Mars has storms of remarkable variety, from continent-sized dust events that can shroud the entire planet for months to localized whirlwinds, polar snowstorms made of frozen carbon dioxide, and cyclonic vortices tracked by orbiting spacecraft. The Martian atmosphere is thin, roughly one percent the density of Earth’s, yet it drives weather systems that have surprised scientists since the first telescopic observations of planet-wide dust hazes centuries ago. These storms are not mere curiosities: they reshape the surface, strip water from the atmosphere, and pose real engineering challenges for every robotic and future human mission to the planet.
Global Dust Storms
The most dramatic storms on Mars are the planet-encircling dust events. In some years, a regional dust storm feeds on itself, intensifies, and expands until airborne dust covers nearly the entire globe. The 2018 global dust storm is the best-studied example in the modern era. Ground-based telescopes captured a dusty patch roughly 140,000 square kilometers in Acidalia Planitia, centered at about 32°N latitude, on 30 and 31 May 2018. Over the next eight days, the storm expanded southward at around 5 meters per second while simultaneously racing east and west at speeds up to 40 meters per second. By 8 June the dust had reached 55°S latitude and eventually penetrated into the south polar region. This was the first confirmed global dust storm to originate in the northern hemisphere.1Geophysical Research Letters. The Onset and Growth of the 2018 Martian Global Dust Storm
The mechanism behind this explosive growth involves a feedback loop. When a regional storm heats the atmosphere unevenly by absorbing sunlight, it creates temperature contrasts that drive strong winds. Those winds loft more dust, which absorbs more sunlight, which strengthens the circulation further. Modeling of the 2018 event showed that the initial equatorial storm created a temperature gradient that generated powerful eastward winds, rapidly transporting dust around the planet and triggering additional lifting in new areas.2Journal of Geophysical Research: Planets. Simulation of the 2018 Global Dust Storm on Mars Using the NASA Ames Mars GCM: A Multitracer Approach Simulations also show that the intensification of the planet’s north-south atmospheric overturning circulation, called the Hadley circulation, plays a central role in spreading dust to global scales once secondary lifting centers activate.3Journal of Geophysical Research: Planets. Simulation of spontaneous and variable global dust storms with the GFDL Mars GCM
Not every Mars year produces a global dust storm. They occur roughly every few Mars years (a Mars year is about 687 Earth days), and predicting which years will produce one remains an open problem. When they do happen, they last weeks to months. The 2018 storm famously ended NASA’s Opportunity rover mission: so much dust blocked sunlight that the solar-powered rover could not recharge its batteries.
Regional Dust Storms and Their Seasons
Far more common than global events are regional dust storms, which can cover areas ranging from a few hundred to several million square kilometers. A comprehensive database of these storms shows that they tend to start in a handful of preferred locations. In the northern hemisphere, Acidalia, Utopia, and Arcadia Planitiae are hotspots. In the south, the Aonia-Solis-Valles Marineris corridor and the Hellas Basin are primary launch points. Many storms that begin in the north push southward across the equator.4Icarus. The Mars Dust Activity Database (MDAD): A comprehensive statistical study of dust storm sequences
Mars has a pronounced dust storm season. The primary period of activity runs roughly from late northern summer through southern spring, a window loosely comparable to the second half of the Martian year. There is a secondary burst of storm activity in the northern hemisphere later in the year, and another in the southern hemisphere during its own autumn. Researchers studying the climatology of Martian dust activity have proposed dividing each Mars year into six “pseudo-seasons” based on storm patterns, with the greatest activity falling in three of those six intervals.5Icarus. Martian dust storm distribution and annual cycle from Mars daily global map observations The seasonality is driven by the planet’s orbital geometry. Mars has a more elliptical orbit than Earth, so it receives significantly more solar energy during southern summer, which heats the surface and atmosphere unevenly and creates conditions ripe for dust lifting.
