It's been the subject of a half-century-long debate. But thanks to a new mapping technique, mountain experts have identified the tallest mountain in the US Arctic and uncovered a bit of a surprise as well. Using fodar, a technique he invented to map terrain using airborne photography, glaciologist Matt Nolan created a high-resolution topographic map of the Brooks Range in Alaska, which reveals Mount Isto to be the tallest mountain in the US Arctic, standing 8,975 feet tall, reports Live Science. But though scientists have long thought that Mount Chamberlin, located about 30 miles away, was Isto's biggest competition, Nolan says it actually falls short of another peak. At 8,914 feet, Mount Hubley stands about 16 feet taller than Chamberlin, he explains in Cryosphere.
Nolan was actually using fodar to observe glacier volume change when he realized he was flying over the highest mountains in the US Arctic—only scientists couldn't decide which should wear the crown. That's when Nolan decided to put his technology to the test to find out. As he flew over the Brooks Range in a Cessna 170B equipped with a DSLR camera linked to a GPS unit, skier and mountaineer Kit DesLauriers climbed up and skied down the mountains with her own GPS unit, allowing the pair to chart elevations from the air and ground simultaneously to provide a "measure of accuracy." The resulting maps are accurate to about 8 inches, according to a release. Nolan notes his technology is much like lidar but costs $30,000 rather than $500,000 and can measure coastal erosion, glacier melt, and landslides. "The possibilities are truly unlimited," he says. (An ancient mountain range once fed our oceans.)