Every child goes through times when they are angry. Anger is a natural part of life and children need to learn how to deal with it. By teaching your child how to deal with the changes in life and the anger they feel in a healthy way you'll set them up for a lifetime of happiness instead of bitterness.
Moving - Many people describe moving is a little bit like a death. Even if you don't think you will you lose your footing in the world. Your surroundings change, the people you depend on change, and everything is just completely different. The best thing that you can do is be understanding to a child who is angry about a move.
Moving is not the child's choice. They feel completely powerless about anything happening to them and need you to be sympathetic to their plight. Tell your child that they have a right to their feelings, and that they are normal. Then give them tools to deal with them such as letting them know they can come talk to you about anything.
Divorce - About half of all children will go through the experience of divorce. Divorce is yet another thing that makes children feel powerless. Children who feel powerless will likely act out in anger. The best thing that you can do when it comes to divorce is to keep a united front with your child's other parent.
Your divorce has nothing to do with how the parents feel about the children and it's important to voice that fact to the children so that they understand that both parents still love and support their children and that will never change. It's also important to keep the lines of communication open to allow your child to express his or her feelings as needed.
Major Life Changes - Anything in life that is a major change from moving up a year in school, to going through puberty can cause anger in a child. It all goes back to the feelings of powerlessness that the child is feeling. Showing your child by example how they are in charge of their actions can go a long way to helping children deal with all major life changes including loss.
Any type of change that is something a child has no control over can elicit feelings of anger. Teaching your child coping mechanisms such as deep breathing, taking a time out, and other methods that help them direct and control the feelings of anger will go a long way in helping a child avoid problems associated with anger such as lashing out and irrational behaviour.
The main point, we are trying to make, is that you need to be your child's safe place. They should be able to express their anger to you in healthy ways without judgment. You can be a sounding board for your child by asking the right questions, listening for the answer, and then guiding them toward rational solutions to dealing with whatever situations come up.