How do I deal with this behaviour?

It is no good talking to her when she is in the grip of the tantrum but you need to sit her down later and ask her what is really the matter to make her so uptight and angry. I assume that is calmed down and they had the friends over on Boxung Day. Have you discussed it with SIL?

Boxing not Boxung!

I think that you did the right thing getting away. If you can't discuss it with her then you need to distance yourself, and not engage, once she starts.

I agree with Blencathra. This isn't about you (said kindly) and none of it is your fault. You sound helpful and reasonable but if your daughter can't see that through her tantrums I think the best thing for you to do is what you did: walk away and leave her to calm down in her own time. It might be best not to bring up what happened at all. Least said, soonest mended.

So, in answer to your title asking how to deal with it: do nothing except keep out of her way for a time. Good luck.

PS I turn my phone to "Do not disturb" mode at night. Your daughter could have knocked on your bedroom door to tell you about the dog.

PPS Does she dislike the dog?

It does seem to be a bit of a mystery as to what exactly was your fault. The fact she had a disturbed night's sleep? She has children. Does she never have to get up for them? A broken night's sleep is nothing for a mum. I don't see how this could affect the visitors coming on Boxing Day. What could she have said to them? "oh, I have to cancel the day as I had to get up to mum's dog once in the night"?

There's another reason at the bottom of this and I doubt it's you.

Quite strange behaviour really - you enjoyed Christmas day but did your daughter or was she very stressed with it all. Young children, a dog in the house, visitors staying and visitors expected Boxing Day with all the preparation that entails could have been a huge pressure (speaking from a personal point as it was the same here without the dog thrown in but my cats running scared all the time of my grandchildren). She may have just been tipped over the edge. You did the right thing to leave but this in itself may have made her feel guilty and not able to cope. Have you spoken to your SIL to ask how often she boils over like this. Could it be PMT? I hope you have been able to talk to her since the outburst and been able to clear the air - the longer its left to fester the harder it will be.

Only you know if this is normal behaviour for your daughter. If she’s always had a short fuse and can’t deal with stress well, then this will be nothing new. If this is out of character then I agree a quiet word with SiL might help.

Perhaps the daughter has PMT, or is menopausal.

Thank you everyone for your responses. In response to them. Yes she likes the dog, she too has a dog. SIL did all shopping for and cooked the Christmas Dinner, which he enjoys. My daughter happily played with the children and enjoyed Christmas Day. My SIL is upset by this behaviour, but says he keeps his head down and let’s things pass. He can’t understand why these outbursts happen. In the past there have been other incidents and after they have calmed I tried to talk to her which made matters worse. Even if I’m not actually there they problem is frequently placed at my door. I think it may be PMT, but even that suggestion when made was the trigger for further anger.
Normally she is kind , caring and very popular. (Although I have to say not always to me? She has a wonderful,supportive husband. Two lovely children. She doesn’t have the pressure of working and running a Home. Everything is very positive for her. These periods of anger are distressing for everyone.
Thank you again for your responses, sharing here has helped.

What kind of relationship have you had with your daughter as she grew up? Do you think she has some unresolved issues that she has surpressed? These may not even be things you did wrong but stuff like sibling preferences (perceived) or jealousies about other stuff: unfortunately these things can seep into adult life and although your daughter clearly loves you she seems to struggle with repressed anger that comes out in sudden out bursts?

I think it was above and beyond the call of duty for her to allow the dog to stay.

Maybe your daughter is like this because everyone tiptoes around her?

I don’t know how old your daughter is, but as someone has already said, is there any possibility that she could be menopausal? I had always had a bad temper, but my mid forties, I had similar problems; mercurial temperament, dreadful outbursts - poor DH at his wits end. Just a thought.

It sounds to me, too, like a hormonal thing, but someone could perhaps point her to some form of therapy or a neurological checkup.

You say she doesn't go out to work - is she perhaps a little frustrated with herself, despite doing a good job running a home, family and pets? Your SiL shouldn't stick his head in the sand, either - this could be important, and it could get worse.

It's certainly nothing to do with you or the dog whining in the night. Throwing the present back at her husband is irrational behaviour and she may do this at any time and harm her kids or her pets.

Sorry to sound so negative. It's just that it would be sad to see a family who is obviously otherwise so normal and peaceful go to pieces because of something that could be rectified.

Also, following on from Greyduster's comments - can you, as her mother, perhaps relate to this behaviour? I know that I can totally sympathise with my DS2's apparent idiosyncrasies, and I am learning about myself in the process!

Please try and find a way of helping her, for your own peace of mind. I hope I haven't worried you - these are just my thoughts, without knowing the whole story, of course, as are the previous posts the thoughts of all who have read your story.

Thank you to everyone. You have given me a lot to consider. Hope fully I can find the way to be supportive and help.

It might be because she doesn't go out to work. Just being an at home Mum can be very frustrating -even more so today when on a whole street you won't find any non working Mums.
Paticularly as her mother you can't praise her situation when she is obviously unhappy with her life and it overcomes her every now and again.

DD2 started work after 6 years at home and I was surprised at the woman who emerged. She even walked differently and she definitely talked differently. Perhapy your daughter needs to make some plans for looking for a job later on.

To be quite honest I woud be quite annoyed is someones dog was keeping me awake.Added to that I find christmas quite stressful without pets keeping me awake, but she does seem to have gone OTT about it.