nice pics - shows the weather and the ridges very well
If the weather was like that on the pictures, it would have been sufficient for VFR flying. Lots of airspace to fly around clouds and hills without the need to crash into something.
Well, we dont know how the weather was, but we can safely assume, that they had been on an IFR flight, otherwise it would not be necessary to request a clearance for lower altitude at first.
As we know, aircraft are equipped and crews should be trained and prepared to operate under IFR in all kind of WX conditions, only few situations like thundersstorms pose some danger enroute. Now the question, what had the weather to do with that accident?
Imho none at all.