.4 km2 in 1985, decreased to 47.2 km2 in 1997 and the a rpaid decline to 36.9 km2 in 2003. Schlicker (2006) observed that the area of Sulztalferner, one of the largest glaciers in the region, decreased from 4.16 km2 in 1969 to 3.51 km2 in 2003. This fits the pattern of all Austrian glaciers  Fischer et al (2015).    Fischer and Kuhn (2012) measured the thickness of the glacier finding the average was 42 m and the maximum was 131 m.  The glacier terminus fluctuations are examined annually and reported by the Austrian Alpine Club  Fischer (2016) and Fischer (2017), with all 11 glacier in the Stubaier area retreating in 2015 and 2016 and Sulztalferner retreating 14 m each year.

In 1990 the glacier descended a steep icefall at the yellow arrow and terminated at 2430 m at the red arrow, the glacier was 3050 m long.  By 1999 the glacier retreat and thinning made the icefall more pronounced.  By 2015 the glacier terminated near the top of the a steep bedrock step that had caused the icefall to exist. An area of bedrock had also emerged just below the snowline. In 2017 the glacier is 2100 m long extending from an elevation of 3200 m to 2730 m.  Retreat from 1990-2017 has been 950 m, a mean of 35 m/a.  That is more than 1% of the glacier length lost per year. In 2017 in late August only 10% of the glacier has retained any snowcover indicating substantial volume losses will occur in 2017, which will drive further retreat.  This glacier is following the pattern of Bachenfallenferner just to the north. This glacier is just to the west of the Stubai Glacier and the Stubai ski area that has utilized a protective by blanket on the glacier The Stubai Glacier Ski Area opens for the 2017/18 season this Saturday 9/16 after a couple of snowstorms that have blanketed Sulztalferner and Stubai Glacier with some fresh snow.

 

Sulztalferner in Landsat images from 1990 and 2017.  Red arrow is the 1990 terminus, yellow arrow the 2017 terminus, and purple dots the snowline.

Digital Globe image from 2015 indicating the bedrock exposed in the midst of Sulztalferner.  It measures 250 m long and 150 m wide.  Note  the thin nature of the retreating terminus.

 

Sulztalferner Digital Globe image from 2015.  Note adjacent ski area and deglaciated icefall reach.

 

Bachfallenferner, Austria: 2017 Illustrates Why Glacier is Forecast to Not Survive

On By mspeltoIn Austria Glacier retreat

Comparison of Bachfallenferner (B) in Landsat images from 1990 and 2017.  The red arrow indicates the 1990 terminus position and yellow dots the 2017 terminus.  Note there is no retained snowcover in 2017 and a new lake has formed due to retreat. Other glaciers that lost all snowcover in 2017  L=Lisenser, A=Alpeiner and S=Sauischbachferner

Bachfallenferner is in the Stubaier Alpen, Austria.  The glacier terminus fluctuations are examined annually and reported by the Austrian Alpine Club  Fischer (2016) and Fischer (2017), with all 11 glacier in the Stubaier area retreating in 2015 and 2016.  Fischer and Kuhn (2012) surveyed the thickness of 64 alpine glaciers in Austria including Bachfallenferner, with a goal of determining volume.  They found in 2000 the glacier had an area of 2.08 square kilometers, with an average thickness of 41 m yielding a volume of .085 cubic kilometers.  

In 1990 Bachfallenferner ended on an outwash Plain at 2700 m.  The glacier was 2350 m long in 1990 with a width of 1100 m at its mid-point.  By 1999 a small sublacial lake has formed at the terminus, the lower 0.8 kilometer of the glacier is uncrevassed and relatively stagnant. In 1999 the snowcover the retained snowcover in late August covers 30% of the glacier.  In 2015 the glacier retreat has led to the formation of a proglacial lake that is 275 m across.  The glacier in late August is only 10-15% snowcovered.  By 2017 the glacier has retreated 400 m from its 1990 location including 60 m in 2015 and 2016.  More importantly the glacier by late August has lost all of its snowcover, as essentially have some of its neighbors: L=Lisenser, A=Alpeiner and S=Sauischbachferner.  A glacier that does not consistently retain snowcover cannot survive (Pelto, 2010). The glacier is now less than 2 km long and at the 1990 mid-point is 800 m wide.  Lateral recession in the lower 1 km of the glacier is similar to the rate of terminus recession.  The maximum ice thickness in 2000 was 97 m Fischer and Kuhn (2012), which is likely to have lost no more than a meter per year, hence there is still some comparatively thick ice.   The Stubaier Alpen has experienced substantial retreat in the last 30 years as have all Austrian Glaciers (Fischer et al.,2015).  Bachfallenferner is larger than most of the Austrian glaciers that are currently disappearing such as Mittlerer Guslarferner.

