Chickamin Glacier Retreat, North Cascade Range, Washington

Chickamin Glacier covers the north slope of Sinister Peak in the North Cascade Range of Washington.  The glacier has a valley tongue that descends to an outwash plain.  Here we examine retreat of the glacier from 1979 to 2012. The glacier had advanced from 1955-1975, before commencing retreat.

Chickamin Glacier (Tom Hammond)

chickamin map

USGS Map of Chickamin Glacier

In 1979 the glacier terminus was at the pink arrow, several hundred meters beyond a prominent buttress, red arrow, where the glacier turns west.  The lowest icefall is indicated by a green arrow. In 1991 the glacier has retreated from the pink arrow, but still is turning the corner beyond the buttress.  The lower icefall is still extensively crevassed.  By 1998 in a Google Earth image the terminus is outlined with yellow dots and has retreated 230 m from the 1979 position.  The lower icefall is still crevassed.  By 2005 in a photograph from Tom Hammond (North Cascades Conservation Council), the glacier has retreated to the buttress. in a 2006 Google Earth image the terminus position is indicated by yellow dots, with a retreat of 50 m since 1998.  The lower portion of the glacier has limited crevassing.  In the 2012 image the glacier terminus no longer reaches the buttress and has retreated 360 m since 1979. We observed exceptional ablation conditions in the North Cascades in 2013 and 2014, which combined with exceptionally low snowpack in 2015 will lead to a continued significant retreat of this glacier.  The crevassing in the lowest icefall has declined and is now superficial. All 47 glaciers observed by the North Cascade Glacier Climate Project have been retreating and four have disappeared (Pelto, 2011). This glacier is similar in size and retreat to Boston Glacier and Honeycomb Glacier.


Chickamin Glacier 1979 (Austin Post)chickamin glacier1991

1991 Chickamin Glacierchickamin 1998 geterminus

1998 Google Earth image


2005 Chickamin Glacier (Tom Hammond)chickamin 2006 geterminus

2006 Google Earth imagechickamin 2012 geterminus

2012 Google Earth Image

Boston Glacier Retreat, North Cascade Range, Washington

Boston Glacier is the largest glacier in the North Cascades with an area of just over 6 square kilometers. The is a steep, wide slope glacier that currently lacks any type of main terminus tongue or valley section. The glacier is extraordinarily heavily crevassed this is due a steep slope, a smooth hard bedrock basal slope and high accumulation rates. In 1986 the first time I stepped onto this glacier is was immediately apparent that traversing the glacier in any direction was not wise and this glacier would be a poor choice for detailed observations. Richard Hubley, UWashington in the 1950’s chronicled the beginning of an advance for the glacier. A series of aerial photographs of this glacier from 1960 to 1979 by Austin Post, USGS indicate the glacier remained in an advanced position. By 1998 Granshaw and Fountain (2006) noted retreat and glacier area loss had begun. Here we examine a series of images from 1955-2014 to identify the changes in the terminus and crevassing on this glacier.

In each image C,I and T are in the same location. In 1955 the Richard Hubley image indicates the main terminus has advanced down a steep bedrock step to a small basin, I indicates the west side of the step. In 1972 an Austin Post image indicates the main terminus has descended a second step to end at a small lake basin (T). The crevasse density in a grid of 40,000 square meters around point C indicate that 55% of the glacier surface is a crevasse feature. A 1998 Google Earth image indicates the terminus has retreated from the small lake basin (T) but is still below the steep bedrock step (I), a 200-250 m retreat. At Point C crevassing has been reduced to 30% of the surface area.