Topography also matters. The Hellas Basin, the deepest impact basin on Mars, acts as a natural engine for storm generation. Winds flowing down its steep slopes accelerate, and the temperature contrasts between the basin floor and the surrounding highlands create strong local circulations that kick up dust. Simulations show that surface wind stresses associated with the basin’s sloping terrain, along with thermal tides and traveling weather waves, are the primary triggers for the large storms that occasionally grow into global events.6Journal of Geophysical Research: Planets. Simulation of spontaneous and variable global dust storms with the GFDL Mars GCM
Dust Devils
Alongside the large-scale storms, Mars is dotted with thousands of dust devils on any given sunny afternoon. These spinning columns of air form when the surface heats up under direct sunlight, creating a thin layer of warm air that rises rapidly and begins to rotate. The horizontal temperature differences near the ground supply the initial spin, which then gets tilted into the vertical by convective updrafts.7Journal of Geophysical Research: Planets. Numerical simulation of Martian dust devils
Martian dust devils can be enormous compared to their Earth counterparts. Some have been photographed towering several kilometers high and stretching hundreds of meters across. They are far more than a visual spectacle: dust devils collectively lift roughly half as much material into the atmosphere each year as all regional and local dust storms combined.8Journal of Geophysical Research: Planets. The distribution of dust devil activity on Mars That makes them a major contributor to the persistent background haze that gives the Martian sky its butterscotch color even when no large storm is active. Rovers have directly witnessed dust devils passing nearby, and some have even benefited from them: gusts from a passing vortex occasionally sweep accumulated dust off solar panels, temporarily restoring lost power.
Cyclonic Vortices Near the Poles
Mars also has cyclonic storm systems that bear a passing resemblance to terrestrial low-pressure weather systems. These are most commonly spotted near the edge of the north polar cap during northern spring and summer, when strong temperature contrasts between the cold ice cap and the warming lower latitudes drive spiraling wind patterns. Orbital cameras have captured arc-shaped and spiral cloud features traced by dust and water-ice clouds circling these low-pressure centers.9Journal of Geophysical Research: Planets. Martian Atmospheric Disturbances From Orbital Images and Surface Pressure at Jezero Crater, Mars, During Martian Year 36
One cyclone in particular has been returning to the same general location for decades. Observed repeatedly between 1995 and 2018 at roughly 60°N latitude, it reappears each Mars year during northern summer. In some years it produces a dramatic double-cyclone structure, with a companion vortex forming alongside the primary one. In other years it shows an annular cloud ring with a large water-ice cloud streaming off to the east.10Journal of Geophysical Research: Planets. A Seasonally Recurrent Annular Cyclone in Mars Northern Latitudes and Observations of a Companion Vortex These cyclonic systems can create measurable surface pressure oscillations detectable by instruments like those on NASA’s Perseverance rover at Jezero Crater, hundreds of kilometers away from the storms themselves.11Journal of Geophysical Research: Planets. Martian Atmospheric Disturbances From Orbital Images and Surface Pressure at Jezero Crater, Mars, During Martian Year 36
Carbon Dioxide Snowstorms
Perhaps the most alien type of Martian storm is the COâ‚‚ snowstorm. During polar winter, temperatures drop low enough for carbon dioxide, the main component of Mars’s atmosphere, to freeze directly out of the air. This process builds the seasonal polar ice caps that grow and shrink each year. But it does not happen only at ground level. High-altitude COâ‚‚ ice clouds form at altitudes up to about 40 kilometers, and under the right conditions, ice particles fall from these clouds as genuine snowfall. Simulations indicate that roughly half of the seasonal polar ice cap is built by COâ‚‚ snow falling from clouds, with the other half forming by direct condensation of gas onto the cold surface.12Geophysical Research Letters. Carbon dioxide ice clouds, snowfalls, and baroclinic waves in the northern winter polar atmosphere of Mars
These snowfalls are not random. They are closely linked to traveling planetary waves, large-scale atmospheric disturbances that create alternating warm and cold phases as they circle the planet. COâ‚‚ clouds and snow tend to form during the cold phases. Depending on longitude, snow particles that form at heights up to about 20 kilometers can reach the surface, while in other regions the lower atmosphere is warm enough to sublimate the falling snow before it lands. The topography beneath the clouds also shapes the snow pattern: mountain features can generate diffuse clouds with snow tails extending many kilometers downwind, sometimes reaching all the way to the ground.13Journal of Geophysical Research: Planets. Carbon dioxide snow storms during the polar night on Mars
Water-Ice Clouds and Nighttime Convection
Mars also has water-ice clouds, though they are much thinner and more tenuous than Earth’s. A belt of water-ice clouds forms regularly around the equator during northern spring and summer, and patchy clouds appear at high latitudes. What is less intuitive is that some of these clouds generate convective activity at night. Radio occultation measurements detected layers of neutral stability in the atmosphere at high northern latitudes during early Martian summer, a signature of convective mixing at a time of day when such mixing normally does not occur. These nocturnal mixed layers were found at altitudes starting about 3 kilometers above the surface, at the same height as the nighttime cloud layer detected by the Phoenix lander’s lidar instrument. Their depth ranged from less than 1 kilometer to more than 5 kilometers.14Icarus. Nighttime convection in water-ice clouds at high northern latitudes on Mars
The mechanism is essentially the same as what drives thunderstorm anvils on Earth, but in miniature and without the liquid water. As ice crystals form and release latent heat, they destabilize the surrounding air, triggering convective overturning within the cloud layer. The result is localized “storms” of falling ice particles, a far cry from an Earth rainstorm but a genuine form of precipitation on a world where liquid water cannot exist on the surface.