Comparison of Bachfallenferner in Landsat images from 1999 and 2015.  The red arrow indicates the 1990 terminus position and yellow dots the 2017 terminus.  Purple dots indicate snowline, not lake formed at red arrow due to glacier retreat after 1999.

Digital Globe image of Bachfallenferner in 2015. Note the lack of retained snowcover and the new lake that formed.

 

Ventisquero Grande Glacier, Chile Retreats; Not so Grande in 2017

On By mspeltoIn chile glacier retreat

Ventisquero Grande Glacier comparison in Landsat images from 1997 and 2017.  Red arrows mark the 1997 terminus, yellow arrows the 2017 terminus, purple dots the snowline and purple arrow the junction of the tributaries. 

Ventisquero Grande Glacier is at the head of Ventisquero Seno in the Cordillera Darwin of Tierra del Fuego.  The fjord is just west of Garibladi Fjord and opens into Darwin Channel.  Melkonian et al (2013) note widespread thinning of four large glaciers in the Cordillera Darwin Range from 2000-2011; Ventisquero Grande (CDI-08), Marinelli, Darwin and Roncagli, while the Garibaldi Glacier increased in volume.  Here we examine changes in the glacier using Landsat and Sentinel Images from 1997 to 2017.

In 1997 two tributaries merged 3.2 km upglacier of the terminus, purple arrow, terminating in a 1.8 km wide calving front, red arrows.  In 1999 there is limited retreat and the calving front has extended to 2 km in length.  The transient snowline is at 700 m in 1997 and at 550 m in 1999, purple dots.  By 2002 the southern end of the terminus has retreated exposing a shoal.  By 2017 the  two tributaries have separated, purple arrow.  Retreat of the glacier has been 2100 m on the north side, 2800 m in the center and 2000 m on the south side. Both of the termini are still calving and extensive crevassing immediately upglacier of the terminus indicates significant glacier velocities.  The calving front is 2.1 km wide in 2017.  As Simon Gascoin has noted the addition of Sentinel imagery has helped expand the potential for images that are relatively cloud free. Melkonian et al (2013) note velocities of less than 2 m/day until right near the terminus. The transient snowline in 2017 is at 800 m on March 28, 2017. 

Ventisquero Grande Glacier comparison in Landsat image from 1999 and Sentinel 2 image from 2017.  Red arrows mark the 1997 terminus, yellow arrows the 2017 terminus, purple dots the snowline and purple arrow the junction of the tributaries. 

Ventisquero Grande Glacier  in 2002 Landsat image. Red arrows mark the 1997 terminus, yellow arrows the 2017 terminus, purple dots the snowline and purple arrow the junction of the tributaries. 

 

Ventisquero Grande Glacier in Sentinel 2 image from 2017.  Red arrows mark the 1997 terminus, yellow arrows the 2017 terminus,  and purple arrow the junction of the tributaries. 

Blackfoot Glacier, Glacier National Park Slow Recession Indicates Persistence

On By mspeltoIn Glacier National Park

Comparison of Blackfoot Glacier in August Landsat images from 1998, 2015 and 2017

Blackfoot Glacier is the second largest glacier in Glacier National Park in Montana.  The glacier is on the north side of Mount Blackfoot and is close to two other glaciers Harrison and Jackson.  Glacier National Park over the last decade has initiated and maintained an extensive glacier monitoring program led by Dan Fagre.  This program has led to consistent mass balance observations on Sperry Glacier, repeat photography and repeat mapping.  The repeat mapping indicates the area lost from 1966 to 2015 (Fagre et al, 2017).  They identified that all glaciers lost substantial area, with Blackfoot Glacier falling into a small category of  seven glaciers that lost less than 20% of their total area in the last 50 years.  The glacier currently has an area of 1.5 square kilometers, a reduction of 18% since 1966 (USGS, 2017).  NASA (2016) provides a comparison of the glacier in 1984 and 2016. Here we examine Landsat and Google Earth imagery to better understand the slower change observed on this glacier.  The area lost to retreat on Blackfoot Glacier is similar to that on Harrison and Rainbow Glacier. 

