Tag: Featured

Winter Season Ablation in 2018 Mount Everest Region, Himalaya

On By mspeltoIn Himalaya glacier retreat

Landsat images from Nov. 17 2017 and Feb. 10 2018 indicate a rise in the snowline, purple dots, on glaciers east of Mount Everest, indicating ablation even in winter from the terminus to the snowline. Rongbuk Glacier=R, East Rongbuk Glacier=ER Far East Rongbuk Glacier=F, Kada Glacier=K,  Barun Glacier=B,  Imja Glacier=I and Kangshung Glacier=KX.

The Mount Everest region glaciers are summer accumulation type glaciers with 70% of the annual precipitation occurring during the summer monsoon. This coincides with the highest melt rates low on the glacier.  October has been considered the end of the melt season in the region. There is little precipitation early in the winter season (November-January). The limited snowpack with warmer winter temperatures have led to high snowlines during the first few months of the winter season in recent years. There is an expanded ablation season that extends beyond October into January or February. The melt rates do to solar radiation or sublimation are not rapid, but are significant on many glaciers. This has occurred with increasing air temperatures since the 1980’s. Mean annual air temperatures have increased by 0.62 °C per decade over the last 49 years; the greatest warming trend is observed in winter, the smallest in summer (Yang et al., 2011).    The winter season of 2017-18 has been warm in the region as indicated by global temperature anomalies from, NCDC/NOAA (at right). Here we examine Landsat images from Oct. 21 2017, Nov. 17 2018 and Feb. 10 2018  on the east side of Mount Everest to observe changes in the snowline during the winter period.  We observed the same phenomenon of high snowlines and winter ablation at Nup La on the west side of Mount Everest in January of 2016, On Chutenjima Glacier, China in 2016 and Gangotri Glacier, India in 2016 (see below).

At the end of the typical melt season on 10-21-2017, the snowline is at 5850 m on Rongbuk Glacier, 6250 m on East Rongbuk Glacier, 6300 m on Far East Rongbuk Glacier, 5900 m on Kada Glacier, 6050 m on Barun Glacier and ~6100 m on Imja Glacier.

A month later on 11-17-2017 the snowline has decreased to 5700 m on Rongbuk Glacier, 6200 m on East Rongbuk Glacier, 6200 m on Far East Rongbuk Glacier, 5820 m on Kada Glacier, 5950 m on Barun Glacier and still at ~6100 m on Imja Glacier.

Three months later on 2-10-2018 the snowline has risen indicating ablation from the terminus area up to the snowline.  The snowline is at 5900 m on Rongbuk Glacier, 6400 m on East Rongbuk Glacier, 6400 m on Far East Rongbuk Glacier, 5950 m on Kada Glacier, 6200 m on Barun Glacier and 6600 m on Imja Glacier. Notice on Far East Rongbuk Glacier the snowline reaches the glacier divide in February.  The mean rise in snowline from November 2017-February 2018 on the east side of Mount Everest is 200 m.

The ablation rates necessary to raise the snowline are not large on a daily basis, but cumulatively are significant as noted on Lirung Glacier by Chand et al (2015)

Kundu et al (2015) noted that from Sept. 2012 to January 2013 the snowline elevation on Gangotri Glacier varied little, with the highest elevation being 5174 m and the lowest 5080 m. Bolch et al (2011) observed strong thinning in the accumulation zone on Khumbu Glacier, though much less than the ablation zone. This can only happen with reduced retained snowpack particularly in winter.

Landsat image from Oct. 21 2017 indicate a rise in the snowline, purple dots, on glaciers east of Mount Everest, indicating ablation even in winter from the terminus to the snowline. Rongbuk Glacier=R, East Rongbuk Glacier=ER Far East Rongbuk Glacier=F, Kada Glacier=K,  Barun Glacier=B,  Imja Glacier=I and Kangshung Glacier=KX.

 

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Purple dots indicate the transient snowline on Gangotri Glacier in the fall and early winter of 2016. Red arrow indicates the terminus of the glacier. Landsat 12-9-16

Landsat image from January 4, 2016 indicating the actual Nup La (N), west side of Mount Everest.  Purples dots is the snowline. Green arrows are expanding bedrock exposures and pink arrow a specific rock know amidst the glacier.

Popof Glacier Retreat, Alaska Features Tributary Separation

On By mspeltoIn alaska glacier retreat

Popof Glacier comparison in 1986 and 2016 Landsat images. Red arrow is the 1986 terminus location, yellow arrows the 2016 terminus location, pink arrows indicate two key tributaries and purple dots indicate the snowline.

