Suiattle, White River, Whitechuck and Honeycomb Glaciers North Cascade Range Diminishing Rapidly

USGS Map of the four glacier from 1984, with none of the seven lakes existing.

In 1988 we mapped four glaciers arrayed around the Kololo Peaks just south of Glacier Peak; Honeycomb and White River feeding into Wenatchee Lake watershed, while Whitechuck and Suiatlle fed into the Suiattle River watershed. They had a combined area of 9.2 km². The glaciers had not developed a series of proglacial terminus lakes at that time. We visited each glacier and completed observations in 1995 and 2002 illustrated the formation of six proglacial lakes, with one more developing after that, Lake #7. Further details and image for Whitechuck Glacier . In 2022 the glaciers have retreated away from each of these lakes that had not even begun to form in 1988. The combined area of the four glaciers in 2022 is 5.6 km², a 40% decrease in 34 years.

Whitechuck Glacier in 1988, with the North Branch and South Branch joined and terminating at Lake #5.

Whitechuck Glacier in 2002 with a detached glacier segment at Lake #5.

White River Glacier in 1988 with no lake yet formed at #3 or #4.

White River Glacier terminus with Lake #3 having formed, but still largely snowcovered in early August.

Honeycomb Glacier in 1995 with no lake #1 at the terminus yet.

Honeycomb Glacier in 2002 still in contact with Lake #1.

Kololo Peak glaciers in Sept. 9 2022 Sentinel image.  H=Honeycomb, S=Suiattle, WC=Whitechuck, WR=White River, purple dots are the snowline and Point 1-7 proglacial lakes that formed after 1988 and are no longer in constact with glacier.

In 2022 we had the most extensive melting we have observed after September 1, with active significant melt extending to October 19. The result is striking in Sentinel images from Sept. 7 and Oct. 19 indicating the reduction in snowcovered area, the percentage of a glacier covered by snow is its accumulation area ratio (AAR). On September 9 the AAR of these glaciers was 45% diminishing to 10% by October 19. With negligible retained snowpack on Whitechuck and White River Glacier. Since 1988 Honeycomb Glacier has retreated 950 m, White River Glacier 475 m, Whitechuck Glacier 950 m and Suiattle Glacier 450 m.

Kololo Peak glaciers in Oct. 19, 2022 Sentinel image.  H=Honeycomb, S=Suiattle, WC=Whitechuck, WR=White River, purple dots are the snowline and Point 1-7 proglacial lakes that formed after 1988 and are no longer in constact with glacier.

Honeycomb Glacier Retreat, Washington New Lake Lost Nunatak

Honeycomb Glacier in Google Earth imagery from 1998 and 2016.  The dark orange line is the 1998 margin, we mapped the margin in the field in 1995 and in 2002.  The light orange line is the 2007 margin and the yellow line the 2016 margin. Note crevassing diminished as well. 

Honeycomb Glacier is one of the longest and largest glaciers in the North Cascades.   In 1979 it was 3.9 km long and had an area of 3.5 km2. By 2016 the area had declined to 2,6 km2 and it has retreated 2.6 kilometers since its Little Ice Age Maximum. The glacier was an imposing site to C.E. Rusk who recounted his early 20th century exploration (1924). Like all 47 glaciers observed by the North Cascade Glacier Climate Project it has retreated significantly since 1979. The glacier feeds the headwaters of the Suiattle River, which is also an important salmon stream, for chinook, coho, sockeye and pink salmon (WDFW,2018).

A 1960 photograph taken by Austin Post, USGS shows the glacier ending with no lake at its terminus. The terminus is gentle and has no crevasses, indicating it is relatively stagnant and poised to melt away. The glacier has retreated 1.3 km from its Little Ice Age moraines at this point. In 1967 another Austin Post image indicates a new small lake forming at the terminus.
honeycomb

In 1995 we mapped  the margin of the glacier ending in this lake, where the glacier ended in 1967 and took a photograph back to the glacier. As seen below retreat to this point was 400 m.

honeycomb 1995

A pair of images from Bill Arundell in 1973 and Lowell Skoog in 2006 indicate the scale of the retreat, these images do not show the actual terminus but do show the main nunatak-rock island and how much it has become exposed in the 33 years. This nunatak was hardly evident in 1960, and in a 1940 image of the glacier literally did not yet exist.honeycomb-glacier-1977-2006