In 1998 glacier volume losses were significant in the region, but in mid-August Blackfoot Glacier was still more than 60 % snowcovered, a significant area of accumulation.  In 2005 another year of minimum mass balance in the region the glacier had more than 60% snowcover in mid-August. In 2015 glacier volume losses in the region were again large, with Sperry Glacier having a loss of -1.22 m. Blackfoot Glacier still retained a significant area of accumulation, with more than 60% snowcover.  In 2017 the glacier is more than 90% snow covered on 8/12/2017 indicating that the glacier continues to maintain a significant accumulation zone.  This indicates the glacier is not as vulnerable to warming and will allow the glacier to continue to persist until 2050 at least. The key to retention of snowpack is high accumulation rates on the glacier, this allows snowpack to persist. Glaciers that lack a persistent accumulation zone, cannot survive current conditions (Pelto, 2010).

Blackfoot Glacier in 2005 Google Earth imagery, with margin in orange.

Blackfoot Glacier in 2015 Google Earth imagery, with 2005 margin in orange.  Note the limited retreat in this period. 

 

Saleina Glacier, Switzerland Terminus Separation

On By mspeltoIn switzerland glacier retreat

Saleina Glacier comparison in 1985 and 2015 Landsat images.  The red arrow is the 1985 terminus, the yellow arrow the 2015 terminus and the purple dots the transient snow line in these August images. 

Saleina Glacier is south of Trient Glacier descending a steep eastward oriented valley from Aiguille d’Argentiere on the northern end of the Mount Blanc Range.  The Swiss Monitoring Network has maintained annual observations of the glacier front since 1878.  After a sustained retreat during the first half of the 20th century, the glacier advanced 215 m from 1964-1988.  From 1990 to 2015 the glacier retreated 640 m. 

Here we use Landsat imagery from 1985-2017 and Google Earth images to identify ongoing changes. In 1985 the glacier extended down valley to an elevation of 1850 m, just before the valley turns east.  After 2000 the lower 800 m of the glacier became debris covered, but up to at least 2009 remained crevassed indicating activity.  By 2015 this section of the glacier no longer has crevassing or glacier ice exposed at the surface and has essentially collapsed and is no longer part of the main glacier.  This is illustrated in a comparison of Google Earth images from 2011 and 2015.  Points A,B and C represent the same bedrock locations adjacent to the glacier.  The green arrows indicate a medial moraine on active ice in 2009 and what has become an ice cored moraine ridge without adjacent active ice in 2015.  In 2009 the blue arrows indicate areas of crevassing indicating active ice.  In 2015 the purple arrows indicate buried ice cored moraine as indicated by meltwater wetting the sediments.  The total retreat of the active front from 1985 to 2015 is 1250 m, with the active front at 2300 m.  The retreat has been driven by a rise in the end of melt season snowline. This amount of retreat is similar to that of adjacent Glacier du Tour. 

In 1985 the snow line in mid-August was at 2900 m, in 2015 in late August the snowline was at 3075 m and in late August of 2017 the snowline is at 3150 m.  The summer of 2003 is when the highest snowlines were reported across the western Alps  (Rabatel et al 2013). That summer of 2003 in mid-August the snowline on Saleina Glacier was at 3050 m in an August snowline comparison of Mont Blanc glaciers. This years snowline will likely end the year as high or higher than 2003, the extensive negative mass balance will drive further retreat.

The 2016 inventory of Swiss glaciers noted several with significant retreats due to separation of stagnant ice areas and active ice.  Saleina Glacier warrants being in this category.