Popof Glacier is at the southern end of the Stiking Icefield in southeast Alaska.  In 1948 the glacier had two terminus sections  that separated around Mount Basargin and then rejoined.  By 1979 the glacier termini were separated (Molnia, 2008).  Here we examine Landsat imagery from 1986-2016 to identify changes in the glacier.

In 1986 both glacier termini were located at the far end of a basin, with no proglacial lakes in existence.  The  termini were separated from each other by 400 m after nearly wrapping all the way around Mount Barsargin. The first tributary to join main glacier from both the west and east were connected to the main glacier, pink arrows.  The snowline in 1986 was at 800 m.  By 1999 the northern terminus tongue had disintegrated extending only a few hundred meters from the main glacier and forming a new lake.  A fringing proglacial lake had developed at the main or southern terminus. The snowline was at 750-800 m.  The first  tributaries entering from east and west still reach the main glacier.  In 2015 the snowline is nearly at the summit of the glacier at 925 m. The main terminus has retreated from the proglacial lake that formed in the 1990’s. The first  tributaries entering from east and west no longer reach the main glacier.  In 2016 the snowline is  at 950 m, even higher than in 2015, with less than 5% of the glacier retaining snowcover.  The main terminus has retreated 700 m from 1986 to 2016 and the northern terminus 1.7 km from 1986-2016.  The retreat is less spectacular than the nearby Shakes Glacier and Great Glacier, though both of those glaciers have retained a substantial accumulation zone.  The Popof Glacier cannot survive with snowlines as high as those seen in 2015 and 2016.

Popof Glacier comparison in 1999 and 2015 Landsat images. Red arrow is the 1986 terminus location, yellow arrows the 2016 terminus location, pink arrows indicate two key tributaries and purple dots indicate the snowline.

Popof Glacier in 1979 USGS map of the region, indicating flow directions. 

Tulsequah Glacier, British Columbia 2900 m retreat 1984-2017

On By mspeltoIn British Columbia glacier retreat

Tulsequah Glacier in 1984 and 2017 Landsat images.  The 1984 terminus location is noted with red arrows for the main and northern distributary tongue, southern distributary red arrow indicates lake margin.  The yellow arrows indicate the 2017 glacier terminus locations. The retreat of 2900 m since 1984 led to a lake of the same size forming. Purple dots indicate the snowline.

Tulsequah Glacier, British Columbia is a remote glacier draining from the Alaska-Canada boundary mountains of the Juneau Icefield. It is best known for its Jökulhlaups from lakes dammed by Tulsequah Glacier in northwestern British Columbia, Canada (Neal, 2007). The floods pose a hazard to the Tulsequah Chief mining further downstream. The continued retreat of the main glacier at a faster rate than its subsidiary glaciers raises the potential for an additional glacier dammed lakes to form. The main terminus has disintegrated in a proglacial lake. Retreat from 1890-1984 had been much slower than the last thirty years. This glacier feeds the Taku River which has seen a significant decline in salmon in the last decade (Juneau Empire, 2017). Here we utilize Landsat images from 1984-2017 to illustrate changes in this glacier, updating the retreat noted by Pelto (2017).

As part of the onoging Juneau Icefield Research Program we completed extensive snow pack measurements in the upper reach of the glacier in 1981-1984 and found that snow depths in August near the end of the melt season between 1700-2000 meters averaged 4-6 meters. This high snowfall accumulation is also indicated by modelling in a recent publication, in a project led by Aurora Roth, @ UAlaska-Fairbanks, that I participated in.

