Anderson Glacier, Olympic Mountains, Washington Disappears

On January 9, 2015January 9, 2015 By mspeltoIn glacier climate change, Glacier Observations

Anderson Glacier was the headwaters of the Quinault River in the Olympic Mountains of Washington. A century ago the glacier was 2 km long, and a half kilometer wide. Retreat of this glacier in the first half of the 20th century exposed a new alpine lake as the glacier retreated 1 kilometer. From 1950-1980 the glacier diminished slowly. From 1959 to 1990 the glacier thinned and retreated from the shore of the lake trapped behind the Little Ice Age moraine. The 1959 picture below was donated to me by Austin Post. Since 1990 the glacier has begun to shrink rapidly. The Google Earth image from 1990, indicates Anderson Glacier has retreated 200 m from the 1959 terminus position near the lake shore, green arrow to the 1990 position, pink arrow. The red arrow indicates a future location of a bedrock outcrop.
1959 Austin Post image

1990 Google Earth image

Investigating this glacier in 1992 we measured its area at 0.38 square kilometers, down from 1.15 square kilometers a century before. Ten years later the glacier had diminished to 0.28 square kilometers, but had thinned even more, leaving it poised for a spectacular change, over the next five years. Large outcrops of rock appeared beginning in 2003 and further exposed in 2005 and 2007 in the middle of the glacier. Note the outcrops in the 2007 image from Kathy Chrestensen. The 2009 Google Earth image indicates the 1990 terminus position, pink arrow, and the fact that there is no longer a ribbon of snow that is even 50 m wide. The snow patches have insufficient size or thickness to be classified as a glacier. The largest outcrop at the red arrow had been beneath the ice in 1990, giving a scale to the thinning. The glacier at this point no longer exists. In 2014 an Eric Hovden image indicates some seasonal snow in the basin, but the thin ribbon of snow has numerous holes in it as well, indicating the thin nature of the remaining snow patches, with a month left in the 2014 melt season.

Kathy Chrestensen Image

2009 Google Earth Image

2014 Eric Hovden image.

This glacier had become a series of small disconnected relict glacier ice patches in 2005 and by 2009 had disappeared. It is not the only glacier that is disappearing, which has led to a visual model for forecasting glacier survival (Pelto, 2010). The key is observed retreat of the margin of the upper portion of the glacier and emerging rock outcrops in the upper part of the glacier where snow should accumulate and be retained through the melt season. If a glacier does not have a significant persistent accumulation zone it cannot survive. Anderson Glacier was not the only glacier feeding the Quinault River, all the others are retreating as well. The result of this glacier retreat is reduced late summer and early fall streamflow, impacting salmon runs at that time of the year. This is primarily the fall Coho, Chum and Chinook salmon and Steelhead summer run. During the spring and early summer runoff increases as snowmelt still occurs, but is not retained in the glacier system.To get a sense of the special nature of this area Out of the Mist is an excellent start

Galaxy Glacier Rapid Retreat, Pukulkul Basin Glacier disappears, British Columbia