The terminus had retreated 400 m from the 1967 position to 1995. In 1987 a new lake began to form at the terminus of the glacier at 1680 m. The glacier is shown ending in this lake in 2002 from both the far end of the lake and the nunatak above the lake, the glacier had retreated 210 m since 1995. In 2006 the glacier retreated from the end of this lake. This is a shallow lake that may eventually be filled in by glacier sediments. The terminus is flat and stagnant ending at 1680 m in the lake. Thus, the rapid retreat will continue, the glacier is still not close to acheiving a post LIA equilibrium. Glacier retreat from 1940-1967 averaged 9 m/year. Retreat was minor between 1967 and 1979. The retreat rate from 1979-1998 was greater at 16 m/year, with a total retreat of 300 m. The retreat than increased from 1998-2016 with the west branch retreating 800 m and the east branch 500 m. The nunatak in the middle of the glacier, which was beneath the ice in 1940 was 90 m above the ice in 2002 when we mapped it.  By 2009 it was no longer a nunatak as the glacier did not merge downstream of the this bedrock knob.

The retreat of this section of the glacier results in a reduced melt area of ~1 km2 in the last 40 years.  This in turn reduces summer glacier runoff as there is no longer snow/ice melting each day under the warm summer conditions. Flow in the Suiattle River in late summer and early fall has declined as a result. In 2002 during mapping of the glacier images from above and below the nunatak indicate the stagnant nature of the ice below the nunatak.

honeycomb new lakehoneycomb2002a

 

Honeycomb Glacier Retreat, New Lake Formation

Honeycomb Glacier is one of the longest and largest glaciers in the North Cascades. It is currently 3.7 km long and has an area of 3.1 km2. It has retreated 2.05 kilometers since its Little Ice Age Maximum. The glacier was an imposing site to C.E. Rusk who recounted his early 20th century exploration (1924). Like all 47 glaciers observed by the North Cascade Glacier Climate Project it has retreated significantly since 1979.

A 1960 photograph taken by Austin Post shows the glacier ending with no lake at its terminus. The terminus is gentle and has no crevasses, indicating it is relatively stagnant and poised to melt away. The glacier has retreated 1.3 km from its Little Ice Age moraines at this point. In 1967 another Austin Post image indicates a new small lake forming at the terminus.
honeycomb In 1995 we visited the margin of this lake, where the glacier ended in 1967 and took a photograph back to the glacier. As seen below retreat to this point was 400 m. honeycomb  1995 A pair of images from Bill Arundell in 1973 and Lowell Skoog in 2006 indicate the scale of the retreat, these images do not show the actual terminus but do show the main nunatak-rock island and how much it has become exposed in the 33 years. This nunatak was hardly evident in 1960, and in a 1940 image of the glacier literally did not yet exist.honeycomb-glacier-1977-2006 The terminus had retreated 400 m from the 1967 position to 1995. In 1987 a new lake began to form at the terminus of the glacier at 1680 m. The glacier is shown ending in this lake in 2002 from both the far end of the lake and the nunatak above the lake, the glacier had retreated 210 m since 1995. In 2006 the glacier retreated from the end of this lake. This is a shallow lake that may eventually be filled in by glacier sediments. The terminus is flat and stagnant ending at 1680 m in the lake. Thus, the rapid retreat will continue, the glacier is still not close to acheiving a post LIA equilibrium. Glacier retreat from 1940-1967 averaged 9 m/year. Retreat was minor between 1967 and 1979. The retreat rate since 1979 has been greater than 38 m/year, with a total retreat of 700 m. The nunatak in the middle of the glacier, which was beneath the ice in 1940 is now 90 m above the ice. The section of the glacier below the nunatak in 2002 is stagnant with no crevasses. honeycomb new lakehoneycomb2002aIndicating this glacier will retreat at least to the base of this rock knob, which will then no longer be a nunatak. A comparison of Google Earth Imagery from 1998 and 2009 illustrate the appearance of numerous new bedrock knobs in the area where there was an icefall in 1995.
survive The upper portion of the glacier has retained its snowcover in recent years indicating the glacier can survive current climate at a much smaller size.honeycomb2002b