Tenderfoot Glacier, BC Fragmentation Accelerates

The glaciers of Tenderfoot Mountain in 1987 and 2022 Landsat images illustrating the decline in area and fragmentation. Tenderfoot Glacier B-C has lost more than 70% of its area and fragmented. Glacier D and E have experienced recession along their broad lower margins. Glacier F has disappeared

Tenderfoot Mountain has an array of glaciers on its flanks that have been rapidly losing area and fragmenting. One of these is Tenderfoot Glacier (B-C) that feeds into the Lardeau River in the Kootenay Lake Watershed. The glacier filled a north facing basin with an area of km² in the 1980’s topographic map of the area. This is a region where glaciers are struggling. Bevington and Menounos (2021) inventory of glaciers in Western Canada identified an increase rate of loss in this Southern Interior Range from 6.6 km²/year during the 1984-2010 interval to 22.1 km² per year from 2011-2020. They identified for the region that 14,329 glaciers larger than 0.05 km² existed in 1985, of these 13,270 glaciers larger than this threshold remained by 2020, this represents an 8% decline in the number of glaciers. They also identified an +300% increase in fragmentation of glaciers. Here we examine a sequence of Landsat images from 1987-2022 to illustrate the changes in the Tenderfoot Mountain region that and suppliment with a Sentinel 2022 false color satellite image.

In the National Topographic map the area of Tenderfoot Glacier had an area of 1.8 km² with the eastern tributary C feeding the main glacier (B). By 1987 the eastern Tributary (C) is nearly disconnected from Point B. There is a small cirque glacier at Point F. The glacier at Poit A is 0.6 km². In 1987 the combined area of the slope glaciers (D and E) is 5.0 km². In 1998 the Tenderfoot Glacier has not retained any snowcover illustrating why this glacier is more prone to both fragmentation and disappearing. By 2015 Point A glacier is beginning to fragment as well. By 2022 the Tenderfoot Glacier has three fragments with a combined area of 0.5 km², a 70% loss in area since 1987. The glacier at Point A has declined to 0.3 km². The glacier at Point F is gone. The combined area of Glacier D and E had declined to 3.4 km² a 30% decline. Tenderfoot Glacier did not retain any snowcover in 2021 or 2022, illustrating that it cannot survive even present climate. The Lardeau River is known Kokanee salmon . The Kokanee salmon population collapsed in Kootenay Lake after 2014 from 1 million to ~12,000 in 2017, rebounding somewhat to 90,000 in 2020 before declining again to 24,000 in fall 2021 (Nelson Daily, 2021).

Kokanee Glacier is another example of a struggling glacier in the region that Ben Pelto has monitored since 2014, too often with little snowcover by the end of summer, see below.

Tenderfoot Glacier in Canadian Topographic map and October 1, 2022 false color Sentinel image. Point B and C indicate two segments of the Tenderfoot Glacier that have now fragmented.

Kokanee Glacier in 2021 stripped bare of snowcover, with a relatively dirty surface (Ben Pelto-image).

Bonnet Glacier, Alberta Displays Symptoms Indicative it Cannot Survive

On September 21, 2021April 22, 2024 By mspeltoIn alberta glacier retreat

Bonnet Glacier in Sentinel 2 images indicating the emergence of bedrock due to thinning in the former accumulation zone, Point A. Note the lack of retained snowcover in both years with at least a month left in the melt season.

Bonnet Glacier, Alberta drains north from Bonnet Peak in the Sawback Range 30 km east of the Rocky Mountain Crest. It is at the headwaters of Douglas Creek that feeds into the Red Deer River. In 2017 we reported on the formation of new alpine lakes and the 900 m retreat of the glacier, 20% of its length, from 1987-2016 (Pelto, 2017). Here we examine changes from 1987-2021, including developments in the accumulation zone that provide a future forecast. An inventory 0f glaciers in the Canadian Rockies indicated area loss of 15% from 1985 to 2005 (Bolch et al, 2010), with Alberta glaciers losing area at a higher rate. Tennant et al (2012) noted that from 1919-2006 the glaciers in the central and southern Canadian Rocky Mountains lost 40% of their area. Of the 523 glaciers they observed 17 disappeared and 124 separated. Columbia Icefield, 125km northwest, lost 23 % of its area from 1919-2009 (Tennant and Menounos, 2013).