1955 Richard Hubley image

Boston glacier 1972
1972 Austin Post image

boston 1998
1998 Google Earth image

By 2005 and 2006 the glacier has retreated from the basin below the steep bedrock step a retreat of 650 m since 1972, and 400 m since 1998. Crevassing at Point C is nw 25% of the surface area. This indicates crevassing has decreased by 50% since 1972. This glacier remains large and vigorous in its flow. The decrease in crevassing indicates some deceleration. The crevasse pattern is caused by the thin ice, for the size of the glacier, passing over small bedrock knobs. The red arrows in the last image indicate the deglaciated bedrock knobs and the blue arrows the pattern of crevassing going over the knob. This is a 2009 picture, the terminus is quite thin indicating retreat is ongoing. The retreat of this glacier follows that of Quien Sabe Glacier over the ridge to the south and McAllister Glacier 10 km to the west. The glacier is like all 47 glaciers we have observed in the North Cascades retreating.

boston 2005
2005 image

boston glacier 06
2006 Google earth image

boston glacier 2006
2006 image taken by Leor Pantilat

North Cascade Glacier Climate Project 2014 Field Season (31st Annual) Preliminary Results

The 2014 Glacier Field season was our 31st consecutive year working on North Cascade glaciers. After a late winter surge of snowfall, the North Cascades had a slightly above average snowpack as the melt season began in early May. The warm, dry summer to date, could end up being the warmest for the region, currently 2013 was the warmest melt season. The result is glacier melt has been high overall. In the field we measured the mass balance, terminus position, surface elevation and runoff from North Cascade glaciers. This includes assessment of annual retained snow layer thickness in crevasses and overall crevasse depth.

We first examined the Easton Glacier on the south side of Mount Baker, which has now retreated 370 m since 1990. The glacier has retreated 55 m in the last two years. The most interesting change is that the western toe of the glacier has receded beyond its normal drainage channel, and there is no outlet stream from the west side of the glacier. Snowpack below 2100 m was much below normal including on the bench at 1900 m below the main icefall. Above this main icefall snowpack was closer to normal. Snowpack average 4.5 m at 2500 m, assessed in numerous crevasses. The ongoing warm conditions will continue to reduce the snowpack more than the average summer. With typical late summer conditions mass balance will be -1.1 m on Easton Glacier. The Deming Glacier debris cover has now spread across the entire terminus, retreat from 1985 to 2014 is 480 m. The snowline was at 2075 m in early August in the main icefall, which is 100 m higher than normal.
Breakfast at camp below Easton Glacier

crevase depth
Jill Pelto assessing the depth of crevasses on Easton Glacier, her sixth year working on glaciers.

crevasse examination
Determination of annual retained snowpack depth using crevasse stratigraphy.

crevasse measure
More snowpack assessment by Ben Pelto and Justin Wright.

Ashley Edwards descending Easton Glacier lower icefall

melviewMelanie Gajewski visually examining the Easton Glacier profile.

icefall panorama
Mauri Pelto on a serac in Easton Glacier icefall, 31st year working on these glaciers.

The next stop was Helitrope Glacier on the north side of Mount Baker, where we installed of a stream gage below the Heliotrope Glacier. Oliver Grah and Jezra Beaulieu of the Nooksack Indian Tribe installed the gage while we calibrated runoff and assessed the amount of snowcover on the Heliotrope Glacier, the western extension of the Coleman Glacier, and installed ablation stakes. The rise in the snowline over the rest of the summer will identify the ablation of snowcover. The maximum snowpack on Heliotrope Glacier was less than 3.5 m, which means almost the entire glacier will lose snowpack by the end of September up to the ridge above it. The daily runoff from the Roosevelt-Coleman-Heliotrope system during our observations was an impressive 14 million cubic feet per day.The snowline was quite high on Roosevelt Glacier and Coleman Glacier at 2000 m in mid-August. The retreat of Roosevelt in particular is impressive since my first visit in 1985, a retreat has been 450 m over this interval.
heliotrope camp2
Camp at Heliotrope Glacier.

coleman Justin Wright on the Coleman Glacier

helitrope gage
Oliver Grah installing stream gage below Heliotrope Glacier.jill probing Jill Pelto probing snowpack.