In 1984 the glacier has a low sloped terminus tongue with a narrow fringe of water indicating the initial formation of a lake. The northern distributary terminus extends 3.5 km north from the main glacier.  The southern distributary tongue that blocked the main glacier dammed lake in the past, extending south from the main glacier, now terminates near the main glacier, with the red arrow indicating the southern end of the lake basin. The snowline is at 1300 m. By 2001 the fringing lake extends along the margin for 3 km and is 200-400 m wide.  The northern distributary terminus extends just 500 m from the main glacier.  The southern distributary glacier dammed lake still forms as indicated by icebergs. The snowline is at 1450 m. The snowline is at ~1300 m. In a 2007 Google Earth image the collapsing terminus is still connected to the main glacier. By 2015 the terminus tongue has collapsed with the new proglacial lake still filled by numerous icebergs.  The southern distributary tongue no longer has icebergs indicating lake formation at this location. By 2017 the terminus has retreated 2900 m since 1984, with a new 3 km long proglacial occupying the former glacier terminus. Also note the first tributary entering the glacier from the north in 1984 no longer reaches the glacier in 2017.  The northern distributary tongue has icebergs indicating lake formation still occurs.    The snowline in 2017 is at 1450 m.  The issue driving the retreat is that the equilibrium line where melting equals accumulation and bare glacier ice is exposed has risen and is now typically at 1400 meters. Berthier et al (2018), in a paper I had the pleasure of reviewing, indicate thinning from 2000-2016 greater than 2.5 m per year below 1000 m, with some thinning extending right to the crest of the glacier in all but the northwest corner.  This will drive continued retreat. This retreat is not as spectacular as at Porcupine Glacier to the south. This is not unlike the situation at the Gilkey Glacier just delayed.

Tulsequah Glacier in 2001 and 2015 Landsat images.  The 1984 terminus location is noted with red arrows for the main and northern distributary tongue, southern distributary red arrow indicates lake margin.  The yellow arrows indicate the 2017 glacier terminus locations. Purple dots indicate the snowline.

2007 Google Earth image indicating the fialing connection of the main glacier to the terminus tongue.

How Unusual Was 2015 in the 1984–2015 Period of the North Cascade Glacier Annual Mass Balance?

On By mspeltoIn glacier climate change, North Cascade Glaciers

Sholes Glacier during the first week of August 2015 versus and average year such as in 2017.  Note stream gage and weather station at this site. The greater extent of bare ice enhances ablation as for a given temperature there is a higher ablation rate for ice then snow. Columbia Glacier a WGMS reference glacier viewed from above the glacier at Monte Cristo Pass at the start of August in 2015 and 2016.  Note the lack of retained snow in 2015 and the multiple firn layers exposed. 

This post is a shortened version of the publication out this week in Water.

In 1983, the North Cascade Glacier Climate Project (NCGCP) began the annual monitoring of the mass balance on 10 glaciers throughout the Washington mountain range, in order to identify their response to climate change. Annual mass balance (Ba) measurements have continued on seven original glaciers, with an additional two glaciers being added in 1990. The measurements were discontinued on two glaciers that  disappeared and one was that separated into several sections. This comparatively long record from nine glaciers in one region, using the same methods, offers some useful comparative data in order to place the impact of the regional climate warmth of 2015 in perspective.  This led to the most negative annual balance of the last 26 years on every glacier.

2015 Climate

The 2015 winter accumulation season featured 51% of the mean (1984–2014) winter snow accumulation at six long-term USDA SNOTEL stations in the North Cascades, namely, Fish Creek, Lyman Lake, Park Creek, Rainy Pass, Stevens Pass, and Stampede Pass. This was exceptional as it was the second lowest out of the 32 years of the mass balance observation series. The winter season was exceptional for warmth, being the warmest winter season on record in the state of Washington. The freezing level in 2015 averaged 1645 m in the Mount Baker region from November–March, compared with an average of 1077 m (John Abatzoglou, Freezing Level Tracker). The previous record for the mean November–March freezing level, since the record began in 1948, was 1500 m.

Freezing Level November-March on Mount Baker, WA from Freezing Level Tracker 1948-2017.

In 2015, the mean May–September temperature at Diablo Dam was 2.2 °C warmer than the long term mean, and it was the second warmest to 1958 in the 1950–2015 record. For June–September, the mean temperature was 2.0 °C warmer than the long term mean, and was also second to 1958 as the warmest. The combination of the warmest melt season in over 50 years and the second lowest accumulation season snowpack in the last 30 years was a good indication that the glacier mass balance would be quite negative.
In 2015, the sea surface temperature waters that had developed in the winter of 2013/14, persisted off the coast of the Pacific Northwest, with anomalies generally exceeding 2 °C (Di Lorenzo and Mantua, 2016)

