The Martian atmosphere is about 1 percent as dense as on Earth, meaning it takes stronger winds in order to get objects airborne. Global dust storms are known and have been studied from Earth, but these large storms block out the sunlight which also powers them. As sunlight warms the ground, it also warms the air close to the surface. The warm air lower down and the cooler air higher become unstable, just like on Earth during thunderstorms. As the warm air rises it lifts dust up as well and creates everything from small localized dust devils to planet spanning storms. The larger storms typically only happen in the southern hemisphere of Mars, but can last months. As the dust blocks out sunlight, it in turn stops the air above the ground warming and therefore storms the pattern needed for storms to develop or continue. With the weather calm, it’s not long before the air close to the ground starts to warm again…
The dust storms on Mars can be damaging to equipment exposed to them and particularly cause problems for solar panels generating power. Although the atmosphere is thinner than on Earth, the Viking Landers measured wind speeds of up to 113 km/h (70 mp/h) during storms, and these winds can whip up sand and small rocks, damaging items, clogging machinery, etc. The small particles moved around by these storms are slightly electro static, and this causes them to cling to everything they make contact with and can also hamper clean up operations. Every year Mars has dust storms big enough to cover continents which can last for weeks at a time, and on average every few years has planet encircling dust storms which can be much more intense.
Dust Storms will begin as the only hazard with a lead in time - all others happen instantly at the time of generation. When created, the colony will be given between 4-24 hours of warning that the dust storm is approaching. Each hour before the dust storm hits the colony, there is a 3% chance for it to dissipate, in which case the storm diverts away or is no longer strong enough to cause damage.
If a dust storm does hit, then checks are made as normal for damage to the colony, but no other hazards can be generated during this time. The next hour, instead of checking for other hazards the dust storm has a 60% of happening again (and thus, a 40% chance of disappearing and no longer being active.) If the dust storm hits again for a second hour, it should have a newly generated intensity. This process will continue for as many hours are required before the storm disappears on its own, and only then can other hazards begin to be generated again.
The Dust Storm hazard inflicts 25 points of damage each time it damages an ownership/sponsorship card. Please be aware that due to unpredictable nature of dust storms, they can cause damage to the colony hour after hour until they dissipate. While each instance of damage is lower than other hazards, the cumulative damage can cause them to be one of the most destructive events on Mars.