Oh, yeah ... theater politics ... I hear you. There's more drama in drama than the audience ever suspects. Don't ask me how I know!
I agree with the posters who say to give a brief
explanation at the meeting. That is appropriate.
I urge you, though, to resist the temptation to think in terms of what would make Sue looking like the unreasonable one and you the reasonable one, or to pull rank (producer over director). That's sinking to her level and will just prolong the drama.
EllenS put it very well:
In your position, I would not go in with an overly-scripted response, because that sounds defensive. I understand theater politics, but in reality, this is not a "fight" between you and Sue, and I don't think you should in any way acknowledge or indicate that is even a possibility.
Just be very professional about it, as if this had been at your job, and make your explanation exactly the same as if Sue weren't even part of the story: you had to make the call, and, basing it on the forecast, the plowing, the parking, and the advice of professionals, you did your best. Don't
try to argue that it was the only
sensible call to make and anyone who did otherwise would have been wrong
-- there's no point: it's over. You don't have to win that argument.
I would also make sure to say that you regret that you had to do it (note: you're not saying that you did the wrong thing and wouldn't do it again, just that you're sorry you had to do it) and you know that everyone was disappointed; and so were you
. After all, it is important to acknowledge people's feelings, and I'm sure some of them were very, very disappointed -- they'd worked hard for a long time, and maybe that last performance was the one their family or a casting agent was coming to.
Then move on right away to asking whether everyone thinks that you all ought to establish some sort of protocol for the future so that everyone will be on the same page, which you probably should. Guidelines for cancellation due to weather? Communication system? (I urge you to use texting or phone trees for last minute stuff like this, not email. The stage manager for the show I am in now decided to use a Facebook group, so we all have to check it at least twice a day, and even that won't work if there's an emergency or last-minute message. Same for email, as you have learned. I wish she'd use text blasts or if that's a usage problem then a phone or text tree.) Rain dates? Venue change? Refunds? Parking alternatives?