salvatore candela is using a powerful ground-penetrating radar, or gpr as it's known, to get information from the vast areas between snow pits using the pits themselves as a reference for his readings. >> the digging of pits and using ground-penetrating radar really ties well together. since i'm imaging what's in the ground and they're actually digging in the area i'm imaging, they compliment each other in that if i have a question about what i'm seeing on the radar, i can go jump in a 5-meter-deep hole and actually see what is there. and by pairing their visual observations with what's on the radar, it allows us to come to a much stronger conclusion about where the annual layer is or where a specific density 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 aroun