Dust storms are Metrological events. Dust storms happen when wind kicks up loose surface dust into the air, and in some cases, send dust particles flying in all directions.
Sol 6 / Sol 18[]
The Ares III dust storm was an extremely unlikely weather event that was completely unexpected. No dust storm on Mars has ever been recorded as being more powerful. During the sand storm, the Meteorological tracking stations at Ares III recorded up to 8,600 Newtons of force, more than any Martian sandstorm ever. For reference, the MAV con only handle 7500 Newtons of force. The image above shows evacuation footage form Mark Watney's suit-cam during the evacuation, seconds before his signal cut out.
The Book Storm[]
In the book, whilst Mark is driving to the Ares IV MAV in his Rover another dust storm occurs. It's not particularly strong but as it's effecting the atmosphere and visibility, less sunlight is reaching Mark's solar panels. If he kept on driving into the storm he would have ran out of energy and his life support would shut off effectively killing him but with no way for NASA to contact him and warn him of the upcoming danger the world could only wait and hope Watney realised what was happening before it was too late.
Thankfully, Mark did realise the slight diminish in energy and linked it to a possible dust storm. He assume the storm had take on a spherical/circular shape and drove around it as best he could, managing to get out on the other side unscathed.