Welcome to FMCA.
There are no real set rules. The main item is knowing your coach and how it handles is different conditions.
Basically, every coach will handle differently depending on how one loads them, the condition and type of tires and wind direction. Cross winds are the pits, while wind coming head on kills MPG, but are drivable. Wind from behind adds to MPG.
When the red flags are out, just stay put. I have been to close to a wall cloud once or twice and found cover. Also been inside the coach when it listed a little more them we would like.
Always parked the the awning side down wind. Strong winds can and will peel then off the coach under the right conditions.
In over 175,000 miles it has only happen 3 or 4 time where we felt, what I would call very nerves conditions.
You need to adjust your speed in most cases, when it comes to snow, sleet and ice; one needs to get off the road !!!!
The surface area of the coach, the total lack of traction and very little wind can push the coach off the road !!!!! So just find a place to pull off, keep the slides in and weather out the storm.
In some cases you maybe the only coffee shop and canteen for miles. One can see the best and the worst in people.
Just go with the flow and enjoy the fact that you have a house on wheels.