Seems like it follows wet ot cold weather too doesn't it?
I've noticed it happens alot in cold weather, I haven't paid attention if it was wet.
I had two colic years ago within a week. The only thing the vet could figure was cold weather which results in cold water, and the horses won't drink it enough.
Rusty coliced in the summer tho...
Becky
Colic can follow weather where there isn't access to normal grazing... Bay colicked in our drought when the grass had all turned to dust.
This snow might be part of it too, sometimes they don't drink enough if water is freezing.... and hay can mold quickly if it's been damp.