Hi New Here, and

On one hand, I’m grateful that the accusation is so clearly outside of my control. I don’t control the weather or air travel.I don’t love my dog too much. It’s easy to see that this was generated on her end. On the other hand, terrifying to see that I actually have no control in preventing these outbursts.
I think it's helpful to keep in mind, that just about all your uBPD mother's emotional episodes are "outside of [your] control." And for that reason, you should not try to "prevent these outbursts." Just manage your exposure to unreasonable behavior -- you were not raised to be her punching bag. Then again, if your family dynamic is similar to mine, just about all my other family members were conditioned to be attentive to my uBPD mother's emotional distress.
I found that what worked for me best was by maintaining as formal and distant a relationship as possible. Play the role of adult child (within reason) but I stopped volunteering (emotional) vulnerability.
And - for the first time the outburst was rage directed at me (not at something I’ve done.) she doesn’t remember what she said but I do.
The tree remembers, the axe forgets.
I’m a bit freaked out to see that I’ve become a preferred target for her rage. I’ve become responsible for weather, my siblings, and for the reality that we are all growing up.
When you are receiving her anger, acknowledge the anger and then remove yourself from the scene. Chances are what she is actually upset about has nothing to do with your specific circumstance -- it has more to do with her internal disarray. It's just that when someone with BPD has an overwhelming affect, it is easier for them to blame their emotions on those closest to them who are willing recipients of their ire.
Unlike a tree, you can uproot and walk away.
I love my family so much.
And for this reason, I can understand why you'd be willing to tolerate a lot to stay in the orbit of your family. Just try to find a way to protect yourself -- distance and formality.
Best wishes,
Schwing