THE SUN HOLDS REIGN OVER MELTING SNOWS DURING 2003-Our twentieth field season 

Report of the North Cascade Glacier Climate Project 2003 Field Season
Mauri Pelto, Director (NCGCP), Nichols College, Dudley, MA 01571:
peltoms@nichols.edu:

     The 2003-2003 winter season got off to a slow start, with snowpack remaining well below normal until lat February.  A period of cooler wetter weather than extended well into May raising snowpack at higher elevation sites to near normal levels.  However, once summer began it was long, dry and warm.  Ablation was high and not since 1992 has snowpack been so restricted on North Cascade glaciers.  The field crew included Joe Wood, pursuing a masters degree at Western Washington University and Rick Taylor a high school physical science teacher from Connecticut.  We first hiked to the Columbia Glacier.  There was no snow enroute to Blanca Lake, a bad sign overall, as only in poor years are all snowpatches gone from the trail at the end of July.  The end of the Columbia Glacier as seen below was entirely bare of snow.  Only the avalanchefans on the west side of the glacier had substantial snowpack left.  The terminus was thinning considerably during the summer season, which should increase retreat in the coming years.  This is still a thick glacier that will continue to retreat slowly 3-5 m/year.

    The second destination was Easton Glacier.  No snow  was encountered in the ascent up the Scott Paul Trail or the valley immediately below the glacier.  Ablation stakes had been placed in this glacier in early July and we placed additional stakes in the glacier to be checked at several times later in the summer.  The snowpack melted away entirely below 6200 feet by the 20th of August.  And by the end of September the snowline had risen to 7200 feet.   The Easton Glacier retreated 19 m during this summer season.  Ablation in August alone amounted to 1.6 m.  Ablation measurements completed through the summer season indicated that this glacier released 3.3 billion gallons or water all of it utilized for hydropower.  The crevasses in the ablation zone continue to widen making a formally easily trek up the middle of the glacier a very difficult crevasse maze to get through.


 

Figure 1;  This shows the snowpack over the last 20 years at Lyman Lake as recorded by the USDA snotel program.  The 2003 season is in olive green and has squares.  It is apparent that snowpack was below normal but only slightly at Lyman Lake.

From Easton Glacier we traveled around Mt. Baker to work on the Lower Curtis Glacier on Mt. Shuksan.  This glacier remains very active in it flow.  However, the terminus has continued its retreat at a rate of 5-7 meters/year.  Snowpack was very low in the avalanche fans, indicating how poor the winter was in developing avalanche conditions on the Upper Curtis Glacier.  We saw one mountain goat navigating the steep slopes of Mt. Shuksan below us.

We traversed across to Austin Pass and then out Ptarmigan Ridge to the Rainbow Glacier.  Snowpack was very thin on the Sholes Glacier, which lost all of its snowcover by summers end.  Rainbow Glacier is thinning dramatically above the terminus, but the terminus itself is in a depression that acts as the final runout for avalanches and its retreat rate has declined.  The crevassing has also declined noticeably as the glacier continues to slow down.

We journey next to the Boulder Glacier.  This glacier we visit every five years to survey the terminus change.  It advanced more than any other North Cascade glacier 900 meters between 1950 and 1975, but as we found this summer, the rapid retreat begun in 1980 continues.  The glacier has retreated 430 meters since 1988.  That is 28 meters per year.

We returned to the Easton Glacier and checked are ablation stakes and gave a tour of the lower section of the glacier to water officials from the City of Bellingham.  As the neighboring Deming Glacier is a key water source for the Middle Fork of the Nooksack River and Bellingham.  By measuring the melt rate on the glacier and multiplying by the area of the Deming Glacier the amount of runoff is determined for the glacier.  During the summer of 2003 the Deming Glacier provided 31% of the flow to the river in August and more than 20% during the entire summer period.

The glaciers around Cascade Pass had the poorest snowpack of any region in the North Cascades.  By the end of the summer the Cache Col and Yawning Glaciers were devoid of any snowpack.  This led to the loss of 2 meters of ice thickness from the glaciers which is 5% of the entire volume of these two glaciers down river in one summer.

Our last stop was Mt. Daniels.  The snowpack was poor here and the Daniels Glacier continues its retreat along its long lower margin.  The main terminus is fully separated from the rest of the glacier now.  The Ice Worm Glacier continues to thin but retreat only slowly.  Lynch Glacier had better snowpack than its neighbors on the mountain, but still the third lowest amount in the last twenty years.

Overall the glacier lost an average of 1.5 meters of thickness this summer which is 3-5% of the entire volume of the glaciers.  Not a sustainable rate for these glaciers.  Below is the graph showing glacier mass balances for the twenty years of the program.  This illustrates the 6+ meter loss of water equivalent which equals at least a 7 meter loss in glacier thickness in the twenty years which is a 14-20% loss in glacier volume for the period.