Try to spread out like this during plumes
(if you ain't too sure when plumes are, keep this formation too and dodge stuff that's currently happening accordingly)
Plumes do never happen at the same time as anything else but always shortly after 2 nasty things.
Plumes always happen after the Stomps.
Plumes always happen after Bombs (he does a landslide during bombs --> mountain buster before plumes, but the time between bombs and plumes is short)

So be ready to dodge plumes after stomps
And be ready to dodge plumes after bombs

Now for the plume dodge formation make sure to spread out like this even if there is no melee dps.
If there are randoms stacking on top of each other or whatever, let em do it, just pick a spot further away from them.

Best thing to remember is that a plume hits every 20 seconds. So someone on raid could call out scatter or something.

Yup yup what lance said. If someone who knows the patterns by heart can call for people to scatter before it happens the group usually does pretty well.

Even when peeps call out this spread is the way to go as it gives you enough space to dodge and you are certain not to lock someone inbetween a bunch of plumes