In 1987 and 1990 the accumulation zone is limited to upper periphery of Bonnet Glacier. In 2015 and 2016 the accumulation zone is restricted to the northeastern periphery. This is indicative of a glacier without a significant persistent accumulation zone. The consistent mass loss is driving the retreat and glacier thinning. In 2018 in the midst of what had been the accumulation zone a small area of bedrock has emerged at Point A. By 2021 this area has expanded substantially with the two bedrock areas poised to merge soon. This thinning in the midst of the former accumulation zone is indicative of a glacier that cannot survive (Pelto, 2010). In 2015, 2018 and 2021 the accumulation area ratio was between 10-15%, a value that typically results in glacier annual mass balance of more than -2 m. The area of main proglacial expanded 50% from 2016 to 2021 to 0.33 square kilometers.

Bonnet Glacier in Landsat images from 1987, 2016 and 2021 indicating retreat. Red arrows indicate 1987 margin, yellow arrows 2016 and the green arrow 2021. Point A indicates the emerging bedrock.

Bonnet Glacier in Landsat images from 1990, 2015 and 2021 indicating retreat. Purple arrows indicate lakes that have formed due to retreat. Point A indicates the emerging bedrock.

Chaba Glacier, Alberta Retreat and Icefall Separation

On January 2, 2019April 25, 2024 By mspeltoIn alberta glacier retreat

Chaba Glacier in 1986 and 2018 Landsat images. Red arrow is 1986 terminus location, yellow arrow 2018 terminus location, pink arrows bedrock steps in icefall area, orange arrow, adjacent glacier and purple dots the snowline.

Chaba Glacier is a valley glacier descending from the Chaba-Clemenceau Icefield ending in the headwaters regions of the Athabasca River in Alberta. Jiskoot et al (2009) examined the behavior of the Clemenceau Chaba Icefield and found that from the mid 1980’s to 2001 the Clemenceau Icefield glaciers had lost 42 square kilometers, or 14% of their area. During this same period terminus retreat averaged 21 meters per year on the glaciers. A short distance to the southeast is the better known Columbia Icefield. Tennant and Menounos (2013) examined changes in the Columbia Icefield 1919-2009 and found a mean retreat of 1150 m and mean thinning of 49 m for glaciers of the icefield, with the fastest rate of loss from 2000-2009. Here we examine the changes of Chaba Glacier from 1986-2018 using Landsat images.

Chaba Glacier has a substantial accumulation zone above 2600 m in the upper basin, the glacier then flows down an icefall from 2600 m to 2000m where it levels off in a lower slope valley tongue. In 1986 Chaba Glacier terminated in a 200 m wide proglacial lake at 1600 m, red arrow. The valley tongue below the icefall was 3.5 km long. The icefall featured one exposure of rock at the pink arrow on the right. The snowline in 1986 is at ~2500 m. The orange arrow indicates a separate glacier that flows down an icefall into the valley below and almost connects with Chaba Glacier. In 1988 the snowline is lower at ~2450 m the proglacial lake. In 1998 the glacier has retreated 200 m, leading to lake expansion. The snowline is at ~2550 m and only the upper bedrock rib is evident in the icefall, pink arrow. By 2016 the proglacial lake has doubled in size. The adjacent glacier that had terminated at the orange arrow, no longer descends below the icefall into the valley. The lower bedrock rib in the icefall is now evident, right pink arrow. The snowline is above ~2600 m, with a month left in the melt season. JuSt across the divide in the Columbia River Basin, measurements by Ben Pelto of UNBC, indicated negative mass balance from 2014-2018 on glaciers in the northern portion of the basin closer to Chaba Glacier. In 2018 the proglacial lake is 900 m across and the glacier no longer terminates in the lake. This Aug. 20 2018 image indicates the snowline is at ~2650 m. The developing step in the icefall, right pink arrow at 2200 m, indicates a lack of strong flow through the icefall to the valley tongue, this will accelerate downwasting of the valley tongue. Retreat from 1986-2018 is ~900 m. The valley tongue has narrowed at its 1986 halfway point, from the icefall to the terminus, from 700 m to 400 m. Chaba Glacier has experienced similar retreat to the adjacent Apex Glacier that experienced a retreat of 800 m from 1986-2010. Cummins Glacier retreated 500 m from 1986-2015, but also fragmented from adjacent glaciers. A short distance southeast, Columbia Glacier an outlet of Columbia Icefield retreated 3000 m from 1986-2015> the rapid rate of retreat is more than three times as fast relative to the Chaba, due to mass loss through ice calving in the large proglacial lake at the terminus.