Continued warm dry weather led to records numbers of hikers at Artists Point as we headed out Ptarmigan Ridge on the northeast side of Mount Baker to work on Rainbow Glacier and Sholes Glacier. During our first day the east wind pushed forest fire smoke into the area eliminating views. We surveyed the mountain goat herds as usual seeing three herds and a total of more than 60 different goats. With the high temperatures and forest fire haze the number of iceworms emerging at sunset during our population count was also an all time low. Rainbow Glacier had snowpack that was 1.25 m below normal. With typical late summer conditions mass balance will be -1.5 m on Rainbow Glacier. Sholes Glacier already had 15% blue ice exposed, on August 7th. This had expanded to 25% by August 12th. This rapidly expanded to 50% by August 23rd, note Landsat comparison below. It will be 60% by the end of August and then likely close to 80% loss by the end of the summer. With typical late summer conditions mass balance will be -1.6 m on Sholes Glacier. Remember glaciers in this area need 60% snowcover at the end of the melt season to balance their frozen checkbook. On Sholes Glacier we completed 118 measurements of 2014 snowpack depth via probing in this relatively crevasse free glacier.
mountain goatsA herd of 48 mountain goats.

sholes probing snowpack
Snowpack probing on Sholes Glacier.

sholes overvieew 2014 Looking at Sholes Glacier from outlet where stream gage is installed.

sholes outlet
Sholes Glacier outlet with the clearer surface melt runoff versus the turbid basal meltwater stream.

ashley streamflowAshley Edwards measuring streamflow.

sholes landsat 2014
Landsat 8 iamges from 8/7/2014 and 8/23/2014-red line is boundary of bare blue glacier ice where the 2014 snowpack has been lost.

jill sketch Jill Pelto sketching in camp.

megan sketchMegan Pelto sketching in camp.

penstemon Jill’s field sketch of glacier runoff with Penstemon in foreground.

coffeepotMegan’s field sketch of glacier input to rising sea level.

We then headed to Lower Curtis Glacier, on Shuksan where the rain gods had their turn. That night we had one of the top three heaviest rainstorms I have experienced during my 31 years and 600+ nights camping in the North Cascades. Totals by morning exceeded 4 inches. Rain continued lightly during the day, making for a foggy day on the glacier. The avalanche danger was too high due to the warm temperatures even with the rain to survey the terminus. The main basin of the glacier had limited areas with snowpack over 2.8 m, which is how much is needed in mid-August to survive to the end of the melt season. With typical late summer conditions mass balance will be -1.1 m on Lower Curtis Glacier
The forecast of a one day rain event was now extended to two more days. We hiked up to Blanca Lake in the rain, woke up in the rain, hiked to the glacier in the drizzle and completed our measurements. The rain returned during the hike around the lake to camp. Snowpack was low around the lake, on the trail in and seemingly everywhere but on the glacier. Strong avalanching made this the first glacier even close to average in its snowpack. Snowpack was low in the highest basin of the glacier that is not as heavily avalanche fed. With typical late summer conditions mass balance will be -0.6 m on Columbia Glacier. The warm weather was evident in the temperature of the water being much warmer than usual in the stream ford that is required to reach the glacier.
lower curtis 2014 profile Annual layers of the Lower Curtis Glacier terminus.

ben stream Surface stream assessment, Ben Pelto

wet funBen Pelto in his tenth year working on the glaciers, fording stream in wet weather to access Columbia Glacier.

columbia 2014 snowpackSnowpack on Columbia Glacier limited blue ice.

columbia glacier july 20 2014 Blanca Lake and Columbia Glacier.

