Mark Fahnestock received a B.S. in Geology from the University of Rochester in 1984 and a doctorate in Geology from the California Institute of Technology in 1991. Since that time he has worked as a glaciologist investigating ice flow mechanics and surface conditions on the large ice sheets. After studying Alaskan glaciers as a graduate student, he moved to NASA Goddard Space Flight Center as a post doc investigating surface conditions and ice flow in Greenland and Antarctica. He took a position at the University of Maryland in 1995, working as an Assistant Research Scientist in a cooperative center for Earth system science (now the Earth System Science Interdisciplinary Center). He started at the University of New Hampshire in May 2002.

His research covers many aspects of the role of land-based ice in the Earth system. Results from work with numerous collaborators have included the recognition of a large ice stream in NE Greenland and of the rapid basal melting likely responsible for this rapid ice flow; the first high-resolution radar mosaic of an ice sheet, illustrating both flow features and firn conditions on a large scale; development of a relationship between surface melting and the failure of ice shelves on the Antarctic Peninsula; contributions to the use of INSAR for mapping ice flow velocity and surface topography; techniques for mapping detailed topography from visible-band satellite imagery; the recent history of ice flow variations on the Ross Ice Shelf mapped from enhanced imagery; and work on the controls on rapid ice flow in Antarctica and Greenland. He has also contributed to work on measuring ice discharge in Greenland, and has participated in two Antarctic and four Greenland field excursions. His recent interests focus on the controls underlying rapid ice flow and on atmospheric interactions that determine surface conditions on the large ice sheets. The primary tools for this work are satellite-derived and surface observations and interactions with ice sheet modelers.

Recent community service includes sitting on the Alaska SAR Facility Users Group, an NRC committee to advise NASA about Polar Geophysical Data Sets, the Radarsat Antarctic Mapping Project Scientific Advisory Group, the scientific steering committee for NSF ARCSS Arctic-CHAMP (pan-Arctic Community-wide Hydrological Analysis and Monitoring Program) and serving as an Associate Editor for JGR Atmospheres.