On May 21, 2013 By mspeltoIn Glacier Observations2 Comments

Over the ridge south from Stave Glacier is a 1.5 km long unnamed glacier, that is on the west flank of Galaxy Peak, hence referred to here as Galaxy Glacier. The glacier is in Garibaldi Provinical Park, British Columbia. Koch et al (2009) in their detailed survey of glaciers in the park chronicled the Park’s glacier retreat from 1952 to 2002. Koch et al (2009) Found that all 45 glaciers are retreating, and Stave Glacier was experiencing its fastest retreat from 1976-1996, with a 750 m retreat. Satellite imagery from 2012 indicates the Stave Glacier retreat rate from 1996 to 2012 is 1600 m or 100 m per year, even faster. Here we utilize Landsat imagery from 1985, 1987, 1992 and 2009, plus Google Earth imagery form 2006 to examine the retreat and separation of Galaxy Glacier. The orange arrow indicates the terminus of the Galaxy Glacier (G) in 1985 where it joined the glacier (P) in the Pukulkul Basin where several lakes have been forming. This basin is just north of Pukulkul Peak. In 1985 Galaxy Glacier and the Pukulkul Basin Glacier are joined at the orange arrow, the red arrow marks the 2009 terminus and the purple arrow indicates the connection to the highest accumulation area on the east slope of Corbold Peak. By 1987 Galaxy Glacier has separated from the Pukulkul Basin Glacier, the latter has an area of 0.45 square kilometers and is larger than the lake it ends in. By 1992 the Galaxy Glacier is separated by 500 meters from Pukulkul Basin Glacier. The area of bare rock at the purple arrow at the top of Galaxy Glacier has expanded. By 2006 the Pukulkul Basin Glacier is gone and a 2.5 km long series of lakes is in its place. Galaxy Glacier has retreated 800 m from the new lake, and 650 meters from its 1985 position. The purple arrow indicates two large rock outcrops effectively ending significant glacier inflow from the upper east slopes of Corbold Peak. By 2009 the Pukulkul Basin Lake has a deeper blue as the glacier input has declined. The glacier is 90% bare of snowcover and the bedrock at the purple arrow has continued to expand. A closeup of the glacier from the 2006 Google Earth imagery indicates exposed firn layers at the blue arrows. This indicates that all the snowcover not just from the most recent winter has been lost but a number of previous winters as well. This is indicative of a glacier that has no consistent accumulation zone and cannot survive (Pelto, 2010). This glacier similar to the nearby Helm Glacier cannot survive current climate. The purple arrows indicate the limited connection to the upper slopes of Corbold Peak. The red arrow indicates the current terminus position. Galaxy Glacier has lost half of its area in the last 25 years, and the 800 m retreat is one-third of its total length.
1985 Landsat

1987 Landsat

1992 Landsat

2006 Google Earth

2009 Landsat

2006 Google Earth Cloesup

Death of a Glacier, Whitechuck Glacier, Washington

On February 17, 2013March 14, 2014 By mspeltoIn Glacier Observations2 Comments

The Whitechuck Glacier supplies flow to the headwaters of the Whitechuck River. Its white expanse has graced these headwaters for thousands of years. The Whitechuck Glacier retreated slowly from its advanced Little Ice Age position until 1930, while rapidly thinning. Thus, prepared it began a rapid retreat in 1930. This rapid retreat culminated in the total disappearance of the north branch of the glacier in 2001. No more does this glacier dominate the headwaters, and its demise has and will continue to alter the hydrology of the Whitechuck River headwaters. How did this glacier die and what are the impacts when a glacier disappears? This is the glacier that also led to the first glacier survival forecast model.

A progressive temperature rise from the 1880’s to the 1940’s led to ubiquitous retreat of North Cascade glaciers. The Whitechuck Glacier was no exception: by 1950 the glacier’s northern terminus had retreated 1050 m and the southern terminus 750 m. More importantly the glacier had thinned dramatically. The glacier had flowed down relatively gentle slopes into a large flat basin. The 1967 aerial photograph of the area from Austin Post, USGS indicates the two merged branches of the glacier North Branch (NB) and south Branch (SB), note the lack of snowcover on the North Branch (Figure 1).

The USGS topographic maps of Glacier Peak from 1958 show the still large Whitechuck Glacier with an area of 3.1 km2 (Post et al., 1971). The USGS remapped the area based on aerial photographs from 1983.and this map still has two branches with two termini, the northern branch feeding the northern terminus, and the southern branch feeding both the northern and southern terminus. Both branches exceeded a mile in length in the 1950’s (Figure 2).

The 1984 the USGS maps of the East Glacier Peak and West Glacier Peak quadrangles indicate the southern terminus had retreated 450 m, from the 1958 map terminus position. The northern terminus had retreated 180 m and was still near the lip of a basin at 1975 m. In 1988 during our field visit the southern terminus of the glacier ended in a new lake #1 at 2020 m (Figure 3). The lake is not in evidence on the 1984 updated USGS topographic maps or in 1979 aerial photographs of the area. The terminus had retreated 510 m since 1955, and 140 m since 1967. The lake that had been the terminus location in the 1958 map still exists, but is now 375 m from the edge of the new terminal lake, and has recessional moraines evident (Figure 4). The south branch of the glacier is thin and stagnant in the lower 200 m. Above this point crevasses are in evidence and the convex profile indicates that the south branch was still an active glacier in 1988. This remains the case in 2005, while in the former location of the north Branch several small lakes are evident where the glacier used to be.

