The study looked at how snow density varies in the Pyrenees Mountains in Spain. Researchers compared two methods to measure snow density: one that takes a core sample and weighs it, and another that uses a wedge cutter to estimate density at different depths. They found that snow density is not consistent and changes at lower elevations when the snow is melting. In January, the snow was melting at lower elevations, but in April, those areas were still denser.