Alex, just sent you an email but I would bet these are the famous NNE black flies. Much smaller than house flies, really look like gnats. Swarm to the point you can't go outside. In your eyes, up your nose, swallowing them. I always heard Mother's Day to Father's Day is blackfly season in NH. The black fly season is over in S NH and is now ending in my area of Central NH but your cold spot is even further behind. Wear the screen headgear or shirts, we have to for a week or so until they pass. There awful things and bite like crazy