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A fire’s rumble reveals where it’s burning

A slow grassland burn gave off enough infrasound for sensors to follow its spread

Smoke and flame rise along a ridge of dry, rolling hills under a blue sky.

Researchers tracked this prescribed fire in Idaho using acoustic sensors.

Jake Anderson

By Katherine Kornei

It’s not just eyes on a fire — it’s now ears, too.

A low-intensity grassland fire “hums” loudly enough to be monitored by sound alone, researchers report in the July 16 Geophysical Research Letters. Acoustic sensors deployed near a prescribed Idaho burn picked up the low-frequency rumble it gave off and followed where it was burning — a sign the technique can detect relatively weak fires.