On Mount Daniel the first surprise was that Deep Lake had changed from the normal blue to a jade green. This was due to the heavy rain, even east of the crest, the previous three days, which also caused the Cle Elum River to be quite high, though the water was also warm. Having hiked passed this lake each of the last 30 years this is the first time it was not a deep blue color. It will be interesting to see how long it is until the color reverts to normal. We hiked up the Daniels Glacier to the main summit of Mount Daniel, then descended the Lynch Glacier before reascending the Lynch Glacier. Both glaciers had below normal snowpack and considerable blue ice exposure. With typical late summer conditions mass balance will be -1.2 m on Lynch Glacier and -1.1 m on Daniels Glacier. Neither glacier receives much avalanche snow. The following day on Ice Worm Glacier snowpack was above normal on the lower half of this small glacier, clearly because of unusually large amounts of avalanche accumulation. The top half of the glacier had 1-2 m of snowpack that will be lost by mid-September. With typical late summer conditions mass balance will be -0.5 m on Ice Worm Glacier lynch glacier downview
View down the Lynch Glacier.

daniels overview
Daniels Glacier vieww

ice worm glacier Ice Worm Glacier viewed across terminus melt pond

marmot ptarmigan
Marmot near camp.

Overall North Cascade glaciers will lose considerable volume. The volume lost is less on glaciers in the southern portion of the range and those with high percentages of avalanche accumulation.

easton profile
Easton Glacier profile.

easton icefall2
Easton Glacier icefall

icefall exit
Melanie Gajewski and Megan Pelto below icefall.

Chocolate Glacier Retreat, Glacier Peak, Washington

From 1994-1997 we ran a four year project to survey the terminus response of all the glaciers on Glacier Peak, Washington to climate change. This was a century after a climb in the region by C.E. Rusk. Chocolate Glacier is the largest of the east side valley glaciers. The average retreat of Glacier Peak glaciers from the LIA to the 1958 positions was 1640 m. Richard Hubley noted that North Cascade glaciers began to advance in the early 1950s, after 30 years of rapid retreat. The advance was in response to a sharp rise in winter precipitation and a decline in summer temperature beginning in 1944 (Hubley, 1956; Pelto and Hedlund, 2001). All ten glaciers on Glacier Peak advanced. Advances of Glacier Peak glaciers ranged from 15 to 480 m and culminated in 1978 (Pelto and Hedlund, 2001). All Glacier Peak glaciers that advanced during the 1950-1979 period emplaced identifiable maximum advance terminal moraines, that were fresh and easy to recognize in the 1990’s. By 1984, all the Glacier Peak glaciers were again retreating, the North Cascade Glacier Climate Project has monitored this retreat since 1984.chocolate 2005
2005 Glacier Peak east side

glacier tunnel-esker
Cliff Hedlund beneath Vista Glacier during 1994 expedition.

Beginning at 3050 m Chocolate Glacier descends to 1800 m today. When Rusk (1924) first saw this glacier he noted that it presented a dramatic sediment covered front. Immediately above the terminus it was heavily crevassed and quite active, indicating a slow retreat. This glacier which he named Cool Glacier had retreated little from the alpine meadows fringing the south side of the glacier. The terminus had already retreated 400 m up the narrow valley by 1906 from its LIA. A retreat of 1380 m occurred between 1906 and 1946. The retreat was noted to be particularly rapid during the 1920-1940 period by Austin Post. Glacier advance had begun by 1950. An advance from 1946-1955 of more than 200 m occurred (Hubley, 1956). The advance continued up until 1975 totaling 450 m. This was the largest advance of the Glacier Peak glaciers, probably due to the nature of the steep, narrow valley down which the glacier flows from 1960 m to the terminus. The glacier was approximately at this maximum position when mapped in 1984. In the next sequence of images the red line is the mapped 1984 terminus, green is 1998 and blue is 2009. During our visit in 1994 the glacier had retreated 210 m from the moraine it had generated. By 1998 the glacier had retreated 275 m, and was at the based of a steeper slope. By 2009 the glacier had retreated 500 m since 1984, ending at 1925 m, this is still the lowest of the east side glaciers. chocolate 1984
1984 map view

chocolate 1998
1998 Google earth view

Chocolate 2009
2009 Google Earth

Chocolate Glacier remains crevassed and active, but the degree of crevassing has decline from 1998 to 2009 as evidenced by this closeup of the 2000-2200 m region. It is hard to get a good view of this glacier from up close the best vantage is from across the Suiattle River valley, as seen below. chocolate crevasses 1998
1998 Google Earth view

