Forcing the router to pause until current user is loaded

I'm using Ember Simple auth, and I'm using an initializer to set the current authenticated user as a property on my session:

Session.reopen({
  setCurrentUser: function() {
    var id = this.get("user_id");
    var self = this;

    if (!Ember.isEmpty(id)) {
      return container.lookup("store:main").find("user", id).then(function(user) {
        self.set("currentUser", user);
      });
    }
  }.observes("user_id")
});

Is it possible to force the router to wait until currentUser has been set before ending the initial app transition? I want certain components to be able to access session.currentUser as soon as the app boots up.