Glacier Mass Balance 2015

The mean annual balance of the NCGCP glaciers is reported to the World Glacier Monitoring Service (WGMS), with two glaciers, Columbia and Rainbow Glacier, being reference glaciers.  The mean Ba of the NCGCP glaciers from 1984 to 2015, was −0.54 m w.e.a−1 (water equivalent per year), ranging from −0.44 to −0.67 m w.e.a−1 for individual glaciers. In 2015, the mean Ba of nine North Cascade glaciers was −3.10 m w.e., the most negative result in the 32-year record. The correlation coefficient of Ba was above 0.80 between all North Cascade glaciers, indicating that the response was regional and not controlled by local factors. In 2015, out of the nine glaciers where the Ba was examined, the AAR was 0.00 on seven of the glaciers, 0.05 on the Rainbow Glacier, and 0.26 on the Easton Glacier. For each glacier, the 2015 Ba was the most negative of any year in their entire record. The South Cascade Glacier had a negative mass balance of −2.72 m w.e. in 2015, which was the most negative Ba reported since the suite of continuous mass balance measurements began in 1959 [USGS, 2017].  The probability of achieving the observed 2015 Ba of −3.10 is 0.34%.

 
Annual mass balance of North Cascade glaciers, note the similar annual response indicating regional climate conditions are the overriding driver of mass balance. 

On June 15, when the automatic weather station and discharge station were installed adjacent to the Sholes Glacier, the snowpack was similar to a typical early August snow cover. On the Sholes Glacier, the AAR fell from 0.55 on 9 July to 0.00 on 9 September. This was the first year since the monitoring had begun in 1984 that the mean AAR in early August was below 0.25. The result was an exposure of the older firn layers and a general decrease in albedo. In early August, the AAR was below 0.1 for all of the glaciers, except for the Easton Glacier. On the Columbia Glacier, the AAR on August 1 was the lowest observed yet at 0.12, with six weeks remaining in the melt season. The early exposure of glacier ice was important as the melt rate was faster, as was indicated by the greater melt factor.  The North Cascade mass balance cumulatively over the last 30 years matches closely the global mean mass balance loss.

Map of North Cascade glaciers observed in this study. 

Comparison of North Cascade cumulative and Global cumulative glacier mass balance

 

Lago Cholila, Argentina Headwaters Glacier Retreat Lake Formation

On By mspeltoIn argentina glacier retreat

Changes in four glacier at the headwaters of Rio Tigre, Argentina in 1987 and 2017 Landsat images.  The red arrow indicate the 1987 terminus position and the yellow arrow the 2017 terminus position. 

Glaciers form the headwaters for Lago Cholila which drains into  Futaleufu River in west central Argentina .  Davies and Glasser (2012) mapped the glaciers in the Hornopiren region just to the northwest and Parque Nacionale
Corcovado just to the southwest  finding a 13-15 % area loss from 1986 to 2011. Here we examine the changes of four of the glaciers in Landsat images from 1987-2017.

In 1987 only one of the four glaciers terminates in a lake #1, #2, and #3 end at the far end of a cirque basin and #4 terminates at the downvalley end of a basin.  Glacier #3 also has a 400 m wide connection from the upper to the lower glacier, pink arrow.  By 2000 a small terminus lake has appeared at #2 and #4, while #1 has retreated around a bend in the lake.  In 2016 the upper and lower portion of #3 have nearly separated, pink arrow.  No lake has yet formed. By 2017 #1 has retreated 700 m since 1987, with the remaining glacier only 1400 m long.  Glacier #2 has retreated 500 m with a new lake of the same width having developed.  Glacier #3 thinning instead of retreat has dominated.  The glacier will continue to lose its terminus tongue, with the lower glacier effectively cutoff from the upper glacier. Glacier #4 has retreated 600 m, with a new lake having formed, and the terminus now having retreated upglacier of the lake.  The headwaters of the Lago Cholila has and is losing significant glacier volume, which is leading to new and expanding lakes. Below a Google Earth image indicate the new lake and the limited accumulation zone on Glacier #4.  The retreat is similar to that we reported for the Sierra de Sangra to the south and Pico Alto just to the north in Chile.

Changes in four glacier at the headwaters of Rio Tigre, Argentina in 2000 and 2016 Landsat images.  The red arrow indicate the 1987 terminus position and the yellow arrow the 2017 terminus position. 

Google Earth image indicating new lake formed by retreat of Glacier #4.

Qiaqing Glacier Retreat & Lake Expansion, China

On By mspeltoIn china glacier retreat

Qiaqing Glacier in 1992 and 2017 Landsat images indicating flow, blue arrows, 1992 terminus at red arrow and 2017 terminus at yellow arrow. tributaries A, B and C. 

