Anomaly•Registry
AR-0163

Booming Sand Dunes

Partially explained
Date Described for centuries. Studied scientifically since 1888; the mechanism has been disputed in print since 2007.
Location At least 40 desert dune sites worldwide, including sites in Morocco, Chile, China and California
Category Sounds and Signals

Summary

Some desert dunes give out a loud, low hum when sand avalanches down their steep slip faces: a single note between about 70 and 110 hertz that can last for minutes. The groups that have measured it agree the avalanche makes the sound; they disagree, in print, about what sets the note.

One side says the pitch is fixed by the grains. The other says it is fixed by the layered structure of the dune. Each has published evidence against the other.

one note, 70 to 110 Hz. two published answers to what sets it THE GRAINS Andreotti 2004 Douady et al. 2006 Dagois-Bohy et al. 2012 pitch set by the grains: their size and how fast they slide past each other 2012: sang with no dune THE DUNE Vriend et al. 2007 Hunt and Vriend 2010 Vriend et al. 2015 pitch set by the depth of the loose surface layer: a waveguide note tracks layer depth THE AVALANCHE IS AGREED. THE NOTE IS NOT. 2008 comment: in the 2007 data the measured note does not track the predicted resonance. the 2007 authors replied. the registry found no study that settles it.
Figure Drawn by Anomaly Registry from Andreotti (2004), Douady et al. (2006), Vriend et al. (2007), the 2008 comment by Andreotti, Bonneau and Clément, Hunt and Vriend (2010), Dagois-Bohy et al. (2012) and Vriend et al. (2015). It sets the two published explanations of what fixes the note side by side: the grains, or the dune's loose surface layer.

What is documented

The sound. In a 2010 review, Melany Hunt and Nathalie Vriend of the California Institute of Technology describe dunes with "a remarkable capacity to produce sounds that are comparable with those from a stringed instrument." The sound follows an avalanche of sand down the slip face, the steep lee side of the dune. It occurs at "at least 40 sites around the world", has a dominant frequency between 70 and 110 hertz with higher harmonics, and, depending on the location and time of year, can continue for several minutes, even after the sand has stopped moving. The avalanche can be natural, or set off by people sliding down the slope.

The old accounts. Physicists writing on the subject usually begin with Marco Polo. Vriend's 2010 thesis quotes a translation of his account of desert spirits: "Even in the daytime their voices can sometimes be heard, or there is a clash of arms, a roll of drums or the sound of different musical instruments." The same thesis quotes a Chinese description of the Dunhuang district, dated to around 800, of a "Hill of Sounding Sand".

The first physics. Scientific explanations began in 1888, when Carus-Wilson attributed the sound to friction between grains and Bolton and Julien to a vibrating film of air (Vriend, 2010). In 1966 Ralph Bagnold, author of The Physics of Blown Sand and Desert Dunes, published "The shearing and dilatation of dry sand and the 'singing' mechanism" in the Proceedings of the Royal Society, tying the sound to the shearing of dry grains.

The grain explanation. In 2004 Bruno Andreotti, who had recorded booming at 100 hertz on a barchan dune in Morocco, proposed in Physical Review Letters that the note arises from "wave-particle mode locking" between the moving grains and elastic waves at the sand surface. In 2006 Stéphane Douady and colleagues compared several singing dunes, in Morocco and Chile, with two controlled avalanche experiments, one in the laboratory and one in the field. They concluded that "the frequency of the sound is the frequency of the relative motion of the sand grains", and that "the sound is produced because some moving grains synchronize their motions." In 2012 Simon Dagois-Bohy, Sylvain Courrech du Pont and Douady reported singing avalanches of sieved grains flowing down hard plates in the laboratory, with no dune beneath them, and concluded that a dune is not needed to produce the sound.

The dune explanation. In 2007 Vriend, Hunt and colleagues at Caltech published "Solving the mystery of booming sand dunes" in Geophysical Research Letters, based on field measurements at booming dunes in California. Their paper "challenges earlier reports that the dunes' frequency is a function of average grain size." They argued that the dune acts as a natural waveguide: the booming frequency "is fixed by the depth of the surficial layer of dry loose sand that is sandwiched between two regions of higher compressional body wave velocity." In 2015 Vriend, Hunt and Robert Clayton described booming as sound waves trapped in the dune's surface layer.

