What does "the great calm has ceased, the quiet sands have run" mean. this is from poetry.

It is simply saying that all is now in chaos. I am assuming the part that is confusing is "the quiet sands have run." It could easily be alluding to the way that during a sandstorm, the calm sands of the surface are no longer there as the chaos of the storm casts them about.

I am not an expert at poetry, but I know a little. That means that the peacefulness of something, someplace, or someone has deflated. " The quiet sands have run means that, the calmness has had a uprising, and is no more calm, or calming. I hope I helped! :-)