“Qiaqing” Glacier drains southeast from the Kona Kangri Massif at the eastern part of the Nyainqentanglha Shan. The glacier ends in a lake before feeding into the Parlung Zangbo and then Yarlung Tsanpo. This glacier feeds the Parlung Zangbo which is the site of numerous planned hydropower projects, last image, before joining the Yarlung Tsanpo which becomes the Brahmaputra River. The Zangmu Dam went online in 2015, this hydropower facility will produce 2.5 billion kilowatt-hours of electricity a year.  Wu et al. (2016) examined glacier change in the Nyainqentanglha Range from 1970-2014 noting an accelerating shrinkage of glaciers,with glacier area decreasing by 244  km2 or ~27%, with the western part of the range faring worse.  Wang and others (2011) note in the nearby Boshula Range that glacial lakes have expanded from 1970-2009 by 19% and the area that is glacier covered has decline by 13% during the 1970-2009 period.

Here we examine Landsat images from 1992 to 2017 to identify changes of Qiaqing Glacier. In 1992 the glacier terminated in a 1.5 km long proglaical lake with tributary A just separated from the glacier and tributary B and C joining the glacier on a wide front. In 1999 the snowline is at 5200 m the glacier has retreated several hundred meters and the blue ice of tributary B and C still reach the main glacier.  In 2015 the snowline is at  5000 m.  In 2016 the snowline is at 5200 m, a few icebergs are visible in the lake and tributary B and C  are disconnecting from the glacier, and the terminus has retreated upvalley from the former location of connection with tributary A.  By 2017 the terminus has retreated  1700 m since 1992, a rate of ~68 m/year.  The proglacial lake is now over 3 km long. The retreat is enhanced by the lake, but not driven by it.  The high snowlines above 5000 m leave an insufficient accumulation zone to maintain the current glacier size. The retreat here is similar to that of Thong Wuk Glacier and Jiongla Glacier.

Qiaqing Glacier in 1999, 2015 and 2016 Landsat images; 1992 terminus at red arrow and 2017 terminus at yellow arrow.  Purple dots indicate the snowline. 

Pico Alto Glacier, Chile Retreat New Lake Formed

On By mspeltoIn chile glacier melt, chile glacier retreat1 Comment

Pico Alto Glacier, Chile in 1986 and 2017 Landsat images indicating the retreat.  Red arrow indciates 1986 terminus, yellow arrow the 2017 terminus,and purple dots the snowline. 

Pico Alto Glacier, Chile drains north from the Argentina-Chile border entering the Rio Puelo and eventually Lago Tagua. The glacier ongoing retreat is similar to the nearby Hornopiren Glacier and Erasmo Glacier.  Davies and Glasser (2012) mapped the glaciers in the Hornopiren region and found a 15 % area loss from 1986 to 2011.

In 1986 there was no lake at the terminus of the glacier and the snowline is near the main junction.  By 2000 the glacier had retreated 1200 m opening a new lake.  The eastern arm of the glacier did not retain significant accumulation. In 2016 the snowline again left the eastern tributary without retained accumulation.  In fact the connection to the larger western tributary has been greatly reduced.  By 2017 the glacier has retreated 2.4 km with a lake of nearly the same length having formed, this is 40% of the total glacier length lost in three decades.  The eastern tributary due to a lack of retained snowpack will continue to wither away.  The main glacier can survive in a reduced state with current climate. Wilson et al (2018) noted a substantial growth in the number of lakes in the central and Patagonian Andes due to the ongoing rapid retreat. Harrison et al (2018) also observed the number of glacier lake outburst floods have declined despite the increase in lakes.

Pico Alto Glacier, Chile in 2000 and 2016 Landsat images indicating the retreat.  Red arrow indicates 1986 terminus, yellow arrow the 2017 terminus,and purple dots the snowline.

Google Earth view of the Pico Alto Glacier (PA) indicating flow, blue arrows, 1986 terminus red arrow and 2017 terminus yellow arrow

Mityushikha Ice Caps Separation, Novaya Zemlya

On By mspeltoIn Novaya Zemlya glacier retreat

Mityushikha Ice Cap (M) and West Mityushikha Ice Cap (WM) arrows indicating locations of glacier  separation or glacier margin change. 

