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TitleSelf-leveling ice dam: a mechanism for bidirectional icing development
AuthorMorse, P D; Sladen, W E
Source2018 Joint Meeting of the Canadian Geophysical Union (CGU), Canadian Soil Science Society (CSS), Computational Infrastructure in Geodynamics (CIG), Eastern Section of the Seismological Society of America (ES-SSA) and the Canadian Society for Agricultural and Forest Meteorology (CSAFM), 2018 Joint Meeting abstract booklet; 2018 p. 113
Year2018
Alt SeriesNatural Resources Canada, Contribution Series 20180209
PublisherCanadian Geophysical Union
PublisherCanadian Soil Science Society
PublisherComputational Infrastructure in Geodynamics
PublisherEastern Section of the Seismological Society of America
PublisherCanadian Society for Agricultural and Forest Meteorology
Meeting2018 Joint Meeting of the Canadian Geophysical Union (CGU), Canadian Soil Science Society (CSS), Computational Infrastructure in Geodynamics (CIG), Eastern Section of the Seismological Society of America (ES-SSA) and the Canadian Society for Agricultural and Forest Meteorology (CSAFM); Niagara Falls, ON; CA; June 10-14, 2018
Documentbook
Lang.English
Mediapaper; on-line; digital
File formatpdf
Subjectssurficial geology/geomorphology; hydrogeology; engineering geology; aufeis; flow mechanisms; fluid migration; permafrost; groundwater; snow; icings; geological hazards; ice dams; water redistribution; saturation
ProgramPermafrost, Climate Change Geoscience
Released2018 06 01
AbstractIcings are widespread, poorly understood seasonal features in the northern hemisphere. Their formation has implications for groundwater discharge, water storage, spring freshet diversion, and winter geohazard development. Icing (also known as aufeis, naled, or overflow ice) development occurs in winter where successive overflows of groundwater freeze on the surface and create a sheet-like mass of ice. An icing grows in vertical extent as ice-layers accumulate, and in horizontal extent when new snow cover facilitates development of pipes and channels for water flow. Here we present multiple field observations of bidirectional water redistribution, with horizontal and vertical icing expansion, related to self-leveling ice dams that form in the local snow cover external to the icing. Ice dams with horizontal crests were observed at valley margins. Lateral diversion behind the dam allows groundwater redistribution from the source before overflow occurs. Counterintuitively, ice damming may also facilitate upslope redistribution of water on valley sides; apparent vertical migration of the dam was indicated at several sites by closure of overflow points below the crest, flow from points near or at the crest, and parallel horizontal lineations in the ice. During active overflow events we observed saturated snow behind the dam, level with the crest, and moist snow above the crest. We hypothesize that a portion of the moist snow freezes in contact with cold air, increasing the freeboard of the dam and thereby raising the hydrostatic potential. With subsequent water flow into the snowpack, this mechanism likely allows the dam crest to migrate upslope. These observations imply that water can migrate well beyond the spring outlet to grow the horizontal (and vertical) extent of the icing without the need for new snow. The observations have implications on remotely sensed estimations of icing volume that assume the maximum vertical extent and maximum thickness are related.
Summary(Plain Language Summary, not published)
Natural Resources Canada (NRCan) conducted field work to study winter permafrost and hydrogeological interactions in support of the Permafrost Hydrogeology activity in the Climate Change Geoscience Program. This abstract presents field observations of a processes and subsequently develops a hypothesis to be tested.
GEOSCAN ID311268