 

Saleina Glacier in 2017 Landsat image.  The red arrow is the 1985 terminus, the yellow arrow the 2015 terminus and the purple dots the transient snow line on 8/26/2017.

 

Points A,B and C represent the same bedrock locations adjacent to the glacier in the 2009 and 2015 Google Earth images.  The green arrows indicate a medial moraine on active ice in 2009 and an ice cored moraine ridge without adjacent active ice in 2015.  In 2009 the blue arrows indicate areas of crevassing.  In 2015 the purple arrows indicate buried ice cored moraine as indicated by meltwater wetting the sediments.

 

Yellow arrows mark the end of the active ice in 2015 on Saleina Glacier. 

 

Record High Mont Blanc, France Glacier August Snow Lines 2017

On By mspeltoIn france glacier retreat, glacier climate change

Landsat image of the transient snow line on Mont Blanc Glaciers, France on 8/19/2017.  The average snow line (Purple dots) is at 3100 m.  Glaciers on Mer de Glace (M), Argentiere (A), Tour Glacier (L), Trient Glacier (T) and Saleina Glacier (S). 

This has been a warmer summer in the Alps with reports emerging of various summer ski areas that take advantage of glaciers closing early or adding snow guns to stay open, Molltal Glacier, Les2Alpes,, Stelvio Glacier  Here we compare in Landsat images the transient snow line on five Mont Blanc glaciers from 1985, 1988, 2003, 2014, 2015 and 2017.  The transient snow line is indicated with purple dots in each image.  A comparison of the transient snow line on Mont Blanc glaciers on 8/19/2017 to other years indicates it is already higher than all other years examined, but a month remains in the melt season. 

Rabatel et al (2013)  examined the equilibrium line altitude (ELA) of glaciers in the region from 1984-2010.  The ELA is the snowline at the end of the summer melt season.  The transient snow line is simply the snow line altitude on a specific day during the melt season. Rabatel et al (2013) found the average snow line of 3000 m on Trient Glacier, 2900 m on Tour Glacier, 2800 m on Argentiere Glacier and 2975 m on Saleina Glacier.  They also observed the maximum snowline occurred in the western Alps in 2003 with an average of ~3250 m, this average is higher than for just the Mont Blanc glaciers. 

On August 11, 1985 the snow line averages 2800 m on the five glaciers.  In 1988 on Sept. 12 the snowline averages 2900 m.  On August 5, 2003 the average snow line is at 3025 m.  On Sept. 12 2014 the average snow line is at 2850 m.  On Aug. 31, 2015 the average snow line is at 3050 m.  On Aug. 19th 2017 the average snow line is at 3100 m.  This is the highest observed August snow line on Mont Blanc. With several weeks to go the snow line is competition with 2003 for the highest snow lines on Mont Blanc glaciers in the last 50 years by the end of the melt season. 

Six and Vincent (2014) noted for Argentiere Glacier that for each 1 C rise in temperature the ELA rises 50 m.  The higher snow line in 2017 indicates a year of significant negative mass balance, which will further enhance retreat of the the Mont Blanc glaciers, such as Mer de Glace and Tour Glacier. 

Landsat image of the transient snow line on Mont Blanc Glaciers, France on 8/5/2003.  The average snow line (Purple dots) is at 3000 m.  Glaciers on Mer de Glace (M), Argentiere (A), Tour Glacier (L), Trient Glacier (T) and Saleina Glacier (S).

Landsat image of the transient snow line on Mont Blanc Glaciers, France on 8/11/1985.  The average snow line (Purple dots) is at 2800 m.  Glaciers on Mer de Glace (M), Argentiere (A), Tour Glacier (L), Trient Glacier (T) and Saleina Glacier (S).

 

Landsat image of the transient snow line on Mont Blanc Glaciers, France on 9/12/1988.  The average snow line (Purple dots) is at 2900 m.  Glaciers on Mer de Glace (M), Argentiere (A), Tour Glacier (L), Trient Glacier (T) and Saleina Glacier (S). 

Landsat image of the transient snow line on Mont Blanc Glaciers, France on 9/12/2014.  The average snow line (Purple dots) is at 2850 m.  Glaciers on Mer de Glace (M), Argentiere (A), Tour Glacier (L), Trient Glacier (T) and Saleina Glacier (S). 

