Thanks for your question.
I'm terribly sorry to hear about what you're going through with your daughter, and it sounds like a very scary situation. She is obviously very angry about you and her father splitting up, and certainly needs some help in handling her emotions. Right now if you are afraid that she may harm you, herself, or anyone else, you may have to consider calling the police. Of course that would be the last resort, but in some cases it is the only way to ensure everyone's safety. Since she is under 18, with the police involvement it may also be possible to have her involuntarily committed to the hospital until she is considered to be stabilized.
Individual and/or Family Counselling would be the most logical step, especially considering how extreme her behavior is right now. There are also medications that she doesn't have to take permanently, but would help her to get her emotions more under control in the short term. If you are having troubling figuring out where to start, the easiest first step would be to set up an appointment with a psychiatrist so that she can have a proper evaluation done. That will help you get some appropriate recommendations, and figure out the best way to proceed from that point. Your doctor should also be aware of the best local resources for these types of problems, so your discussion with them should prove to be helpful.
If your daughter has never otherwise been this way, she will eventually pull through it. This is obviously a time of crisis in her life, and she may feel betrayed or hurt by the people who have supported her the most. It's not uncommon for that to translate into some scary or reckless behavior, and the circumstances do make it difficult for you personally to get through to her. The hope is that getting her set up with some proper supplementary support will help her to resolve these issue, get back to trusting her parents, and being herself again.
I definitely wish the you the best with all of this. If there is anything else I can do to help please let me know.