Mityushikha Ice Caps are a group of small ice caps near the southern end of the glaciated mountains of Novaya Zemlya. Here we examine two of these ice caps using Landsat imagery from 1994-2017. Much attention has focused on the retreat of the larger tidewater glaciers of Novaya Zemlya, that between 1992 and 2010 retreat rates were an order of magnitude higher for tidewater glaciers outlets (52.1 m/year than for land-terminating glaciers 4.8m/year Stokes et al (2017).  Carr et al (2017 ) observed that glacier retreat between 1973/76 and 2015 in Novaya Zemlya terminating into lakes or the ocean receded 3.5 times faster than those that terminate on land. Both studies focus on terminus retreat, here we also can observed the accumulation area ratio and area losses.

A comparison of the two ice caps Mityushikha (M) and West Mityushikha (WM), at nine locations between 1994 and 2016 indicate a consistent pattern. The most striking aspect is the lack of retained snowpack on the WM ice cap in 2016, while M ice cap has limited retained snowpack.  This pattern of snowpack loss is evident in other years and has led to the changes observed between 1994 and 2016.

  • Point 1: The northern glacier has disconnected from the ice cap.
  • Point 2: A significant expansion of bedrock leading to reduced glacier connection.
  • Point 3: The ridge has extended west toward the ice cap margin.
  • Point 4: The two outlet glaciers have separated.
  • Point 5:  The southern glacier has separated from the rest of the ice cap.
  • Point 6:  Separation of the southern glacier from the WM.
  • Point 7: Expansion of bedrock exposed areas.
  • Point 8: Expansion of bedrock area amidst ice cap.
  • Point 9: Separation of northern glacier from ice cap.

A comparison of Landsat images from 2001 and 2017 indicate retreat of outelt glaciers fro the Mityushikha Ice Cap at six locations.

  • Arrow 1: A 300 m retreat
  • Arrow 2: A 600 m retreat
  • Arrow 3: Separation from #2 and 600 m retreat.
  • Arrow 4: A 150 m retreat.
  • Arrow 5: A 500 m retreat
  • Arrow 6: A distributary terminus of #1 a 500 m retreat

The rate of retreat of these small ice cap glaciers is higher than reported by Stokes et al, (2017) or Carr et al, (2017)  What is also evident is the significant area and volume losses.  Mass losses indicate that climate change is not just affecting glaciers via increased calving losses. The changes are not as eye catching as the retreat of large outlet glaciers, leading to new island formation, Nizkiy Glacier, but is similar to that seen at Lednikovoye Glaciers.

Mityushikha Ice Cap with red arrows indicating six glacier terminus that have retreated from 2001 to 2017 in Landsat images.

North Cascade Winter Snowpack Status 2018

On By mspeltoIn North Cascade Glaciers

2018 Winter Freezing levels at Mount Baker (November 2017-March 2018). 

The accumulation season on most Northern Hemisphere glaciers extends through April. The key benchmark for snowpack water assessment in alpine ranges is typically April 1, as that is the average maximum snowpack for an alpine range.  In 2018 the North Cascade Range had freezing levels above the long term mean, but at the 21st century mean.

A result of higher freezing levels is more rain on snow events and winter melt events.  This reduces the retained April 1 snowpack, which is measured as snow water equivalent (SWE).  An examination of the trends in April 1 SWE at the six long term North Cascade stations, winter precipitation at the most reliable North Cascade weather stations, and the ratio between the two indicates a similar decline in snowpack and snowpack/winter precipitation ratio, while winter precipitation has increased.   The  ratio between SWE and precipitation, snowpack storage efficiency-on right axis, has been in decline,  as noted by Mote et al (2008) and Pelto (2008).  This ratio change has driven most of the SWE.

For 2018 precipitation is 2.7 m with, 1.1 m of that retained on average as April 1 SWE.  The April 1 SWE is similar to the 2016 and 2017 values.  

At the sites closest to the glaciers with snowpack measurements the April 1 snow depth is 4.21 m at Lyman lake and 4.24 m at Mount Baker ski area.  At Stevens Pass there is a snow depth of 3.53 m, which is approximately the average, webcam image below is from 4/6/2018. As winter wraps up, snowpack is relatively normal despite a winter of wide temperature fluctuations, Feb freezing levels 400 m below the mean and December 500 m above the mean. The glaciers still have 3-6 weeks for accumulation to build up, while melt get underway lower on the mountains.  We will be in the field again in 2018 to examine snow depths and melt across the North Cascade glaciers.

A view up toward the icefall on Easton Glacier at 2000 m.

Stevens Pass ski area from Webcam 4/6/2018

Monte Cristo Range waiting for spring to begin

Mount Baker coated with March 2018 snowpack.

