What is this?....They are masses of insects of some kind
No interactions present.
You have a better chance of another opinion if you post it in Invertebrates (you can edit the group in the original observation - you need not post again).
recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.
I have seen a similar 'swarm' of collemola, but with fewer individuals on beech leaf litter (some years ago).
Lat/Lng: 47.4431, -121.9769