I've found when confronted with irrational anger the best response is not to react. It's the other persons anger. They may want to put it on you, just side step it. As ACOA we are people pleasers and reactors. It's not easy to break that habit.
For example, when she called, you told her they would be back in 2 hours. When she came over anyway all full of rage asking why you are hiding the kids, just respond I'm not. They are playing with friends and will be back at xx o'clock. If you want to wait, come on inside, I'll put on a pot of coffee and make some room in the fridge/freezer for your stuff.
Just offer no resistance and maintain your composure.