The first point could be that the description of the growling dog gives an effect of being surrounded by danger, especially with the repetition of the growling coming from everywhere. It give a feeling of being trapped and Stephen king uses this to create tension.
The second point could refer to the woman and her strange actions because she is frightened of the unknown, and often being in the outside exposes you to things you can’t always escape from. King uses this to convey a fearful setting that a reader can relate to.
