NORTH CASCADE GLACIER RETREAT
 


 

Mauri S. Pelto, Director  Founded 1983
     Nichols College, Dudley, MA    mspelto@nichols.edu

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Updated 3/11/2011

Terminus Behavior

North Cascade glacier retreat is rapid and ubiquitous.  All 47 monitored glaciers are currently undergoing a significant retreat or have disappeared in the case of six of them  Lyall Glacier, Lewis Glacier, Spider Glacier, Milk Lake Glacier, Mt. David Glacier and North Arm Whitechuck Glacier have disappeared (Right).  This retreat on eight Mount Baker glaciers from 1984-2005, each was advancing in 1975, averages 340 m.   The data indicate broad regional continuity in glacial response to climate.    The rate of retreat increased from 1992-1998 and again in 2003-2006.  On each glacier the terminus location is surveyed from a fixed benchmark location beyond the terminus.  The terminus is also located utilizing differential GPS to determine location to within a few feet.  Glaciers are not just retreating at the terminus, lateral and even retreat at the head of the glacier can also be substantial.

 

Advancing

Stationary

Retreating

Gone

North Cascades

 

 

 

 

1967

19

8

20

0

1974

20

5

22

0

1985

5

10

32

0

1995

0

0

47

2

2007

0

0

41

6

The disconnected small snow patches of the former Spider Glacier in 2007.

Terminus Data

Glacier Disequilibrium:

There is no evidence that North Cascade glaciers are close to equilibrium.  Mass balance has continued to decline even as the glaciers have retreated.  Their ongoing  thinning indicates that all of the glaciers will continue to retreat in the foreseeable future.  In cases where the thinning is substantial along the entire length of the glacier, even in the accumulation zone than no point of equilibrium can be achieved with present climate and the glacier is unlikely to survive.  This is the case on 9 of 12 glaciers where we have mapped the changes in glacier thickness. Foss Glacier, Mount Hinman and Ice Worm Glacier, Mount Daniels are two examples of endangered glaciers.  The primary glaciers of Mount Baker can all retreat to a new point of equilibrium with current climate. Glaciers that will not survive are identified by the retreat of their margins in their upper regions and new rock outcrops in these areas.  This is supposed to be the accumulation zone and thinning should not be occurring.

 


Terminus of Lyman Glacier.  The lake beyond the glacier began to form in 1940.  The terminus has retreated at a rate of 10 m/a since then.  The area where vegetation becomes dominant is the 1890 trimline.  .


Above former Lyall glacier from Google Earth Image of 2005.

At left Honeycomb Glacier in 1977 (Bill Arundell) and  2006 (Lowell Skoog)
 

Columbia Glacier retreat 1984-2006. Easton Glacier retreat 1985-2003.
Boulder Glacier 1993 Boulder Glacier 2003
Lower Curtis Glacier retreat 1985-2003. Lower Curtis Glacier 1908.  (Asahel Curtis Photograph)

This rapid glacier retreat is evident in the reduced stream flow and increased runoff in the area. In the long run glacial retreat causes less runoff to be available which in turn reduces overall water supply. The recent change in climate is directly effecting the glaciers.  The increases in temperature is causing the retreat of the glaciers to increase at a rate that is effecting the streamflow and runoff in the area.  Data of specific retreat is shown below.   The Lewis Glacier at left melted completely in 1993

Different glaciers respond at various rates depending on their characteristics. This is evident in the differing behavior during this century.  With three different glacier types.1) Retreat from the Little Ice Age (LIA) to approximately 1950 followed by a period of advance from 1950-1976, and then retreat since 1976. 2) Rapid retreat from the LIA to approximately 1950, slow retreat or equilibrium from 1950-1976, and moderate to rapid retreat since 1976.  3) Continuous retreat from the LIA to the present.   These types reflect different physical characteristics.  Regardless of type all glaciers are now retreating.  Detailed research report

A glacier that illustrates the glacier retreat is the Lynch Glacier below which initially fills the lake basin in 1978, then retreats to the margin of the lake in 1985 and then retreats upslope from the lake by 1994.

Other glaciers have fared even worse Whitechuck Glacier in  particular has suffered, with the north half of the glacier completely melting away (see Death of a glacier).  Variations in other specific glaciers are seen in the Changes in glaciers through time photographic series.  


Left, Lynch Glacier in 1978 when it still filled Pea Soup Lake.  Above, Lynch Glacier in 1985 having just retreated from the lake.  The dots indicate measurement sites for mass balance.  Below, Lynch Glacier in 1998 having retreated fully from Pea Soup Lake.

The Foss Glacier at left in 2005 with the 1985 margin illustrated in red.  This glacier has lost half of its area in just 20 years, below is Foss Glacier in 1988

Glacier Changes through Time photographic Series

TYPE 1

1850-1950

1950-1979

1980-2006

Latitude

Longitude

Mazama

-2350

450

-460

48 48

121 48

Rainbow

-1370

512

-410

48 48

121 46

Easton

-2420

608

-275

48 45

121 50

Squak

-2500

305

-265

48 45

121 49

Talum

-1975

275

-290

48 45

121 48

Boulder

-2560

743

-475

48 46

121 47

Coleman -2500 756 -440 48 48 121 50
Deming -2200 628 -350 48 45 121 51

Ermine

-1800

170

-330

48 09

121 07

Dusty

-1800

280

-350

48 07

121 06

N. Guardian

-1550

160

-17 5

48 07

121 05

Kennedy

-1700

330

-350

48 07

121 07

Scimitar

-1600

350

-320

48 08

121 07

Ptarmigan

-1050

75

-190

48 09

121 08

Vista

-1900

105

-160

48 09

121 07

Quien Sabe

-1250

55

-156

48 30

121 03

Lower Curtis

-645

225

-184

48 50

121 37

Ladder Creek

-1230

105

-165

48 39

121 09

Sulphide

-1775

210

-135

48 49

121 07

TYPE 2

 

 

 

 

 

Cache Col

-360

-25

-72

48 22

121 03

Columbia

-560

-15

-90

47 56

121 21

Watson

-320

-21

-102

48 41

121 06

Neve

-720

-25

-330

48 38

121 07

Sahale

-260

-12

-62

48 49

121 02

Sholes

-1170

-57

-85

48 49

121 46

Yawning

-310

35

-75

48 27

121 02

Lynch

-60

-390

-123

47 34

121 11

Ice Worm

-925

0

-38

47 34

121 10

Daniels

-960

-20

-410

47 34

121 10

White River

-780

-140

-185

48 03

121 05

Suiattle

-2400

15

-175

48 04

121 05

TYPE 3

 

 

 

 

 

Lewis

-65

-80

Gone

         48 31

       120 48 

Colonial

-230

-81

-145

48 40

121 08

Lyman

-1020

-408

-76

48 10

120 54

Foss

-975

-86

-402

47 34

121 12

Hinman

-410

-300

-243

47 35

121 14

S. Cascade

-1800

-350

-160

48 21

121 03

White Chuck

-1300

-330

-230

48 04

121 07

Honeycomb

-1750

-290

-430

48 04

121 04

Milk Lake

-400

-190

Gone

48 10

121 11

Lyall -370 -60 Gone    

 Table 2.  Retreat in meters of North Cascade glaciers since the LIAM.

 


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