chocolate crevasses 2009
2009 Google earth view

chocolate Glacier 2006
2006 Glacier Peak from the east

chocolate 2007
2007 Glacier Peak from the east

chocolate 2010

Neve Glacier Retreat, North Cascades, Washington

I have had the opportunity to visit the Neve Glacier on eight occasions, it is not easy to get to. In the North Cascades it is one of a handful of glaciers with a large higher elevation accumulation zone, that is not on a volcano. The glacier feeds Diablo Lake, part of the Skagit River hydropower system. The terminus of the glacier in 1975 was in basin that receives considerable avalanche deposition slowing the retreat. In this post we focus on the thinning of the glacier leading to expansion of bedrock exposures at four locations above the former terminus, that by 2011 had led to this low lying basin being dynamically cutoff from the upper glacier. In each image the red letters A-D are located in the same spot, and the purple arrow on the Google Earth images indicates the terminus position. The first image is an aerial view of the glacier from Austin Post, USGS from 1975: at point A there is a quite small exposure of bedrock, at Point B and C there is a good connection of feeder glaciers from the higher slopes to the main valley glacier. At Point D there is continuous glacier cover. This was the case during my first two visits to the glacier in 1985 and 1988, second image. The third image is from 1990 and reflects limted change from 1975 as well, the blue arrows indicate glacier flow.

. By 1996 notable thinning of the glacier was apparent adjacent to Point A, in 2001 and 2002 the thin nature of the ice around the bedrock at Point A is evident. . The accumulation zone of the glacier around Point B and D in 2001 indicates no bedrock exposure at D and a connection of the upper glacier at Point B; however at Point D in 2009 the large new bedrock areas that have resulted from thinning has occurred. A comparison of the Google Earth imagery from 1990, 2006 and 2009 indicate the expanding bedrock at each Point. A closeup of Point A from 2009 has the bedrock delineated with red dots indicating that the left arm of the glacier that formerly encircled Point A, now ends above Point A and that the right hand arm is only 35 m wide and despite the steep slope has no crevassing and is stagnant. At Point B the upper glacier no longer reaches the main trunk. At Point C the connection to the main glacier has decreased by 50% in its width from 140 m to 70 m, and at Point D several large bedrock areas have emerged. In 2013 or 2014 the upper glacier will likely separate from the former terminus region below the Point A bedrock region. The thinning of this glacier is typical of North Cascade glaciers (Pelto, 2007), though the retreat has been unusually small (Pelto, 2010).

