A dust storm was probably brewing.
This isn't the first dust storm you've been through, is it?
The dust storm might work in their favor, but it would only increase their discomfort.
He watched explosions wrack his planet until they rose high enough that the toxic dust storm he'd started marred the surface of the planet from view.
When overtaken by a dust-storm it falls on its knees, and stretching its neck along the sand, closes its nostrils and remains thus motionless till the atmosphere clears; and in this position it affords some shelter to its driver, who, wrapping his face in his mantle, crouches behind his beast.