Chaba Glacier in 1998 and 2016 Landsat images. Red arrow is 1986 terminus location, yellow arrow 2018 terminus location, pink arrows bedrock steps in icefall area, orange arrow, adjacent glacier and purple dots the snowline.

Canadian Topographic map of the Chaba Glacier area, the accumulation zone=A, icefall=I and valley tongue=V, with flow arrows. The map is from ~1990.

Bonnet Glacier, Alberta Retreat & New Lake Formation

On June 22, 2017April 28, 2024 By mspeltoIn alberta glacier retreat

Bonnet Glacier, Alberta compared in Landsat images from 1987 and 2016. The red arrows mark the 1987 terminus, yellow arrows are the 2016 terminus location and the orange arrow notes a separate glacier that has disappeared.

Bonnet Glacier is at the headwaters of Douglas Creek that feeds into the Red Deer River. The glacier drains north from Bonnet Peak in the Sawback Range 30 km east of the crest of the Rocky Mountains and 40 km north of Banff. Here we examine changes in this glacier from 1987 to 2016, a period when retreat has led to the formation of new alpine lakes. An inventory of glaciers in the Canadian Rockies indicate area loss of 15% from 1985 to 2005 (Bolch et al, 2010), with Alberta glaciers losing area at a higher rate. Tennant et al (2012) noted that from 1919-2006 the glaciers in the central and southern Canadian Rocky Mountains lost 40% of their area. Of the 523 glaciers they observed 17 disappeared and 124 separated. The more famous Columbia Icefield, 125km northwest, has lost 23 % of its area from 1919-2009 with ice loss at a minimum during the 1970′s (Tennant and Menounos, 2013).

In 1987 the glacier had two primary termini, red arrows with no evident proglacial lakes at either terminus, red arrows. In 1987 the glacier spilled over a bedrock bench shortly above the terminus in both cases onto a lower bench The glacier has 25% retained snowpack. The orange arrow indicates a small avalanche fed glacier on the east side of the ridge extending north from the glacier. In 1988 the lack of proglacial lakes is noted at the pink arrows. The retained snowpack is again 25% of the glacier area, well short of the 50-60% needed for a glacier to be in equilibrium. In 1990 the snowcovered area is 30% there is a small lake developing at the northern most terminus. In 2015 four new alpine lakes have formed two are separated from the glacier due to retreat, with both active termini also terminating in lakes. The retained snowpack covers 10% of the glacier in 2015. In 2016 snowcover is retained on 20% of the glacier. The glacier has lost 20% of its total area since 1987 with the main terminus retreating 900 m and the secondary terminus 425 m. The 900 m retreat is ~20% of the total glacier length. The lack of retained snowcover even in these August Landsat images indicate a glacier that cannot survive current climate. The retreat is less impressive than on the larger Freshfield Glacier and more in line with retreat and separation seen on Conway Glacier and Fraser Glacier.

Bonnet Glacier, Alberta compared in Landsat images from 1988, 1990 and 2015. The pink arrows mark the locations where lakes developed after 1988 and the orange arrow notes a separate glacier that has disappeared.

Topographic map of the Bonnet Glacier region, Alberta.