Landsat image of the transient snow line on Mont Blanc Glaciers, France on 8/31/2015.  The average snow line (Purple dots) is at 3050 m.  Glaciers on Mer de Glace (M), Argentiere (A), Tour Glacier (L), Trient Glacier (T) and Saleina Glacier (S). 

Observing Glacier Runoff Changes Under the Same Weather Conditions

On By mspeltoIn glaciers salmon, North Cascade Glaciers


View of Sholes Glacier on August 8th in 2015 left and 2017 right.  Note difference in ratio of snow surface to ice surface exposed. 

Sholes Glacier is at the headwaters of Wells Creek in North Fork Nooksack River watershed in Washington.  We have been measuring the mass balance of this glacier annually since 1990 and runoff in detail since 2012 (Pelto, 2015).  Glacier runoff in this watershed during late summer frequently provides more than a third of all runoff for the watershed, this occurred on 37 days in 2015 and 19 days in 2016.  This water is critical for local hydropower, irrigation and fall salmon runs. We measure glacier runoff all summer long directly at a stream gage 150 m from the glacier.  We also measure ablation directly on the glacier.  The amount of runoff is dependent on the area exposed for melting, glacier area in this case, the melt rate which is largely determined by temperature and the surface type, snow and ice having different melt rates.

A typically reliable method to calculate glacier runoff is a degree day model.  This model is based solely on daily observed temperature and the glacier surface type. The degree day melt rate factor for snow and for ice are different.  Based on 27 years of ablation measurements on the glacier the melt factors for snow is 0.0045 m w.e. d-1C-1 and for ice 0.0060 m w.e. d-1C-1  which falls within the range of temperate glacier observations (Hock, 2003).  If you multiply this result by the area of the glacier the glacier runoff is determined. 

 

For a specific day the determination of runoff looks like:

Glacier Runoff=( 14 C * 0.0045 m w.e. d-1C-1)(550,000 m2) + (14C*0.0060 m w.e. d-1C-1)(100,000m2)

This equals 43,000 m3 for the day or 0.5 m3/second from Sholes Glacier.  In fact our measurement of discharge on this day was 41,330 m3 and the observed melt rate was within 5% of the calculated amount.  In August the average streamflow in the North Fork Nooksack at the USGS gage is 22 m3/second.  We have observed that ablation rates on Sholes Glacier are consistent with those on other glaciers in the watershed.  For the watershed as a whole the glacier runoff on this particular day would be 9.4 m3/second or ~40% of mean daily August runoff provided by glacier melt. 

It has been interesting in the case of the Sholes Glacier to observe how different the runoff rate/volume is for the same weather conditions depending solely on changes in snow and ice cover area.  Note in the images above from 2015 and 2016 the change in the percent of the glacier that is snowcovered.  Also note the difference below from 2014 and 2017.  Given the same weather conditions the melt rate formula suggest that ice covered areas will yield 33% more runoff.  This in fact has been the case with observed runoff on a 14 C day in 2015 yielding 30% more runoff than on the a 14 C day in 2017.  The difference is no ice exposed in 2017 and 85% of the glacier area being bare ice on the observed day in 2015.  The change during a melt season as indicated by snowcover change in 2016 from August 16th to Sept. 8th, illustrates the importance of understanding the changing distribution of snow and ice on the glacier on a weekly basis for determining glacier runoff. 

On 8/8/2014 the glacier was 85% snowcovered

On 8/8/2015 the glacier was 15% snowcovered

On 8/8/2016 the glacier was 97% snowcovered

On 8/8/2017 the glacier was 100% snowcovered

View of Sholes Glacier on August 8th in 2014 left and 2016 right.  Note difference in ratio of snow surface to ice surface exposed. 

Jill Pelto and Andrew Hollyday measuring flow below Sholes Glacier.