The dispute. Within weeks of the paper's publication, Andreotti and his colleagues Bonneau and Clément had posted a comment, published in the same journal in 2008. It states that the model Vriend's group used to analyse its seismic data "does not apply to the surface layer of sand dunes", that the frequency of booming avalanches "is not controlled by any resonance", and that Vriend's own data show no correlation between the measured frequency and the predicted resonant one. Vriend's group published a reply.

Leading explanations

Avalanching grains make the sound (agreed by all the groups cited here; established). Douady and colleagues summarise the older findings: the sound is "not due to the air flow around the dunes but to the motion of an avalanche", and comes from the grains' relative motion rather than from an acoustic excitation of the grains. Vriend's group agrees that the sound is produced by avalanching along the dune surface.

The grains set the pitch (Andreotti; Douady and colleagues; peer-reviewed, contested). On this view the frequency is set by how fast the grains in the flowing layer move past one another, which depends on grain size and gravity. The two groups differ on how the grains lock together: through surface waves, for Andreotti, and through a resonance within the flowing layer, for Douady. Their evidence includes the laboratory avalanches that sang without a dune.

The dune sets the pitch (Vriend, Hunt and colleagues; peer-reviewed, contested). On this view the avalanche is the source, but the dune's layered interior selects and sustains the note, as a waveguide or a resonating body would. Their evidence is field measurements of layer depth, wave speed and frequency at booming dunes, and the observation that the frequency varies with the layering from place to place and season to season.

What the popular version gets wrong

"The wind makes the dunes sing." The sound comes from sand moving down the slip face, after a natural slump or when people slide down the slope. Douady and colleagues state that it is not due to air flowing around the dunes.

"Marco Polo described singing sand dunes." The passage usually cited, in the translation physicists quote, attributes the voices, the clash of arms, the drums and the musical instruments to desert spirits, not to moving sand. Reading it as an account of booming dunes is a later interpretation, though one the physicists who study them make themselves.

"Scientists solved the mystery in 2007." A 2007 paper was titled "Solving the mystery of booming sand dunes". Within weeks a competing group had challenged its model, and in 2012 researchers on the grain side published avalanches that sang with no dune beneath them. There are two published solutions, and they rest on different causes.

Current status

Partially explained. What is settled: booming is produced by avalanching dry sand, as a single note of about 70 to 110 hertz with harmonics, and it needs neither wind nor spirits. What is not settled is what selects and sustains that note: the grains and the rate at which the flowing layer shears, or the structure of the dune beneath. Both explanations are published in peer-reviewed journals, and each side has published evidence against the other. The registry has found no later study, up to September 2026, that resolves the dispute. Measurements of grain size, layering and frequency made together, at the same dunes and across seasons, would be the kind of evidence that could.

Sources

  • Hunt, M. L. and Vriend, N. M. (2010). "Booming Sand Dunes." Annual Review of Earth and Planetary Sciences 38, 281 to 301.
  • Vriend, N. M., Hunt, M. L., Clayton, R. W., Brennen, C. E., Brantley, K. S. and Ruiz-Angulo, A. (2007). "Solving the mystery of booming sand dunes." Geophysical Research Letters 34(16).
  • Andreotti, B., Bonneau, L. and Clément, E. (2008). "Comment on 'Solving the mystery of booming sand dunes' by Nathalie M. Vriend et al." Geophysical Research Letters 35(8). Preprint arXiv:0710.1815.
  • Douady, S., Manning, A., Hersen, P., Elbelrhiti, H., Protière, S., Daerr, A. and Kabbachi, B. (2006). "Song of the Dunes as a Self-Synchronized Instrument." Physical Review Letters 97, 018002. Preprint arXiv:nlin/0412047.
  • Andreotti, B. (2004). "The Song of Dunes as a Wave-Particle Mode Locking." Physical Review Letters 93, 238001.
  • Dagois-Bohy, S., Courrech du Pont, S. and Douady, S. (2012). "Singing-sand avalanches without dunes." Geophysical Research Letters 39(20).
  • Vriend, N. M., Hunt, M. L. and Clayton, R. W. (2015). "Linear and nonlinear wave propagation in booming sand dunes." Physics of Fluids 27(10), 103305.
  • Bagnold, R. A. (1966). "The shearing and dilatation of dry sand and the 'singing' mechanism." Proceedings of the Royal Society of London, Series A 295(1442), 219 to 232.
  • Vriend, N. M. (2010). Booming Sand Dunes. PhD thesis, California Institute of Technology.

