Living on the Skye and knowing Wester Ross I'm not surprised that these accidents happen because I've seen similar happen right in front of me. Maybe you've been on the West Coast, maybe not, but the winds even when the storm doesn't have a name, can be very powerful. Just around our house it can be difficult at times not getting blown away; sheds go missing, roofs get ripped off and tiles go flying. Tipping over a van is not a problem in these instances. And in some places the roads are close to steep banks - so rolling down it is very possible.
In one incident on a road leading down to Broadford, a gust of wind took a panel van off the road in front of me and it rolled over down the bank, just like the motorhome mentioned in the article. The driver was OK fortunately. Even in my car it was a little hairy and surprisingly the Skye Bridge wasn't closed to high sided vehicles at that time.
On the A66 one winter an artic on the other side of the dual carrageway got hit by a gust of wind and just tipped over, just as we went past on the other side. Ok, it didn't roll but just shows the power of the wind. Again fortunately no one was over taking at the time.
Not wind related but coming down the hill towards Sconser a mini-van full of tourists hit a patch of ice and went off the road and rolled down the bank, finishing up on its side. By the time we got there the occupants were crawling out the door on the top side of the van.