Black Files out in Milan NH

No trace of them earlier in the week but they were out in force today. I loaded up on deet but they definitely were hanging around.

Are they elevation dependent, or something ?
Gnats in Whitefield today and nothing (ever ?) in Bethlehem or Sugar Hill.

They definitely vary their initial onset around the regions by days or weeks. They do tend to be more annoying near stream and rivers but the spot I was at in Milan has no nearby open water. nearby. Thankfuly my house in Gorham is also not near open water and generally black fly season is short and usually not that bad. I and others have noted that as the season near the end that the back flies tend move up in elevation. On occasion the folks on the traditional Presi traverse weekend get nailed up on the summits.

They were out in Bartlett up to about 2500, then nothing. They weren't biting yet, thankfully, but still quite annoying. Seems like the precipice is before us.

There were good quantities of gnats and mosquitos in the Piper Trail parking lot Sunday (elevation 780' I believe). Not really swarming or biting yet but I'm sure that is imminent. Didn't notice much on the hike itself other than stray ones here and there and some of those large house fly type flies along the Sisters.