Last reviewed: September 2026. Records are provisional. Where the evidence changes, the entry changes. Found an error? Tell us.

Related records
AR-0043 Skyquakes and Mistpouffers Unexplained booms with no seismic source. Some traced, many not. Recorded since the 19th century Partially explained
AR-0046 Whistlers and the Dawn Chorus Whistles on telephone lines in the 1880s were lightning, bent by the magnetosphere. The dawn chorus is made in the magnetosphere itself. Recorded since 1886 Later explained
AR-0032 The Sailing Stones of Racetrack Playa Rocks that move across a dry lakebed on their own. Solved in 2014: thin ice rafts and light wind. Documented from 1948 Later explained
AR-0002 The Wow! Signal A strong narrowband radio signal from Sagittarius, detected once, never repeated. 1977 Unsolved

Advertise on Anomaly Registry

A documentary archive of 175 investigated cases, read slowly and at length by an audience that arrives on purpose. Below are the current delivery figures and what is available to buy.

Figures are rolling daily averages, current as of September 2026. They are restated as the traffic changes rather than left to age quietly, and we are happy to screen-share the underlying Ad Manager and analytics reporting before an insertion order is signed.

Anomaly Registry is a reference archive rather than a feed. Every one of its 175 records is written to a fixed structure, sourced to contemporaneous documents, inquest files, peer-reviewed literature or credible reporting, and each carries a section setting out precisely what the popular version of the story gets wrong. Cases that were later explained and cases that were comprehensively debunked are kept alongside the unsolved ones, because an archive that keeps only its mysteries is not an archive. That editorial position is the reason people stay.

It also explains the shape of the traffic. A session here runs to more than four pages and close to nine minutes, which is several times what a typical content site sees. Readers arrive looking for one case, find the sources laid out, and follow the cross-references into the next record. For an advertiser, the practical consequence is that a banner on this site is in front of a settled, attentive reader for minutes rather than seconds, and it is seen repeatedly across a single visit without ever being the reason someone leaves.

Three placements are available on every page. The leaderboard sits above the masthead and accepts 728x90, 970x90 and 320x50. The in-article unit sits inside the body of the record, where the reader is already stopped, and accepts 728x90, 300x250 and 336x280. The footer unit closes the page and accepts 728x90, 970x90 and 320x50. There are three slots per page and there will not be a fourth: the inventory is deliberately limited so that each impression is worth more than it would be on a page carrying eight.

What we do not run matters as much as what we do. There are no interstitials, no pop-ups, no auto-playing video, no content-recommendation chumboxes, and nothing that reflows the page after the reader has started reading. Ads are served in reserved space so the layout does not jump. This protects viewability for the advertiser as directly as it protects the reading experience, and it is the reason we can quote the session figures above with a straight face.

The editorial environment is unusually safe for a subject area that is often anything but. This site does not publish conspiracy content, it does not promote pseudoscience, and it does not treat a rumour as a finding. Its entire method is to separate what is documented from what has merely been proposed, and to say plainly when a famous mystery has an unglamorous answer. A brand placed here sits next to sourced, corrected, carefully hedged writing rather than next to speculation dressed as news.

The readership is a general-interest one with a research habit: people who read long-form nonfiction, follow science and history coverage, and check citations. In practice the categories that fit well are books and publishing, documentary and streaming, museums and exhibitions, education and online courses, audio and podcasts, consumer technology, outdoor and travel, and financial services. If your product rewards attention and explanation rather than impulse, this is a good room to be in.

Everything is delivered through Google Ad Manager, so you can buy the way you already buy. Direct-sold campaigns can be trafficked as a guaranteed line item with standard reporting on impressions, viewability and click-through. Programmatic demand can reach the same inventory through the open auction or through a preferred deal or private marketplace at a floor we agree in advance. We accept standard IAB display creative and HTML5, and we can accommodate a reasonable third-party ad server or verification tag.

