Title

Rock Glaciers in the Eastern Cascades, Washington

Presenter Information

Mark Weidenaar

Document Type

Oral Presentation

Location

SURC 140

Start Date

17-5-2012

End Date

17-5-2012

Abstract

Rock glaciers are important landforms in alpine environments, forming debris transport systems, providing indices of past climate, and showing past evolution of landscapes. Additionally, rock glaciers provide habitat for alpine flora and fauna, and serve as water-storage capacity. The eastern portion of Washington State's Cascade Range is a place not previously examined for its rock glaciers, due to its proximity to the Pacific Ocean and its associated marine-influenced climate. The objectives of this study were to determine spatial, activity, and genesis patterns of Eastern Cascade rock glaciers. Using Google Earth, I found 103 rock glaciers in the study area. Rock glaciers are more common further east of the crest and more north, with the largest concentrations occurring east of Lake Chelan (22) and in the Pasayten Wilderness (28); none were found south of the Goat Rocks. Rock glaciers generally face north to northeast. Rock glacier sizes were also correlated to location �" i.e., length and width increase farther east and north. Activity levels rise with elevation, with 31 active rock glaciers above 2000m, 55 inactive between 1600-2200m, and 18 relict below 1900m. Genesis types include 72 debris, 23 gelifluction, and 8 glaciogenic. Glaciogenic-type rock glaciers occur north of 48°N and < 40km from the crest. Gelifluction-types also generally occur north of 48°N, and range from 25-45km east of the crest. Debris-types occur throughout the range and from 20-70km east of the crest. These patterns suggest a strong past and present climatic role in determining Eastern Cascade rock glacier distribution.

Faculty Mentor(s)

Karl Lillquist

Additional Mentoring Department

Geography

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May 17th, 10:20 AM May 17th, 10:40 AM

Rock Glaciers in the Eastern Cascades, Washington

SURC 140

Rock glaciers are important landforms in alpine environments, forming debris transport systems, providing indices of past climate, and showing past evolution of landscapes. Additionally, rock glaciers provide habitat for alpine flora and fauna, and serve as water-storage capacity. The eastern portion of Washington State's Cascade Range is a place not previously examined for its rock glaciers, due to its proximity to the Pacific Ocean and its associated marine-influenced climate. The objectives of this study were to determine spatial, activity, and genesis patterns of Eastern Cascade rock glaciers. Using Google Earth, I found 103 rock glaciers in the study area. Rock glaciers are more common further east of the crest and more north, with the largest concentrations occurring east of Lake Chelan (22) and in the Pasayten Wilderness (28); none were found south of the Goat Rocks. Rock glaciers generally face north to northeast. Rock glacier sizes were also correlated to location �" i.e., length and width increase farther east and north. Activity levels rise with elevation, with 31 active rock glaciers above 2000m, 55 inactive between 1600-2200m, and 18 relict below 1900m. Genesis types include 72 debris, 23 gelifluction, and 8 glaciogenic. Glaciogenic-type rock glaciers occur north of 48°N and < 40km from the crest. Gelifluction-types also generally occur north of 48°N, and range from 25-45km east of the crest. Debris-types occur throughout the range and from 20-70km east of the crest. These patterns suggest a strong past and present climatic role in determining Eastern Cascade rock glacier distribution.