 

Warsaw Icefield, King George Is., Antarctica Retreating from Shoreline

On By mspeltoIn Antarctic Glacier retreat

Warsaw Icefield, King George Island, Antarctica glacier retreat and nunatak expansion in 1989, 2001 and 2018 Landsat images. E=Ecology Glacier, B=Baranowski Glacier, W=Windy Glacier, 1989 terminus locations indicated by red arrows.  Point A & B are nunataks. 

The Arctowski Polish Research Station is located on a relatively large ice-free oasis northeast of the Warsaw Icefield on King George Island, Antarctica. The station is on Admiralty Bay where  Ecological monitoring has been conducted since the late 1970’s in order to determine the size and condition of populations of seabirds and pinnipeds. The ocean bottom has had over 800 distinct benthic species identified. A long term study of a chinstrap penguin colony on King George Islands during the last 30 years indicates the size of the breeding populations has decreased by 84% probably due to limitations of the marine food web (Korczak-Abshire et al 2012). The outlet glaciers of Warsaw Icefield experienced significant retreat and mass loss (Petlicki et al, 2017). Here we examine Landsat images from 1989 to 2017 to illustrate the changes.  The Warsaw Icefield extends from 400 m to sea level.

In 1989 Baranowski and Windy Glacier terminate on the coastline lacking any significant embayment.  Ecology Glacier has a wide front in a shallow embayment.  Nunataks A and B are amidst the icefield. In 1990 the snowline is at 200 m with nunatak A and B in the ablation zone.  In 2001 nunatak A and B are still surrounded by ice.  Windy Glacier and Baranowski Glacier have retreated with embayments forming.  The embayments are separated from ocean by a coastal strip of land.  An embayment has also opened to the west of Windy Glacier and Point C due to glacier retreat. In 2005 the snowline is at 250 m.  Baranowski glacier retreat has led to Nunatak B reaching the margin of the glacier, the embayment expanding on the north side of the margin. In 2014 Ecology Glacier has retreated opening the embayment.  In 2018 Ecology Glacier has retreated 600 m since 1989 exposing several small new islands in this protected embayment.  the Tidewater front is quite limited in 2018. Nunatak A is within 400 m of the edge of the icefield, whereas in 1989 the nunatak was 1.2 km from the margin. The 1989-2018 500 m retreat of Baranowski Glacier has led to the development of a dominantly land based terminus. Windy Glacier has retreated 400 m since 1989 and is now land terminating. The glacier to the west of Windy Glacier and Point C has opened a 0.5 square kilometers embayment. The retreat of Warsaw Icefield is similar to that of Endurance Glacier, Elephant Island.  Petlicki et al,( 2017) indicate mass balance has not been as negative from 2012-2016 which should slow retreat.  The new embayments offer potential new locations for penguins that Arctowski scientists will monitor.

Warsaw Icefield, King George Island, Antarctica glacier retreat and nunatak expansion in 1990, 2005 and 2014 Landsat images. E=Ecology Glacier, B=Baranowski Glacier, W=Windy Glacier.  Point A & B are nunataks in 1989. 

Map from the Arctowski Research Station in 2007 indicating glacier changes from 1978 mapped margins to 2007 dark line margin.  This dark line has been annotated to be visible for this post. 

Cook Ice Cap Retreat & Nunatak Expansion, Kerguelen Island

On By mspeltoIn kerguelen island glacier retreat1 Comment

West margin of Cook Ice Cap in 2001 and 2018 Landsat images.  Red arrows indicate terminus margin in 2001 in both images. Nunataks A-D and Nunatak Lacroix (L) are also shown.

On the west side of the Cook Ice Cap on Kerguelen Island a series of outlet glaciers have retreated and several nunataks have either expanded or are no longer surrounded by ice.   The glacier include Pasteur, Pierre Curie, Larmarck and Descartes from north to south. Here we examine the changes from 2001-2018 along using Landsat imagery.  This is a very cloudy region and no other images allowed a clear view, except a Sentinel image also from 2018. Retreat of glacier in the region was examined by Berthier et al (2009) and is exemplified by the retreat of Ampere Glacier.  Verfaillie et al (2016)examined the surface mass balance using MODIS data, field data, and models.  They identified that accelerating glacier wastage on Kerguelen Island is due to reduced net accumulation and resulting rise in the transient snowline since the 1970s, when a significant warming began.