Pete Durr Probing snowpack on Sholes Glacier

Sholes Glacier August, 16 2016
Sholes Glacier Sept., 8 2016

34th Annual Field Program NORTH CASCADE GLACIER CLIMATE PROJECT 2017

On By mspeltoIn North Cascade Glaciers

 

2016 Field Season Video

NORTH CASCADE GLACIER CLIMATE PROJECT 2017

For the thirty fourth consecutive summer it is time to head into the field to monitor the continued response of North Cascade glaciers to climate change.  In 1984 when I began this program we selected 10 key glaciers to monitor.  Two of these have now disappeared.  All the glaciers have retreated extensively and lost considerable volume.  The mass balance loss is 19 m of water equivalent thickness, which is over 20 m of ice thickness loss on glaciers that averaged less than 75 m thick. This is significant with 25-30% of their entire volume lost. This project looks at the implications of the glacier loss as we complete an annual inventory of ice worms on Sholes Glacier, mountain goats on Ptarmigan Ridge region and monitor runoff all summer below Sholes Glacier with the Nooksack Indian tribe. 

Illustration of research (Megan Pelto and Jill Pelto)

The result of volume loss and area loss is that despite higher melt rates, the reduction in area of melting glaciers has led to a decline in glacier runoff in the region. The reduced runoff effects salmon, hydropower and irrigation. Details of the runoff impacts are detailed in a Book “Climate Driven Retreat of Mount Baker Glaciers and Glacier Runoff and summarized in Salmon Challenges from the Glaciers to the Salish Sea.

The focus will be on mass balance observations, longitudinal profiles and terminus observations. For Mount Baker, Washington the winter freezing level was much lower than the previous two winters, and was 100 m below the long term mean. The snowpack on April 1st snowpack was 110% of normal, by June 10th, the snowpack is trending down steeply, but remained just above average.  Since then a persistent dry period and the impending heat wave that begins today, Aug. 1 has led to rapid snow loss.  The most recent  comparable year is 2009, which featured a good winter snowpack and very warm mid to late summer conditions. We will first travel north to Mount Baker and the Easton Glacier.    Of the 40 glacier in the World Glacier Monitoring Service Reference glacier list we have two Columbia and Rainbow, as soon as Easton Glacier has 30 years, the minimum requirement it will be added, that is in 2019. The field team consists of Mauri Pelto, 34th year, Jill Pelto, UMaine for the 9th year, Anthony Himmelberger, Clark University 1st year.  Tom Hammond, 14th year will join us for a selected period as will Pete Durr, Mt. Baker Ski Area, 2nd year.   We will report on our findings in a month. Field photos will be posted periodically on Twitter.

Measuring terminus change and snowpack thickness in 2016

Aug.   2:  Hike into Easton Glacier
Aug.   3:  Easton Glacier
Aug.   4:  Easton Glacier
Aug.   5:  Hike Out Easton Glacier, Hike in Ptarmigan Ridge
Aug.   6:  Sholes Glacier
Aug.   7:  Rainbow Glacier
Aug.   8:  Sholes Glacier
Aug.   9:  Hike out and into Lower Curtis Glacier
Aug. 10:  Lower Curtis Glacier
Aug. 11: Hike out Lower Curtis Glacier- Hike in Blanca Lake
Aug. 12:  Columbia Glacier
Aug. 13:  Columbia Glacier
Aug. 14:  Hike out Columbia Glacier; Hike in Mount Daniels
Aug. 15:  Ice Worm Glacier
Aug. 16:  Daniels and Lynch Glacier
Aug. 17:  Ice Worm Glacier, Hike out Mount Daniels-Hike out-

Plaine Morte Glacier, Switzerland July 2017 Bare of Snow

On By mspeltoIn switzerland glacier retreat

Landsat images from 2013, 2014 and 2015 and Sentinel Image from 2017 indicating lack of snowcover on Plaine Morte Glacier (PM).  Nearby Wildstrubel Glacier (W) terminus has separated since 2005.

