Sorry Markus, between which two?
There is an easy way to check for any changes related to dust storms - comparing before and after images of Mars. Not now because of the current storm happening, but between previous dust storm events.
However, regarding changes due to shifting dust features, these would be dimensionally insignificant to what we can resolve from here on Earth. Multiple dust events would need to occur before we are able to notice changes.
Hmmm, maybe this is what happened to all the Martian canals...