Suiattle Glacier Retreat and Outcrop Emergence, North Cascades

C.E. Rusk in 1906 hiked right to the terminus of Suiattle Glacier, which is labelled Lion’s Paw in Rusk (1924). The glacier had retreated 1400 m since its Little Ice Age maximum and based on the lack of reported brush below the glacier, this retreat had occurred primarily in the previous 30 years. By 1940 the glacier had retreated another 900 m back to within 120 m of its current position. Suiattle Glacier retreated more from its LIA maximum than any other glacier in the area, probably due to the low slope of the Suiattle Valley, from 1550-1700 m, down which the glacier had advanced. Rusk, noted the lack of any terminal moraine near the end of this glacier, this was unusual in his experience. In other words typically in this period a terminal moraine was not too distant from the current termini position. This glacier had already retreated so far that the terminal moraine was not only well down valley, but buried by aggrading sediments from the glacial stream. This retreat continued until 1967, below is a 1967 photograph of the glacier from Austin Post (USGS).
Between 1967 and 1979 Suiattle Glacier stopped retreating and began a small advance. Suiattle Glacier advanced 15-20 m during the 1970’s. Our visit in 1988 to the glacier indicated retreat had just begun, and by 1995 the glacier had retreated only 28 m from 1988 to 1995 (top image). The retreat than accelerated with another 150 m of retreat by by our 2002 survey. The terminus remained crevassed steep and convex through 1995 forcing us to the eastern margin to reach the terminus. By 2002 (second and third image) the terminus was no longer that steep or crevassed and we could walk right down the middle. The overall retreat of this glacier as seen in the Google Earth imagery sequence of 1998, 2006, 2009 and 2011 indicate the retreat with the brown line being the 1985 terminus, the green line the 1998 terminus, the orange line the 2006 terminus and the red line the 2009 terminus. Total retreat from the advance moraine of the 1970’s is 270 m. What is a more important reflection of the is glaciers current state is the thinning that is apparent. Outcrops of rock are emerging as the glacier thins even well above the terminus (A-E). The majority of the outcrops are on the eastern side of the glacier. Even after a year of good positive mass balance for the glaciers in 2011, the outcrops remain exposed. The upper portion of the glacier appears robust still. Unlike its counterpart over the glacier gap on its western margin where the west arm of the Whitechuck Glacier melted away.
On Suiattle Glacier in 2002 we undertook a detailed ice worm study, setting up six square meter plots and counting the ice worms. The recorded mean density was 1800 to 2600 ice worms per square meter in 2002. With an area of 2.7 square kilometers, this represents 5-7 BILLION ice worms on this glacier! This is comparable to the earth’s entire human population on just one glacier. Good thing they do not use many natural resources each. This is also the highest population we have identified in the North Cascades. The picture below is from this survey, the quality is tough because they only come out in low light and this was prior to having a digital camera.

McAllister Glacier Retreat, North Cascades

McAllister Glacier is one of the main headwaters glaciers of Thunder Creek feeding into the Skagit River in the North Cascades of Washington. The North Cascade Glacier Climate Project has examined North Cascade glaciers each summer for 28 years and found all 47 that we visit are retreating and six have disappeared. McAllister Glacier is not a glacier we access. This glacier advanced during the 1950-1979 period. This post examines the changes in this glacier since the 1970’s. The terminus of this glacier is very hard to reach, and almost as hard to see except from the air. The glacier has an accumulation zone extending from to 2000 meters in two basins, each basin then descends an icefall to 1600 meters, the terminus tongue than extends down valley to the current terminus at 1300 meters. In the 1975 vertical aerial photograph from Austin Post, USGS the terminus tongue is heavily crevassed, burgundy arrow, and the glacier ends in the middle of a small lake. The terminus at that point outlined in burgundy has pulled back a bit from the advance moraine of 1972 in orange. The southern icefall, on right, is extremely active with dramatic crevassing.. By 1998 the glacier has retreated 170 meters to the north end of the expanding lake and the terminus tongue still has less but significant crevassing. In 1998 were able to observe the glacier from nearby Snowfield Peak, the snowline on the glacier was well above the top of the icefall, first image below. By 2006 the glacier had retreated another 180 meters, the terminus tongue has even less crevassing than in 1998, middle image below. In 2009 (bottom image in sequence) the glacier has retreated another 60 meters, making a total 1975-2009 retreat of 410 meters. This retreat is very similar to the retreat observed on Mount Baker, North Cascade glaciers: Boulder Glacier, and Rainbow Glacier, Mazama Glacieras well as on nearby Boston Glacier. The terminus tongues now has very limited crevassing indicating the reduction in velocity due to less ice being contributed via the icefalls.
1998 Google Earth

2006 Google Earth
2009 Google Earth
A more detailed look at the icefall from 1975, 1998 and 2009 indicate the changes. In 2009 the northern arm looks to almost end at the top of the icefall the southern arm is much reduced in width and crevassing. At the bottom we return to the 1975 view of the icefall when velocity and crevassing was higher transporting a greater ice volume to the valley tongue.