Category sponsorship is available for advertisers who want something more durable than a rotation. The register is organised into seven categories, and a sponsor can take the whole of one, appearing across every record inside it with an acknowledgement in the page furniture. Sponsorship never buys editorial influence: a sponsor cannot commission a record, cannot review one before publication, cannot have a record altered, and cannot have one removed. That rule is not negotiable and it is the thing that keeps the inventory worth buying.

Some categories are declined outright, and it is fairer to say so up front than to discover it after an insertion order. We do not accept adult content, gambling, payday or high-cost short-term credit, cryptocurrency speculation and token sales, dietary supplements making health claims, political advocacy, psychic or clairvoyant services, or anything that reads as a scare advertisement dressed up as an article. Nothing may be styled to look like a record or like part of the editorial page.

Rates depend on placement, volume, whether the buy is run-of-site or targeted to a category, and how long it runs. There is no rate card on this page because a sensible number depends on what you are trying to do, and quoting one in the abstract usually wastes both parties' time. Tell us the campaign, the flight dates and the budget you are working to, and you will get a straight answer including whether we think the fit is wrong.

To start, write to or use the contact form and mark the message for the advertising desk. Include the flight dates, the placements you want, the creative sizes you have ready and any verification requirements, and we will come back with availability and a quote. Media buyers who want the underlying analytics before committing are welcome to ask; we would rather show the reporting than be taken on trust.

Privacy Policy

This policy explains what information Anomaly Registry collects when you visit this website, why it is collected, how it is used, and what choices you have. It applies to anomalyregistry.com and to any subdomain operated by us. It was last updated on the date shown at the end of this policy, and we will revise it if our practices change.

We have designed this site to collect as little personal information as possible. You do not need an account to read anything here. There is no login, no user profile, and no comment system. In the ordinary course of reading the register, you are not asked to identify yourself, and we do not ask you to.

Like virtually every web server, ours produces access logs. These logs record the internet protocol address of the requesting device, the date and time of the request, the page or file requested, the referring page if one was sent, and the browser user agent string. These logs exist for security, abuse prevention, and diagnosing technical faults. They are retained for a limited period and then discarded. We do not use them to build profiles of individual readers.

If you write to us through the contact form, we receive whatever you choose to put into it: typically a name, an email address, and a message. We use that information for the sole purpose of reading and answering your message. Writing to us does not add you to any list, and we do not sell, rent, or trade contact details with anyone.

There is one optional mailing list, and you only join it by asking. If you submit the subscribe form we store the address you gave, the time you submitted it, the IP address it came from, and the exact wording of the consent you agreed to. We keep that record because Canadian anti-spam law expects us to be able to show when and how you asked to hear from us. The list is used to say that records have been published or materially revised, and for nothing else. Every message carries a way to leave, and asking to be removed by email works just as well.

Corrections are a special case, and worth stating plainly. If you write to point out an error in a record, we may act on that correction and revise the entry. We will not publish your name or your email address in connection with a correction unless you explicitly ask us to be credited.

This site is supported by advertising served through Google Ad Manager. Advertising technology providers may set and read cookies or similar identifiers on your device in order to select advertisements, limit how often you see the same advertisement, and measure performance. These identifiers are set by those third parties, not by us, and the data they collect is governed by their own privacy policies rather than this one.

We do not have access to the personal data that advertising partners collect, and we cannot delete it on your behalf. If you wish to limit interest-based advertising, you can adjust the advertising settings offered by Google, use your browser's cookie controls, or use the industry opt-out tools that are available in your region. Details are set out in our Cookie Policy.

We may use privacy-respecting aggregate analytics to understand which records are being read and how people move through the register. Where we do, we configure it to avoid collecting information that identifies individual readers. Aggregate figures tell us that a case page is popular; they do not tell us who read it.

We do not knowingly collect personal information from children. This site is a documentary archive intended for a general adult and older student readership. If you believe a child has sent us personal information through the contact form, write to us and we will delete it.

Depending on where you live, you may have rights over personal data relating to you, including the right to ask what we hold, to ask for a copy, to ask for correction, and to ask for deletion. Because we hold so little, these requests are usually simple to answer. Write to us and we will respond within the period required by the law that applies to you.

Our servers are located in North America, and information sent to this site is processed there. If you are visiting from elsewhere, your request necessarily crosses borders in order to reach us. By using the site you understand that this transfer takes place.

