Yes, howl is a Scrabble word!
...and is worth 10 points in Scrabble, and 10 points in Words with Friends
howl
Verb
1. Emit long loud cries
2. Cry loudly, as of animals
3. Make a loud noise, as of wind, water, or vehicles
4. Laugh unrestrainedly and heartily
Noun
1. A long loud emotional utterance
2. The long plaintive cry of a hound or a wolf
3. A loud sustained noise resembling the cry of a hound
What Scrabble words can I make with the letters in howl?
3 Letter Words
2 Letter Words