Orographic Weather Over Giant Volcanoes
Mars’s extreme topography creates weather phenomena that have no real parallel on Earth. The Tharsis volcanoes, including Olympus Mons and the three Tharsis Montes, are so massive that they force the atmosphere into dramatic patterns. Arsia Mons, the southernmost of the Tharsis Montes, produces an extremely elongated cloud that stretches hundreds of kilometers downwind during certain seasons. Mesoscale modeling reveals that a downslope windstorm on the volcano’s western flank triggers a hydraulic-jump-like feature: air that has accelerated downhill suddenly decelerates and is forced sharply upward. This updraft propagates high into the atmosphere, causing temperature drops of up to 30 K at altitudes of 40 to 50 kilometers and generating the visible cloud plume.15Journal of Geophysical Research: Planets. An Extremely Elongated Cloud Over Arsia Mons Volcano on Mars: 2. Mesoscale Modeling
These volcanic cloud features recur year after year at the same season and local time, making them among the most predictable weather events on the planet. They offer a useful natural laboratory for testing atmospheric models because their timing and structure are so consistent.
Electrical Activity in Dust Storms
One long-standing question is whether Martian dust storms produce lightning. On Earth, volcanic eruptions and sandstorms can generate electrical discharges through triboelectric charging, where colliding particles transfer charge to each other. The same physics applies to Martian dust. Laboratory experiments using simulated Martian soil in low-pressure carbon dioxide atmospheres have demonstrated that grains become charged through collisions, and when wind separates large and small particles vertically, an electric field builds. Under certain conditions of pressure and wind speed, electrical discharges do occur.16New Journal of Physics. Experimental evidence for electrostatic discharging of dust near the surface of Mars
Theoretical work suggests that while Mars’s atmosphere generally does not meet the conditions for lightning as we know it on Earth, electrical discharge becomes possible under extremely dusty conditions when surface winds are strong enough to loft a very high mass of particles.17Journal of Geophysical Research: Space Physics. Electrostatic discharge in Martian dust storms No mission has yet unambiguously detected lightning on Mars, but the laboratory evidence makes it plausible during the most intense dust events. Future landers equipped with radio-frequency or optical sensors could settle the question.
How Storms Drive Water Loss From Mars
Storms do more than rearrange dust. They are actively helping Mars lose what remains of its water. When dust storms heat the middle atmosphere, water vapor that would normally stay trapped near the surface gets lofted to high altitudes where ultraviolet light breaks it apart into hydrogen and oxygen. The lightweight hydrogen then escapes to space. Measurements during a regional dust storm showed that a single such event can boost the rate of hydrogen escape by a factor of five to ten compared to calm conditions. Because regional storms occur in most Mars years, they may account for a large fraction of the planet’s total water loss over geological time.18Nature Astronomy. Martian water loss to space enhanced by regional dust storms
This finding has reshaped how scientists think about Mars’s climate history. Early Mars likely had rivers and possibly an ocean, but most of that water is now gone. The traditional picture assumed water escaped slowly and steadily. The storm-driven mechanism suggests the loss is episodic and bursty, concentrated in the storm seasons and amplified whenever a global dust event occurs. It means storms are not just weather: they are agents of long-term planetary change.