Borealis Glacier separation and retreat

The Borealis Glacier in the North Cascades of Washington, descends the north side of Primus Peak. Unfortunately the peak is not in prime condition. The thinning glacier has separated into two ice masses, the lower section has also developed a new lake since 1995. The USGS map for the glacier indicates the upper and lower glacier connected by two ice tongues (top image). This connection has been severed by 1990 in an aerial photograph from the USGS(second image). At this point no lake exists below the lower glacier. . In 2006 the lower section of the glacier has undergone a rapid retreat of 200 meters since 1990 and a new lake has formed (top image below). By 2009 the lake has expanded as the glacier has retreated and additional 40 meters (second image below).. This glacier viewed from the edge of the terminus lake in 2009 illustrates the stagnant nature of the lower glacier. The lake will continue to expand at the expense of the lower glacier. The upper glacier has been retreating slowly.

Columbia Glacier Past, Present and Future

For the last 27 years the first week of August has found me on the Columbia Glacier in the North Cascades of Washington. Annual visit pictures up to 2008 can be seen at bottom of post.

This is the lowest elevation large glacier in the North Cascades. Columbia Glacier occupies a deep cirque above Blanca Lake and ranging in altitude from 1400 meters to 1700 meters. Kyes, Monte Cristo and Columbia Peak surround the glacier with summits 700 meters above the glacier. The glacier is the beneficiary of heavy orographic lifting over the surrounding peaks, and heavy avalanching off the same peaks. Over the last twenty seven years the annual mass balance measurements indicate the glacier has lost 14 meters of thickness. Given the average thickness of the glacier of close to 75 meters in 1984 this represents a 20% loss in glacier volume. During the same period the glacier has retreated 135 meters, 8% of its length. Most of the loss of volume of this glacier has been through thinning not retreat. The glacier remains thick, but cannot survive current climate, which has left the glacier without any snowpack by the end of the summer in five of the last 10 years. This lack of persistence is the sign of a glacier than cannot survive. We can look at the past of the Milk Lake Glacier near Glacier Peak in 1988, 30 miles northeast of Columbia Glacier, and the present of Milk Lake without the glacier. The green arrow points to the forming lake filled with by both icebergs and the still evident glacier. The upper margin of the glacier is indicated by the red arrow. The lake in 2009 still is a nice jade green from glacier erosion. This lake will slowly become more azure in color as no new glacier sediment is added. In the same respect we can look at the past and present of Columbia Glacier comparing a 1986 and 2010 photograph. The blue arrows indicate moraines that the glacier was in contact with in 1986, and now are 100 meters from the glacier. The green arrow indicates the glacier active ice margin in 1986 and again that same location in 2007 now well off the glacier. The red arrow indicates the same location in terms of GPS measurements, this had been in the midst of the glacier near the top of the first main slope in 1986. In 2007 this location is at the edge of the glacier in a swale.. To look to the future Jill Pelto, (see marvelous destiny blog) my daughter painted the glacier as it was in 2009 (top) and then what the area would like without the glacier in the future, at least 50 years in the future (middle), and Jill at the sketching location (bottom), turned 180 degrees to view Blanca Lake. The lake is colored by the glacier flour from Columbia Glacier to the gorgeous shade of jade. Clearly the area will still be beautiful and we will gain two new alpine lakes with the loss of the glacier. After making over 200 measurements in 2010 we completed a mass balance map of the glacier. This summer we will be back again for the 28th annual checkup.

Banded Glacier a new alpine lake

The Banded Glacier on Mount Logan in the North Cascades of Washington has retreated since 1960 creating a new alpine lake. The glacier has retreated 450 m in from 1960 to the 2006 satellite image expanding the proglacial alpine lake. This glacier is retreating as are all North Cascade glaciers. The 1960 image is from Austin Post (USGS). The 2006 image has a blue dotted line at the 1960 terminus. Note the spread of rock outcrops in the accumulation zone suggesting this glacier will have trouble surviving, a blue arrow indicates the new rock outcrops..The glacier has lost 40% of its area in this 46 year period. The north side (left side in the image) is very short at this point. The new lake has a number of icebergs in it. The number of crevasses has also diminished as the glacier has thinned, become shorter and as a result moves slower. The images below are from 1960, 1998, 2006 and 2009. The retreat from 1998-2009 is 270 meters.banded19600 The slower movement is despite an increase in surface slope as the glacier has retreated from the flatter lake basin area onto the slopes leading to the summit of Mount Logan. This glacier is difficult to view unless you are right in the basin where it is. In 2005 and 2009 this glacier lost almost all of its snowcover, not a good sign for a glacier to survive.

