ESA's Schiaparelli entry, descent and landing module is due to land on Mars on October 19th.
Tweeted question: “There's a global dust storm forecast on Mars; Would such a storm compromise the safety of the lander?â€
Answer: Nah, bring it on! Or in their words
The lander has been designed to be able to cope with a global dust storm. In fact, a global dust storm would be amazing for the science package DREAMS, which for the first time will measure the electrification of the martian atmosphere due to dust grain friction.
Yet they wouldn't want loads of dust during the landing because there wouldn't be anything for the descent camera to photograph. Probably if a global dust storm appears, it will develop a few weeks after the landing.