If we change this policy, the revised version will be posted here with a new date. Material changes will be noted plainly rather than buried. Questions about this policy should be sent through the contact page.

Cookie Policy

A cookie is a small text file that a website asks your browser to store, and that your browser sends back on later requests. Similar technologies, including local storage and pixel tags, do comparable work. This policy explains which of these are used on Anomaly Registry, by whom, and what you can do about them.

The registry itself is a reading site. It does not require a cookie to show you a record. We do not set cookies to track you across the internet, and we do not operate a first-party advertising identifier of our own.

Strictly necessary cookies may be set to keep the site secure and functioning, for example to help mitigate automated abuse of the contact form. These are limited in scope and are not used for advertising or profiling.

Advertising cookies are set by Google Ad Manager and by the advertising technology partners that operate within it. Their purposes include selecting which advertisement to show, capping the number of times a given advertisement is repeated, detecting invalid traffic and click fraud, and measuring whether an advertisement was actually seen.

Some of these advertising cookies support interest-based advertising, in which the advertisement you see is influenced by inferences drawn from browsing activity over time and across sites. Whether this occurs depends on your region, your settings, and the choices you have already made with those providers.

We may use aggregate analytics to count page views and understand which records are read. Where an analytics tool is used, we prefer configurations that do not identify individual readers and that do not follow readers across other websites.

We do not embed social media widgets, share buttons, or tracking pixels from social networks. This is a deliberate choice for an archive of this kind, and it removes an entire category of third-party tracking that most content sites carry.

Your browser gives you direct control over cookies. Every major browser can block third-party cookies, delete existing cookies, and clear stored data on exit. Blocking third-party cookies will not prevent you from reading anything on this site, though it may make the advertising you see less relevant.

You can also manage advertising preferences with Google directly through its advertising settings, and through the industry opt-out mechanisms operated in various regions. Because these are operated by third parties, we cannot make the choice on your behalf.

Where the law in your region requires consent before non-essential cookies are set, a consent notice will be shown and your choice will be respected. Withdrawing consent later is possible through the same mechanism.

Advertising partners may change over time. Rather than publish a list that goes stale, we identify the advertising system in use, which is Google Ad Manager, and direct you to Google's own disclosures for the current set of partners operating within it.

If you have a question about cookies on this site that this policy does not answer, write to us through the contact page and we will answer it.

Anomaly Registry is an independent documentary archive. It is published as a work of reference and public interest reporting, and it is supported by advertising. It is not affiliated with, endorsed by, or acting on behalf of any government, university, police service, coroner, scientific institution, or investigative body named in any record.

The register documents real events, including in some cases deaths, criminal investigations, and inquests. Where a record concerns a criminal matter, nothing on this site should be read as an allegation of guilt against any living person. Where an individual has been named in the public record, we report the fact of that naming and its evidentiary standing; we do not accuse.

Records are written from sources. Where a source is a primary document, we say so. Where a claim rests on secondary reporting, we say so. Where sources conflict, we state the conflict rather than quietly choosing a side. Where a widely repeated claim cannot be traced to any source, we say that too, because an untraceable claim is itself a finding.

Every record separates what is documented from what has been proposed. Hypotheses are labelled as hypotheses and attributed to whoever advanced them, together with their standing: peer-reviewed, contested, dismissed, or untested. We do not advance theories of our own.

The registry treats its own entries as provisional. Records carry a review date, and they are revised when the evidence changes. A record you read today may be corrected tomorrow, and that is a feature of the method rather than a defect in it.

Despite this method, errors will occur. If you find one, write to us. Corrections supported by evidence are made promptly, and we would rather be corrected than be consistent.

Scientific and forensic conclusions reported here are the conclusions of the researchers and officials who reached them, not ours. Reporting that a study proposed a mechanism is not an endorsement that the mechanism is correct, and the status assigned to a case reflects the state of the evidence rather than our opinion of it.

Nothing on this site is legal, medical, psychological, financial, or safety advice. Records that touch on medical or psychological matters, including mass psychogenic illness, report the diagnoses reached by clinicians at the time and afterward. They are not a substitute for professional care.

