Geographic, hydrological, and climatic significance of rock glaciers in the Great Basin, USA

ABSTRACT

We present the first comprehensive inventory and analysis of rock glaciers in the hydrographic Great Basin (GB), United States, documenting 842 features (mean 9.9 ha; range 0.1–201 ha) across thirty-two mountain ranges. These encompassed 8° latitude (from 36.5°N to 44.3°N) and 11° longitude (from −110.7°W to −121.4°W), and composed 83.1 km², or 1.1 percent, of the cumulative area above the lowest rock glacier elevation. Forty-five percent of the features were mapped as intact (containing ice) and occurred across sixteen mountain ranges. Rock glaciers conservatively contained cumulative water volume of 0.8924 km³. We also mapped 237 persistent ice fields from thirteen GB ranges. Ice-field water equivalent was 0.0653 km³; rock glaciers contributed 93 percent of the total water volume (rock glacier:icefield ratio, 14:1). Rock glaciers occurred on northerly aspects at high elevations (mean, 3,196 m) and had a mean annual air temperature of 1.7°C (range, 1.3–3.3°C). Contributions of water from rock-glacier springs and groundwater have not been included in GB hydrologic assessments, nor have rock glaciers been evaluated for their roles in supporting cold-adapted aquatic fauna and promoting vegetation communities and habitat for alpine terrestrial species. Rock glaciers provide hydrologic and ecologic refugia previously unrecognized in the GB with respect to warming future climates.

KEYWORDS:

• Rock glaciers
• glaciers
• permanent ice fields
• Great Basin
• hydrology
• climate refugia

Acknowledgments

The authors thank Doug Clark (Western Washington University), Andrew Fountain (Portland State University), Greg Stock (Yosemite National Park), and Wally Woolfenden (U.S. Forest Service, retired) for helpful discussions about rock glaciers over many years. We also thank Diane Delany for rendering the figures and Chrissy Howell (U.S. Forest Service) for reviewing the draft manuscript. We especially thank Robert Anderson and an anonymous reviewer for valuable critique of the submitted manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the U.S. Forest Service [Operating Funds].