Why some dunes roar like music

Transcript

When sand avalanches down a dune’s steep face, the grains rub, vibrate, and set the dune humming with a low booming note. The dune sings only when the sand is very dry, made of round, similar-sized, silica-rich grains, and often rests above a moister layer that helps trap and amplify the sound. That special layering acts like a natural waveguide, reflecting and strengthening certain frequencies until the dune seems to sing across the desert.