Quotations from sources are used sparingly and for the purposes of reporting, comment, criticism, and review. Copyright in quoted material remains with its owner. If you hold rights in material you believe has been used improperly, contact us and we will address it.

Original text, structure, record numbering, and editorial apparatus on this site are the property of Anomaly Registry. You are welcome to quote briefly and link to us. Wholesale reproduction of records, including reproduction for the purpose of training generative models, is not permitted without written permission.

Outbound links are provided as references. We do not control linked sites and are not responsible for their content, their accuracy, or their handling of your data.

This site is operated from British Columbia, Canada, and these notices are governed by the laws applicable there, without regard to conflict-of-law principles.

Accessibility Statement

Anomaly Registry is built to be usable by as many people as possible, including people who use screen readers, keyboard navigation, magnification, or other assistive technology. We treat accessibility as part of the build rather than as a later remediation.

We aim to meet the Web Content Accessibility Guidelines version 2.1 at level AA. This is a target we work toward continuously rather than a certification we claim to have completed.

The site is written as semantic HTML. Headings describe the real structure of a record, lists are marked up as lists, and the register is a genuine table with proper header cells, so that a screen reader can announce which column a value belongs to.

Every interactive element is reachable and operable by keyboard alone. Focus is visible at all times, and a skip link at the top of each page lets keyboard and screen reader users jump straight to the register without traversing the navigation.

Status is never conveyed by colour alone. Each status carries its written label in text, so a reader who does not perceive the colour difference between "Unsolved" and "Debunked" still receives the distinction.

Text colours have been chosen to meet or exceed the contrast ratios required at level AA against the page background. The typefaces are set at a comfortable reading size with generous line height, and the layout reflows to a single column on small screens without loss of content or function.

The site contains one animated element, an annotation on the home page. It respects the reduced-motion preference set in your operating system, and when that preference is on, the annotation appears without movement.

Text can be resized up to two hundred percent in the browser without breaking the layout or clipping content. Nothing on this site depends on a specific screen orientation.

Advertising is served by a third party. We control where advertisements are placed and label them as advertisements, but we do not control their internal markup, and their accessibility is ultimately determined by the advertiser.

We are developing an audio version of each record. When it is published, it will be an alternative way to receive the same content, not a replacement for the written entry, and the written entry will remain the authoritative version.

Accessibility work is never finished, and parts of this site will fall short of the standard we have set. If you encounter a barrier, we want to know about it. Please tell us what page you were on, what you were trying to do, and what assistive technology you were using.

Write to us through the contact page. We aim to respond within five business days and to fix genuine barriers promptly.

Terms of Use

These terms govern your use of anomalyregistry.com. By using the site you accept them. If you do not accept them, please do not use the site.

Anomaly Registry is offered as a free documentary reference. There is no account, no subscription, and no paywall, and nothing here is offered as a professional service of any kind.

You may read, quote briefly with attribution, link to, and print records for personal, educational, and research use. This is an archive, and it is meant to be used.

You may not reproduce records wholesale, republish the register or substantial parts of it, or scrape the site systematically. In particular, you may not reproduce this content for the purpose of training generative models. Permission for other uses can be requested through the contact page and is often granted.

Original text, the record numbering system, the status taxonomy, the editorial apparatus, and the design of this site are the property of Anomaly Registry. Third-party material quoted or referenced remains the property of its owners.

We work hard to make records accurate, and we correct them when they are not. Even so, the site is provided as it is, without warranty of any kind, express or implied, including any warranty of accuracy, completeness, or fitness for a particular purpose.

Records are provisional by design. A status can change, an identification can be confirmed or overturned, and a leading explanation can be displaced by a better one. Do not treat any record as a final word, and check the review date.

To the fullest extent permitted by law, Anomaly Registry and its operator are not liable for any loss or damage arising from your use of, or reliance on, anything published here.

If you send us a correction, a source, or a suggestion, you grant us permission to use it in the register. You will not be identified in connection with it unless you ask to be credited.

Do not use the contact form to send abuse, threats, spam, or automated submissions. We may block access to anyone who misuses the site or attempts to interfere with its operation.

Outbound links are provided as references and are not endorsements. We are not responsible for the content or conduct of any site we link to.

We may revise these terms. The version published here is the version in force. These terms are governed by the laws of British Columbia, Canada, and any dispute will be heard in the courts of that province.