On the west side of Cook Ice Cap in 2001 there is one significant Nunatak in the midst of the ice cap Nunatak Lacroix (L). Nunatak A and D do not exist.  Nunatak C is encircled by ice and Nunatak B is nearly surrounded. Pasteur Glacier reaches tidewater across a broad front in 2001. By 2018 Nunatak D has emerged 1.2 km inland from the margin. Nunatak A has also emerged 4.0 from the ice margin. Nunatak C is now a ridge separated from the ice cap. Lacroix Nunatak is much expanded. Pasteur Glacier is narrower has retreated 600 m and does not reach tidewater, but terminates on a proglacial delta. Pierre Curie Glacier 1.2 km and is now just 2 km from the ice cap margin. Lamarck Glacier that terminated in a proglacial lake has now retreated from that lake, a retrated 1100 m.  Descartes Glacier  has retreated 1000 m with a narrow arm of the lake extending northward. A new proglacial lake has also formed down glacier of Nunatak D.  The retreat of the western margin of the Cook Ice Cap supports the mass balance losses determined by  Verfaillie et al (2016).  The east side of the Cook Ice Cap is also retreating forming a new lake district.

West margin of Cook Ice Cap in  2018 Sentinel image.  Red arrows indicate terminus margin in 2001 in both images.  Nunataks A-D and Nunatak Lacroix (L) are also shown. Retreat of outlet glaciers at the five arrows is 900 m.

 

Heilprin Glacier, NW Greenland Pinning Point Decline 1987-2017

On By mspeltoIn Greenland glacier retreat

Heilprin Glacier in 1987 and 2017 Landsat images.  The ice front is shown with yellow dots. Island A, Island B and Point C also are noted. Island A and B both have reduced ice contact, but remain as important pinning points. How much longer for Island A?  Retreat from 1987-2017 is 1.6 km to the south, 1.1 km in the center and 2.2 km on the northern margin.

Heilprin Glacier is an outlet glacier in northwest Greenland. Along with the neighboring Tracy Glacier it drains ~12,000 square kilometers of the ice sheet into Inglefield Bay.  Hill et al (2017)  note that neither glacier has a floating tongue and that Tracy Glacier has retreated faster. The velocity of Tracy Glacier is also higher than Heilprin Glacier, with most of the calving front exceeding 1200 m/year (Joughin et al, 2010).  Heilprin Glacier has a only a narrow section on the northern side that exceeds 1000 m/year (Joughin et al, 2010). Sakakibara and Sugiyama (2018) examined glacier velocity and frontal positions of 19 glaciers in the region including Tracy and Heilprin Glacier. They  observed that retreat began in ~2000 which coincided with a regional rise in summer mean air temperature.  The outlet glaciers also accelerated and those that did had the greatest acceleration generally retreated the most. Here we examine Landsat images from 1987-2017 illustrating terminus changes.

In 1987 The Heilprin Glacier front was 12 km long with two islands providing pinning points and separating the terminus into three calving regions.  The southernmost was south of Island A, Lille Matterhorn, which was 1.7 km wide and extended 1.6 km west from the east end of Lille Matterhorn, total ice contact was 2.4 km.  Island B was in contact with the ice on the east side from the southwest to the northwest corner, 3.5 km.  The northern segment was the longest calving front at 5.6 km ending at Point C.  By 1998 the glacier southern segment at Island A had changed little. Island B was still in contact with the ice along its east side from the southwest to northwest corner.  The northern segment had retreated from Point C by 1.4 km.  In 2009 retreat south of Island A has begun. In 2017 at Island A the glacier was barely in contact with the island with the southern most calving section having retreated 1.5 km since 1987.  Island B was still in contact with ice on the east side from the southwest corner, but no longer at the northwest corner.  retreat from the northwest corner is 1.1 km. The total contact with Island B in 2017 is 2.6 km, 70% of the 1987 contact.  At Island A the contact is 0.2 km a 90% reduction since 1987.  When Island A separates the loss of this pinning point will enhance retreat of the southern section of the ice front. The northern margin near Point C has retreated 2.2 km since 1987. Sakakibara and Sugiyama (2018)  identify a velocity change in the terminus reach of 13 m/a from 2000-2014.  They also note the retreat rate increased to 109 m/year from 2000-2014.

Heilprin Glacier in 1998 and 2009 Landsat images.  The ice front is shown with yellow dots. Island A, Island B and Point C also are noted. 

Nuna GIS map of the region indicating Island A and B and Point C. The margin here is from before 2000.