Rapid Retreat of Freshfield Glacier, Alberta 1964-2014

On April 9, 2015May 3, 2024 By mspeltoIn alberta glacier retreat, Canada glacier retreat, glacier climate change, Glacier Observations

The Freshfield Glacier is a large glacier southeast of the Columbia Icefield in the Canadian Rockies where recent retreat has exposed a new glacier lake. Today the glacier is 9.8 km long beginning at 3070 meters and ending at 2000 m near the shore of the less than 5 year old lake. This glacier during the Little Ice Age stretched 14.3 km, one of the longest in the entire range extending beyond Freshfield Lake, which was a glacier filled basin. By 1964 the glacier had retreated 1900 meters exposing Freshfield Lake. From 1964-1986 the glacier retreated up this lake basin losing another 1200 meters of length. A comparison of a 1964 photograph from Austin Post and as close to the same view as I could get in Google Earth illustrates the 50 years of retreat. The red line halfway up the lake is the 1964 terminus and the red line at the edge of the lake the terminus location in the topographic map from the 1980’s. Here we examine Landsat images from 1986 to 2014 to further illustrate the changes. Clarke et al (2015) published this week indicates that it is likely that 70% of glacier volume in western Canada will be lost by 2100. In their Figure 4, three of the four scenarios show Freshfield Glacier as surviving to 2100. The adjacent Conway Glacier is also retreating leading to new lake formation.
Freshfield Glacier Google Earth view

1964 image of Freshfield Glacier from Austin Post

Google Earth view of Freshfield Glacier, indicating 1964, 1986 and 2014 terminus positions.

In each image the red arrow indicates the 1986 terminus position, the yellow arrow the 2014 terminus, pink arrow terminus of the eastern portion of the glacier in 2014, and blue dots the snow line on the date of the images. In 1986 the glacier still reaches the western end of Freshfield Lake, the snowline is at 2600 m and the eastern terminus reaches a bedrock step beyond the pink arrow. By 1994 the glacier had retreated to the southwest shore of the now fully formed Freshfield Lake, the snowline was between 2600 and 2700 meters. By 1998 has retreated several hundred meters from the shore of Freshfield Lake into a new basin terminating 600 m from the 1986 terminus location. The snowline is again near 2600 m. The eastern terminus has retreated from the bedrock step.

By 2009 the terminus has retreated from the basin where it terminated in 1998 exposing a new lake that is 300 m long the terminus no longer reaches. The lower 1000 meters of the glacier has a thin width suggesting the glacier terminus ice thickness is also thin. A Google Earth image from 2005 indicates two basins, circular depressions above the terminus that indicate the collapsing and stagnant nature of the lower portion of the glacier. The narrowness of the terminus reach is also evident. By 2013 the glacier has further retreated from the new lake and now ends near the base of the bedrock step. The eastern terminus has retreated to the pink arrow. The snowline in this Sept. 22, 2013 image is at 2700 m and is close to the end of the melt season position, the equilibrium line altitude. In 2014 the terminus has retreated 1700 m from the 1986 position and 2900 m from 1964. This is a rate of approximately 60 m year over a span of 50 years. The glacier remains nearly 50% snowcovered both in 2013 and 2014, indicating a persistent and consistent accumulation zone. The glacier terminus is nearing a bedrock step, with active crevassing on this step. This suggests that the retreat rate should slow in the short term. This glacier remains large and is not in danger of disappearing with present climate. Its behavior mirrors that of the Apex Glacier and Columbia Glacier but is less dramatic in terms of area loss than or the disappearing Helm Glacier. Glaciers in Alberta as a whole are losing a much greater percentage of their area than Freshfield Glacier as reported by Bolch et al (2010).
1986 Landsat image

1994 Landsat image

1998 Landsat image

2009 Landsat image

2005 Google Earth image

2013 Landsat image

2014 Landsat image

Conway Glacier Separation and Retreat, Alberta

On March 16, 2015May 3, 2024 By mspeltoIn alberta glacier retreat, Canada glacier retreat, climate change glacier retreat, Glacier Observations

Conway Glacier drains east from the border with British Columbia into the Howse River. The Howse River joins the Saskatchewan River upstream of the Bighorn Hydropower project, which impounds Lake Abraham and produces 120 MW of power. The map of this area was updated based on 1990 images which indicate Conway Glacier is comprised of two lobes that join near the terminus. An inventory of glaciers in the Canadian Rockies indicate area loss of 15% from 1985 to 2005 (Bolch et al, 2010). The more famous Columbia Icefield, 50 km north, has lost 23 % of its area from 1919-2009 with ice loss at a minimum during the 1970′s (Tennant and Menounos, 2013). Here we examine Landsat imagery from 1986 to 2014 to see the impact of recent climate change.