Quien Sabe Glacier Retreat

The Quien Sabe Glacier in the North Cascades of Washington has experienced rapid retreat in the last 20 years. This glacier is the largest in Boston Basin near Cascade Pass, its name translates to “who knows?”, well we all know it is not enjoying recent climate. In the 1960 Austin Post photograph he gave to me in 1994, the glacier was heavily crevassed and advancing. By 1975 the advance had ceased, but little retreat occurred until 1987. This glacier faces south and is fed by avalanching off of Forbidden and Sahale Peak. The glacier retreated 1200 meters from its Little Ice Age maximum (moraine indicated with blue arrows) until 1950. Richard Hubley noted the advance by 1955, the total advance was 55 meters by 1975 (advance moraines noted with orange arrows). We were able to identify the advance moraine in 1985 when it was still quite evident. The smooth bedrock, Granodiorite in the basin, provides little friction for this glacier as it moves over the polished slabs. Today the terminus moraines from 1975 range from 150-250 meters from the current glacier terminus averaging just over 200 meters. For a glacier that averages 700 meters in length this is a significant loss of total area. There are a number of bedrock outcrops that have appeared above the terminus indicating how thin the terminal area is and that retreat is ongoing. . In 2009 the glacier lost almost all of its snowcover an occurrence that has become frequent in the last 18 years. In this August image the glacier is 25% snowcovered. Fortunately 2010 was a better year in terms of snowcover, with more than 50% of the glacier snowcovered at the end of the summer, photograph from Neil Hinckley.
Quien Sabe Glacier viewed from a similar location on the western side of the glacier in 1985 and 2007. The reduction in crevassing, thickness is evident as is the marginal retreat and emerging bedrock.

The Lower Curtis Glacier on Mount Shuksan advanced from 1950-1975 and has retreated 150 meters from 1987-2009. A longitudinal profile up the middle of the glacier indicates that it thinned 30 meters from 1908-1984 and 10 m from 1984-2008. Compare the 1908 image taken by Asahel Curtis (glacier named for him) in 1908 and our annual glacier shot in 2003. The thinning has been as large in the accumulation zone as at the terminus, indicating no point to which this glacier can retreat and achieve equilibrium with the present climate. However, the glacier is quite thick, and will take 50-100 years to melt away. This glacier is oriented to the south and fed by avalanches from the Upper Curtis Glacier and the southwestern flank of Mt. Shuksan. This allows it to survive in a deep cirque at just 5600 feet. Because of its heavy accumulation via avalanching the glacier moves rapidly and is quite crevassed at the terminus. Image below is a 2009 sideview, note the annual dark layers in the ice. The number of crevasses in the nearly flat main basin of the glacier has diminished as the glacier has thinned and slowed over the last 20 years. The glacier lost nearly all of its snowcover in several recent years 2005, 2006 and 2009. In one month we will back on this glacier investigating its mass balance and terminus position. It is a key glacier this year, as the winter was quite warm yet wet, spring was not. Thus, snowpack was much below average below 5000 feet and likely above average above 7000 feet, where the transition will be is the key. In the google earth images below Lower Curtis Glacier is in the left center. The terminus is exposed bare glacier ice and is heavily crevassed. Typically the terminus loses its snowcover in mid-June. Below the terminus there are frequent ice and rock falls, so it is best not to go below the terminus. For our measurements we need to, but we always finish by 9 am. .