NORTH CASCADE GLACIER CLIMATE PROJECT  1984-2005

Mauri S. Pelto, Director NCGCP
Nichols College, Dudley, MA 01571 Peltoms@nichols.edu

Snowpack

Snowpack charts

Ice Worms
Mountain Goats New
Ice Worm Charts
Mass Balance

Mass balance Data Set

Terminus Behavior

Terminus Data Set

Glacier Runoff

Glacier runoff  charts

Updated 4/17/06
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INTRODUCTION
         Why study glaciers in the North Cascades of Washington? Glaciers are one of the world’s best climate monitors and are a critical water resource to many populated glaciated regions. This is particularly true in the North Cascades where 725 glaciers yield 200 billion gallons of runoff each summer and where the glaciers have lost 30 % of their area in the last century. Just as important is the magnificent wilderness that is the North Cascades and the biology that inhabits them  This web page documents the principal findings of the North Cascade Glacier Climate Project (NCGCP) which monitors more glaciers than any other program in North America.

NCGCP was founded in 1983 to identify the response of North Cascade glaciers to
regional climate change, particularly changes in mass balance, glacier runoff and terminus behavior. The North Cascades, Washington mountains are host to approximately 725 glaciers. 

Summary Findings

Terminus Behavior

Between 1984 and 2005, NCGCP observed the terminus behavior of  47 glaciers all are currently retreating. Five of the glaciers have melted away completely.  The rate of retreat increased in 1992 and again in 2001. 

Mass Balance 

Annual mass balance surveys on nine glaciers in the North Cascades indicate that North Cascade glaciers have lost an average of 0.5 m of thickness each year from 1984-2005.  This 11-12 m of glacier thickness lost is approximately 20-40 % of the entire volume of North Cascade glaciers, gone in twenty one years.  The trend of consistent negative  balances and glacier thinning of the 1985-1995 period,  has been replaced by wild fluctuations from years of near record accumulation 1997 and 1999 to years of record melt 1998 and 2001, and early season high snowfall for 2002, and exceptionally negative balances in 2003-2005.
       
Glacier Runoff

North Cascade glaciers are an important summer water supply, more during dry summers and in heavily glaciated basins such as Baker Lake.   Glaciers provide 230 billion gallons each summer.  Key changes have been. 

  1. An increase by 16 percent of February-April runoff, despite no change in winter precipitation in the period, thus reflecting increased winter season melting events and rain events instead of snow events. 
  2. An earlier onset of the spring snowmelt season throughout the mountain west.
  3.  Decreased July-September runoff of 35 percent in non-glacier basins, versus 13 percent in glacier basins.

Glacier Disequilibrium

Most North Cascades glaciers are in a state of disequilibrium with the current climate meaning they cannot retreat to a point where equilibrium can be reestablished.  These glaciers will melt away if the current climate continues.


Glacier Biology

There have been several interesting, if moderate, discoveries made during the course of this study.  Taxa were dominated by ice worms, an oligochaete surprising in itself, and by several new species of Collembola, including Isotoma (Myopia) sp., Isotoma (Desoria) sp., and Agrenia sp.  The Agrenia sp. is particularly interesting because it occurred only on the northernmost glaciers, in the Mt. Baker cluster, while the only previously identified species of this genus occur in Arctic environments.  The Myopia sp. is near M. alaskana, previously reported from glacier and non-glacier habitats in Alaska.  These distributions could support a model of distribution based on historic contacts, with the northernmost being the most recent arrivals to this area; or their extinction to the south could be a result of previous stochastically-induced extinctions.  Phylogenetic study is required to solve this question.

Glacier Response Time

  We observe The terminus behavior of 38 North Cascade glaciers during the last century to illustrate three different types of glacier response to climate change: 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.

The initial response times (Ts) of North Cascade glaciers to both a  positive and negative mass balance changes resulting from climate change have been observed on 21 glaciers to be 4-16 years.

Climate Changes

  • That the ablation season temperature has been 1.5F above long term average
  • That winter precipitation was fallen 9% below the long term average from 1984-1995.  Since 1996 winter precipitation has been much higher averaging 7% above average.  But has been variable with 1998 and 2001 being dry years.
  • That the 1990's were more than 0.5 C warmer than any other decade of the century.

Assistants Cliff Hedlund, John Brownlee, Gregg Maddrey, Cliff Mitchell, Joe Drumheller, Richard Campbell, Monica Gowan, David Knoll, Mike Carver, Ann Fitzgerald, Jill Turner, Bill Prater, Scott Townsend, Dan Kaplinski, Don Sayegh, Doxey Kemp, Greg Langkamp, Seth Lemke, Kate Johnson, Kalman Barcsay, Zolt Barcsay, Joel Harper, Lee Scheper, Jarle Seche Jensen, John Maggiore, Mike Hylland, William Long, Bruce Williamson, Paula Hartzell, Ben Barrett, Ed Blanchard, Joe Wood, Richard Taylor, Tim Bartholomaus, Tom Hammond