Map of Conway Glacier area from 1990 image.

In 1986 the two glaciers are still joined, with a surface lateral moraine at their junction, orange dots indicate this narrow surface rock band eroded from the ridge between the two lobes. The yellow arrow in each image indicates the 1986 terminus location of the northern lobe, the red arrow indicates a bedrock step near the southern lobe terminus, green arrow indicates an ice filled basin, and the purple arrow a small tributary joining the main glacier. In 1986 the southern lobe extends 300 meters beyond the bedrock step. By 1994 a small lake is developing at the basin indicated by the green arrow and the northern lobe is reduced in width. Overall less than 40% of the glacier is snowcovered. By 1998 the southern lobe has retreated to the bedrock step and the northern lobe has retreated from the end of the lateral moraine. The glacier again is less than 40% snowcovered. The 2013 image has better resolution thanks to the better Landsat 8 imagery, and has been sharpened using a higher resolution panchromatic image layer by Ben Pelto (Technique will be explained in a future post). The glaciers are no longer joined. The northern lobe has retreated 500-550 m since 1986 and a small lake has formed at the 1986 terminus location, another yellow arrow indicates 2013 terminus. The northern lobe has retreated above the bedrock step, a total retreat of 500-600 m since 1986. Two additional red arrows have been added to indicate 1986 and 2013 terminus location. The small lake at the green arrow has expanded. The tributary connection at the purple arrow is nearly severed. Retained snowpack on the glacier is also limited in area with most of the glacier in 2013 being bare glacier ice. This indicates that snow was not retained in recent previous years either. For a glacier to be in equilibrium it needs more than 50% of its area to be covered by snow at the end of the melt season, not 35% with a few weeks left in the melt season. as in 2013. This glaciers retreat and volume loss mirrors that of the region including Saskatchewan Glacier and Fraser Glacier. Peyto Glacier is the nearest glacier, just 20 km southeast, with a long term mass balance record, which indicates a cumulative loss or over 28 m w.e or 30 m of glacier thickness.

1986 Landsat image

1994 Landsat image

1998 Landsat Image

2013 Landsat image-Pan sharpened by Ben Pelto (Univ. Northern British Columbia)

Southwest Brazeau Icefield Retreat, Alberta

On January 31, 2015January 31, 2015 By mspeltoIn alberta glacier retreat, Canada glacier retreat, glacier climate change, Glacier Observations

The Brazeau Icefield straddles high peaks southeast of Jasper, Alberta. The northern outlet glaciers drain into Maligne Lake and the southern outlet glaciers drain in to Brazeau Lake and the Brazeau River. The Brazeau River flows into Brazeau Reservoir a 355 MW hydropower facility, before joining the Saskatchewan River. An inventory of glaciers in the Canadian Rockies indicate area loss of 15% from 1985 to 2005 (Bolch et al, 2010). The more famous Columbia Icefield to the west has lost 23 % of its area from 1919-2009 with ice loss at a minimum during the 1970’s (Tennant and Menounos, 2013). Here we examine an unnamed outlet glacier at the southwest corner of the Brazeau Icefield from 1995 to 2014 using Landsat imagery.

In 1995 the glacier terminated at the red arrow and was 1900 m long, orange dots mark the upper boundary. The glacier had limited retained snowpack in 1995. The poor clarity is do to forest fire smoke in the region. In 1998 the proglacial lake where the glacier terminates is much clearer, snowpack is again limited, but more extensive than in 1995. In 2002 retreat is evident as the lake is expanding as the glacier retreats. The glacier still ends in the lake and still has limited snowcover. In 2013 the glacier has retreated completely from the lake and snowcover is again limited. The lack of snowcover is persistent in the satellite images which are typically not from the end of the melt season, hence even more snowcover will be lost. Lack of a significant persistent snowcover area indicates a glacier that will not survive (Pelto, 2010). In 2014 the area experienced considerable forest fires, which leads to poor image clarity. The glacier terminus is now significantly separated from the lake and terminates at the yellow arrow. The distance from the yellow to the red arrow represents a 350-400 m retreat in 20 years. The glacier has lost 20% of its length in this period. This retreat is similar to that of Fraser Glacier and more significant given the small size of the glacier than for Saskcatchewan Glacier