Glacier de la Plaine Morte  (Plaine Morte: PM) is in the Swiss Alps just north of Crans Montana.  The Crans Montana resort has a lift that ends just above the glacier, and a ski loop traverses the middle of the glacier (see map below).  The glacier has a limited elevation range from 2900-2500 m.  It has a low slope 4 degree or less over the main plateau area of 5 square kilometers between 2650 m and 2800 m.  Huss et al (2013) observed the glacier lost an average of 35 m in thickness from 1954-2011, this represents a greater mass loss than the regional average of 22 m. At the southeast margin of the glacier is Lac des Faverges, that forms and drains each summer which Huss et al (2013)  expect to expand substantially with further retreat and downwasting.  The glacier is just east of Wildstrubel Glacier (W)

What is clear from examining Landsat imagery is that the glacier does not retain substantial areas of snowcover most years.  This means the glacier lacks a consistent accumulation zone and cannot survive (Pelto, 2010).  The warm summer of 2017 has left the glacier without snowcover even though it is only mid-July.  The mass balance loss this year will be substantially over 1 m this year. This has been the case in 2013, 2014 and 2015 as well by the end of August.  The loss of of snowcover is also observed in Landsat images from 2003, 2004 and 2005.  The 2009 image is from Google Earth, Lac des Faverges has not drained yet (F) and the glacier is yet again lacking snowcover.  The glacier is larger than the soon to disappear Cavagnoli and loses its snowpack more often than Basodino.  The glacier cannot survive, but is still large and will not disappear quickly. There is clearly a concentric basin to the right (east) of the PM in the glacier center. Wildstrubel Glacier in 2004 and 2005 terminated beyond the convergence of two glacier tongues, yellow arrow.  In 2015 and 2017 it is evident that retreat has led to a separation of the glaciers. 

Landsat images from 2004,  and 2005 indicating lack of snowpack on Plaine Morte Glacier (PM).  Nearby Wildstrubel Glacier (W) terminus is joined in 2005.

Google Earth image from 2009 of glacier, with Lac Faverges evident (F).

Ski trail map of Crans Montana

Ellsworth Glacier Retreat & Lake Expansion, Alaska

On By mspeltoIn alaska glacier retreat

Ellsworth Glacier in 1989 and 2016 Landsat images.  Upper yellow arrow marks the west terminus in 2016 and the lower yellow the 2016 east margin.  Purple dots mark the snowline and purple arrows tributaries from the east that are thinning and disconnecting.  Orange arrow marks icebergs in the lake. 

Ellsworth Glacier is a valley glacier draining south from Sargent Icefield on the Kenai Peninsula in Alaska. Along with the Excelsior Glacier it has been the longest glacier of the icefield.  The glacier retreated into an expanding proglacial lake in the early 20th century (USGS-Molnia, 2008). The terminus in 2000 was reported to be  3.5 to 4.5 km from the 1908 position (USGS-Molnia, 2008).  Here we examine Landsat images to document changes from 1989 to 2016. 

In 1989 the snowline was at 925 m, purple dots, a tributary from the east joined just above the terminus, lower yellow arrow.  The terminus had a small embayment on the west side.  In 2001 the snowline was at 875 m, with little evident change in the terminus position.  By 2015 the tributary from the east has detached from the main glacier, the snowline is at 1000 m.  The lake has expanded considerably along the western margin and the tongue of the glacier has narrowed in the lower 2 km.  In 2016 the snowline is at 975 m, the lake has now extended 3 km along the western edge.  This rapid lake expansion indicates that the lower 3 km of the glacier occupies a basin that will become a lake and that the tongue is partially afloat and given the narrowing thinning tongue is poised for collapse, see below.  The number of icebergs in 2016 indicates that significant ice calved during that year. The retreat of the eastern margin has been 500 m, with a 3.4 km retreat on the west side.  The main tongue in the lower two kilometers is 800 m wide versus 1200 m wide in 1989.  It is also worth noting the greening of the elongated nuntak in the middle of the glacier several kilometers above terminus.  Along with the rapid 3.5 km retreat of the adjacent Excelsior Glacier, leaves the longest glacier from the icefield up for grabs. 

Ellsworth Glacier in 2001 and 2015 Landsat images.  Upper yellow arrow marks the west terminus in 2016 and the lower yellow the 2016 east margin.  Purple dots mark the snowline and purple arrows mark tributaries from the east that are thinning and disconnecting. 

Ellsworth Glacier in2016 Landsat image.  Upper yellow arrow marks the west terminus in 2016 and the lower yellow the 2016 east margin.  Purple arrows mark tributaries from the east that are thinning and disconnecting.  Orange arrow marks icebergs in the lake.