Tornadoes, avalanches and weather noise: the infrasound of the elements

Library → Weather, tornadoes, avalanches

The atmosphere is a powerful generator of infrasound. And here it turns from an "interesting fact" into practice: low frequencies are already used to warn of real threats. But the same weather poses the most insidious task for monitoring systems.

A tornado "hums" in advance

Strong thunderstorm vortices radiate infrasound. Alfred Bedard already linked low-frequency acoustics to the vortices of thunderstorms2, and modern measurements revealed the characteristic infrasound of a tornado-producing storm — with the signal appearing before the funnel touched the ground.1 This opens the way to extra minutes of warning where radar lags behind.

Avalanches: already in operation

This is not a laboratory but a working system. Infrasound arrays of 4–5 sensors reliably detect the release of large avalanches at a distance of 3–5 km, in any weather and with zero visibility, and determine the speed of the front.3 4 Commercial installations (for example, IDA) guard dangerous slopes above roads and villages around the clock.5 The same arrays detect approaching lahars and debris flows minutes before impact — already a basis for early warning (Johnson et al., 2023; Marchetti et al., 2019).

An insidious nuisance: front doppelgängers

A passing atmospheric front produces a spatially coherent pressure change across many sensors at once — exactly what an event-detection algorithm is looking for. Telling geophysical infrasound from weather noise is a real scientific problem, not a trifle. It is solved by combining features: the wave's speed and azimuth, its spectrum, its link to meteorological data. In practice the signal is extracted by array correlation (the PMCC method),6 while large analyses of global IMS network data show how to separate incoherent wind noise from spurious coherent signals.7

Did you know?

A tornado's infrasound sometimes appears minutes before the funnel touches the ground.
Avalanche stations work in darkness, fog and blizzards — when both the eyes and radar are helpless.
From the signal delay between an array's sensors, one can even compute the speed of an avalanche front.
Songbirds flee tornadoes in advance: golden-winged warblers evacuated 1–2 days before a tornado outbreak, apparently "hearing" the storm's infrasound from hundreds of kilometres away (Streby et al., 2015).

Why this matters for HERD

Avalanches prove it: cheap local infrasound networks are already saving lives. We are learning to tell a "real event" from weather doppelgängers — and that is exactly the scientific work the network is being built for.

Sources for this article

These sources are part of the full HERD library — 272 vetted sources, with meaning search and topic filters.

peer-reviewed Elbing B.R., Petrin C.E., Van Den Broeke M.S. (2019). Infrasound from a tornado-producing storm. JASA 146(3). pubs.aip.org
peer-reviewed Bedard A.J. (2005). Low-frequency acoustic energy associated with vortices produced by thunderstorms. Mon. Wea. Rev. 133(1). journals.ametsoc.org
peer-reviewed Marchetti E. et al. (2015). Infrasound array detection of snow avalanches. NHESS 15. nhess.copernicus.org
peer-reviewed Mayer S. et al. (2020). Performance of an operational infrasound avalanche detection system. SLF. slf.ch
organization Wyssen Avalanche Control. IDA® Infrasound Detection of Avalanches. wyssenavalanche.com
peer-reviewed Cansi Y. (1995). An automatic seismic event processing for detection and location: the PMCC method. GRL 22(9). doi.org
peer-reviewed Vergoz J. et al. (2022). IMS infrasound data products for atmospheric studies and civilian applications. Earth Syst. Sci. Data 14. essd.copernicus.org
peer-reviewed Streby H.M. et al. (2015). Tornadic storm avoidance behavior in breeding songbirds. Current Biology 25(1). doi.org
peer-reviewed Johnson J.B. et al. (2023). Infrasound detection of approaching lahars. Sci. Rep. 13. doi.org
peer-reviewed Marchetti E. et al. (2019). Infrasound array analysis of debris flow activity and implication for early warning. JGR Earth Surface 124. doi.org
history Abdullah A.J. (1966). The 'musical' sound emitted by a tornado. Monthly Weather Review 94(4), 213-220. journals.ametsoc.org
history Anderson F.J., Freier G.D. (1965). The role of wave motion in a tornado. Journal of Geophysical Research 70(12), 2781-2784. doi.org
review Georges T.M. (1973). Infrasound from convective storms: examining the evidence. Reviews of Geophysics and Space Physics 11(3), 571-594. doi.org
peer-reviewed Jones R.M., Georges T.M. (1976). Infrasound from convective storms. III. Propagation to the ionosphere. Journal of the Acoustical Society of America 59(4), 765-779. doi.org
peer-reviewed Arnold R.T., Bass H.E., Bolen L.N. (1976). Acoustic spectral analysis of three tornadoes. Journal of the Acoustical Society of America 60(3), 584-593. doi.org
peer-reviewed Schecter D.A., Nicholls M.E., Persing J., Bedard A.J., Pielke R.A. (2008). Infrasound emitted by tornado-like vortices: basic theory and a numerical comparison to the acoustic radiation of a single-cell thunderstorm. Journal of the Atmospheric Sciences 65(3), 685-713. doi.org
peer-reviewed Schecter D.A. (2011). A method for diagnosing the sources of infrasound in convective storm simulations. Journal of Applied Meteorology and Climatology 50(12), 2526-2542. doi.org
peer-reviewed Frazier W.G., Talmadge C.L., Park J., Waxler R., Assink J. (2014). Acoustic detection, tracking, and characterization of three tornadoes. Journal of the Acoustical Society of America 135(4), 1742-1751. doi.org
peer-reviewed Waxler R., Frazier W.G., Talmadge C.L., Liang B., Hetzer C., Buchanan H., Audette W.E. (2024). Analysis of infrasound array data from tornadic storms in the southeastern United States. Journal of the Acoustical Society of America 156(3), 1903-1919. doi.org
peer-reviewed Audette W.E., Waxler R., Frazier W.G., Talmadge C.L., Liang B., Hetzer C., Buchanan H. (2025). Comparison of infrasound array data to NEXRAD weather radar for tornadic and non-tornadic storms in the southeastern United States. Journal of the Acoustical Society of America 157(x). doi.org