The northern terminus of the Whitechuck Glacier ends in a lake basin at 1980 m in 1988. This basin was filled with glacier ice in 1967. In 1988, the new lake was 210 m long and still expanding. Total retreat of the terminus from 1955-1988 was 410 m. The northern half of Whitechuck Glacier extending up to Glacier Gap was a rapidly melting, concave, stagnant ice mass in 1988. The north branch had no crevassing and even the ice at the glacier surface lacks the normal blue ice color of glacier ice. Instead it was a dull dark grey color. The distance from the terminus to the top of this section of glacier is 1550 m. Total glacier area has decreased from 3.1 km2 in 1958 to 1.8 km2 in 1988 (Figure 5).

1995 the southern terminus had retreated an additional 50 m expanding the lake #1 at the terminus (Figure 6). The south branch of the glacier no longer actively feeds the northern terminus, as the ice had become to thin for motion. The glacier ended in the lake on a gentle slope. The northern lobe was stagnant ice with no retained snowcover, and was only a narrow 500 m long section of ice, we quickly ascended this section on crampons in 1995. The upper most section had separated from the main body of the glacier at 2134 m. The area of the glacier had declined to 1.6 km2 in 1995.(Figure 7)
In 2002, the northern branch of the glacier was entirely gone. Instead of an ice filled valley extending 1.6 km from the lake to Glacier Gap at the former head of the glacier, there was a boulder-filled basin. There is a new lake #3 that has developed at 2000 m, 400 m northeast of the terminus lake #2. The walk to Glacier Gap took much longer picking our way through the loose bouldery terrain.

Upon our return in 2002 the entire northern branch was gone. The southern branch was thin and viewed from the 1950 terminus position lake illustrates the retreat. The southern lobe of the glacier is still thinning slowly, and retreating. A comparison of glacier surface elevation in 1983 and 2002 identifies the average thinning in the twenty year period from the USGS aerial photography in 1983 to 2002, for the northern branch is 15 m. For the southern branch the average thinning is 6 m. The total area of glacier ice left including the stagnant section by the northern terminus is 0.9 km2 less than 30% of the area of just 30 years ago. At the current rate of thinning and given the current ice thickness of 35 m this glacier will endure for the first half of this century. The south branch is not close to equilibrium and though its retreat is hastened by the recent warm weather. A comparison of the glacier viewed from Glacier Gap illustrates the change, in 1973. A view of the basin in 2005 indicates the four lakes that have formed the lack of a north branch and the limited snowcover on the south branch. (Neil Hinckley photo) and 2006 (Leor Pantilat photo) (Figure 8 and Figure 9)

The largest and deepest is Lake #2 this is where the two glaciers used to intersect. A 2006 Google Earth view illustrates the glacier extent down to 0.7 km2 in 2006 from 3.1 km2 in 1958 (Figure 10and 11) .

The retreat of this one glacier has led to the development of six new lakes, three in the last thirty years. By 2010 the relict ice around lake #2 was gone (Figure 12).
The 3.4 km2 of new bare bouldery surface can be slowly colonized by vegetation. Compared to many areas of glacial retreat where natural revegetation takes place fairly rapidly, there it is an achingly slow process, where even the portions of the basin exposed for fifty years have gained little colonizing vegetation. This may be because of the extremely limited growing season (the basin still has snowcover into July), and its relative isolation from seed sources. The loss of area has impacted glacier biota, such as ice worms, springtails, algae, bacteria, and other invertebrates and microbial organisms living on and in under these glaciers. This represents a substantial loss in biological processing and material that would otherwise be transferred downstream.

The amount of runoff entering the Whitechuck River has declined substantially in the summer. For thousands of years each square meter of glacier has contributed 800 gallons of runoff from July I-October 1. With the loss of glacier ice, this contribution should drop by 65-80% based on observations at two other sites where glaciers have disappeared (Pelto, 1993 & 2008). The change since 1950 in glacier area has reduced summer glacier runoff by 1.5 billion gallons annually. This represents a loss of between 20 and 25 cfs for the Whitechuck River during the July-September period. The water will also be less sediment laden and warmer. The impact will be less water for the fall salmon runs, and less food in amount and processing for stream invertebrates on which salmon feed downstream in the Sauk and Skagit Rivers. This mirrors the change in the Skykomish River Basin (Pelto, 2010). Two of the field visits to this area were with the late Cliff Hedlund, Corvallis, OR who did in fact sew his own gear.