and bybyairing theheir visual observations with what's on the radar, it allows us to o come ta much stronger concnclusion about whwhere the annual l layer is or where a specificic densi change might be that they're looking for in the mass balance process. >> by dragging his gpr sled, named the bumblebee, and using the pits to calibrate it, candela is helping create a much better understanding of this dynamic glacial system. the researchers also map the movement of the ice with gps and 3-d imagery. >> ...successful? >> i think we're very successful. jerking it around. >> ok, s so i grab it, and i moe it around to that. wow.. >> they even get deep under the ice in vast complexes of subglacial caverns to calculate how the glaciers are melting from the bottom up. the huge llewellyn glacier r in canadadas melting fastst, exposing more of itits secrets for researarchers brooke stamper and mira dutschke to discover, using photogrammetry and ice lens measurements. as the 2013 field season on the icefield comes to a close, we make our way northeast and walk off the llewellyn glacier through a dangero