Wind Force on the Surface
A common misconception, fueled by the movie “The Martian,” is that Martian storms produce wind forces strong enough to knock over a spacecraft or hurl heavy objects. Wind speeds during major dust storms can reach well over 100 kilometers per hour, which sounds frightening. But because the atmosphere is so thin, the dynamic pressure exerted by that wind is a small fraction of what the same speed would produce on Earth. A 100 km/h Martian gust packs roughly the punch of a gentle breeze here. The low atmospheric density does, however, affect surface geology in interesting ways: it allows wind-sculpted ripple features on sand dunes to grow much taller than their Earth equivalents before aerodynamic forces at the crests limit further growth.19Journal of Geophysical Research: Planets. A Broad Continuum of Aeolian Impact Ripple Morphologies on Mars is Enabled by Low Wind Dynamic Pressures
The real hazard from storms is not wind force but dust. Fine particles coat solar panels, reducing power generation. They settle on optical instruments and thermal radiators. And for future human explorers, inhaling the dust would be a serious health concern, because Martian particles are fine enough, averaging around 3 micrometers in diameter, to penetrate deep into the lungs. The dust is also highly oxidative and chemically reactive, properties that could damage lung tissue and other biological systems on contact.20PubMed Central. Potential Health Impacts, Treatments, and Countermeasures of Martian Dust on Future Human Space Exploration
Forecasting Martian Weather
As Mars exploration matures, so does the need for weather prediction. Landing a spacecraft on Mars is already harrowing, and atmospheric dust loading directly affects the process. Modeling studies for the Mars 2020 mission (Perseverance) found that horizontal wind speeds above 10 to 15 kilometers altitude could vary by up to 30 meters per second depending on how much dust was assumed to be in the atmosphere.21Earth and Space Science. MARSWRF Prediction of Entry Descent Landing Profiles: Applications to Mars Exploration That kind of uncertainty matters when you are threading a spacecraft through a narrow entry corridor at thousands of kilometers per hour.
Current Mars weather models have made real progress. A recent study comparing observed dust storm tracks with predictions from a global circulation model found strong similarities in storm speed and direction, demonstrating that the models capture the broad patterns of where and how fast storms move.22Journal of Geophysical Research: Planets. Making Observed and Modeled Martian Dust Storm Trajectories Visible Using a New Automatic Tracking Algorithm But challenges remain. Imperfections in the assumed dust distribution can cause large forecast errors when the dust field is evolving rapidly, which is exactly when accurate forecasts matter most.23Quarterly Journal of the Royal Meteorological Society. Assessing atmospheric predictability on Mars using numerical weather prediction and data assimilation Predicting whether a given regional storm will die out or escalate to global scales remains beyond current capability. For a crewed mission, that uncertainty would be more than academic: it would determine whether astronauts have enough solar power to operate for months at a stretch, and whether it is safe to attempt an ascent from the surface.
Dust Hazards for Future Human Missions
Engineers designing habitats and spacesuits for eventual crewed missions treat Martian dust as one of the top environmental threats. The particles are electrostatic and tend to cling to surfaces, making them difficult to brush off. They are irregularly shaped but with rounded edges, and their small size, typically 2 to 8 micrometers during dust storms, means standard filtration has to work harder than it would for coarser material.24PubMed Central. Potential Health Impacts, Treatments, and Countermeasures of Martian Dust on Future Human Space Exploration The chemical reactivity of the dust, largely due to perchlorates and iron oxides on the particle surfaces, adds a toxicological dimension that lunar dust, itself a known irritant, does not share to the same degree.
Airlock designs, suit-cleaning protocols, and air-handling systems for Mars habitats all have to account for the reality that storms will periodically deposit fresh layers of this material on every exposed surface. A global dust storm lasting several months could reduce solar power generation to a fraction of normal, forcing reliance on nuclear power or very large battery reserves. The lesson from Opportunity’s loss in 2018 is clear: any solar-dependent system on Mars needs a plan for surviving extended darkness.