Planets Watching Mars' Amazing Global Dust Storms: Photos Mars has a dynamic atmosphere that often erupts with dust storms that engulf the entire planet; understanding storm patterns will be critical to safeguard Mars missions in the future.

Regional dust storms on Mars may not be so random after all. NASA has uncovered a pattern of three types of storms that occur "with similar timing" in different Martian years, based on observations of Mars since 1997. You can see more details here. Understanding how these storms arise will be crucial to protecting spacecraft -- and humans! -- on the surface of Mars in the coming years. Here are some pictures of dust storms on Mars from the 1970s to the present day.

Before Mariner 9 surveyed a global map of the Martian surface starting in 1971, what we knew about Mars came from a few flybys in the 1960s and 1970s. All of these spacecraft coincidentally missed some of the most interesting features on the planet, such as the gigantic chasm known as Valles Marineris, and the crust-bending volcanoes like Olympus Mons, which exceeds Mount Everest's peak height. But when Mariner 9 arrived at the planet, there wasn't much of a view -- there was instead a huge dust storm, so fierce that it hid most of the mountains from view. This is an image of Olympus Mons just barely poking through the top of the storm. Scientists weren't even sure what they were looking at until the massive clouds subsided. Image: In this 1971 picture from Mariner 9, the top of Olympus Mons (the tallest mountain on Mars) pokes out from a global dust storm. Credit: NASA/JPL

When a huge storm erupted on Mars in 2001, scientists were very excited because they had both the Mars Global Surveyor at Mars, and the Hubble Space Telescope in Earth orbit. Both of these observatories gave a close-up view of what was happening on the Martian surface day by day, allowing planetary scientists to learn more about the planet's dust behavior in then-unprecedented detail. "What we have learned is that this is not a single, continuing storm, but rather a planet-wide series of events that were triggered in and around the Hellas Basin," said Mike Malin of Malin Space Science Systems, Inc., San Diego, lead investigator on the camera, in a 2001 press release. "What began as a local event stimulated separate storms many thousands of kilometers away. We saw the effects propagate very rapidly across the equator — something quite unheard of in previous experience — and move with the southern hemisphere jet stream to the east." Image: These two Hubble Space Telescope images show Mars before a huge dust storm struck the planet in 2001, and during (at right). Credit: NASA, James Bell (Cornell Univ.), Michael Wolff (Space Science Inst.), and The Hubble Heritage Team (STScI/AURA)

In 2012, Curiosity had just been on the surface a few weeks when NASA began seeing a dust storm arising on the Red Planet. By mid-November, both Curiosity and Opportunity saw a slight darkening in the sky because of the dust. It gave an early opportunity for scientists to look at the air pressure and temperature using Curiosity's Rover Environmental Monitoring Station (REMS). "One thing we want to learn is why do some Martian dust storms get to this size and stop growing, while others this size keep growing and go global," said Rich Zurek, chief Mars scientist at NASA's Jet Propulsion Laboratory, in a 2012 statement. Opportunity's operations would have been more affected than Curiosity since Opportunity relies on solar power, scientists said at the time. But the storm dissipated fairly quickly, allowing normal operations to continue -- at least this time. Image: This image of a regional dust storm in 2012 took place while the Opportunity and Curiosity rovers (marked on the map) were working on the surface. The image was taken by the Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/MSSS

With rovers on the surface, NASA has a vested interest in watching dust storms to make sure it can take measures to protect Opportunity and Curiosity (if necessary). This includes looking at the pattern of past dust storms to see what happened at that time. Luckily, the Mars Reconnaissance Orbiter can provide close-up views of local skirmishes, such as this 2007 dust cloud spotted here near Utopia Planitia (in the northern atmosphere). This photo was re-released in 2012 when scientists were preparing for the Mars Curiosity mission, which landed Aug. 6. Part of their job was to watch the planet for "similar small storms that could either drift over the landing site or stir up dust that moves as haze over the site," NASA wrote at the time. The particular dust storm shown here only lasted about 24 hours, but some Martian dust storms last weeks or months. Image: This is a 2007 image of a dust storm taken by the Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/MSSS