It never rains but it pours

Trying to get ready to visit family in Devon . Alert from the Bee inspector warning about high levels of varroa mite infestations with advice to treat asap. We put some formic acid treatment into each hive as this is considered safe while the honey flow is on. I checked later and to my horror found a lot of dead bees at the entrances to all the hives. Out came the formic acid treatment and it was dumped into the bin. Meanwhile I noticed a swarm on the apple tree which Brendan collected as it started to pour with rain. I had to shelter in the garage to get a hive cleaned out and new brood frames fitted in readiness.
This is a quick snap of the swarm just as the rain started and is a rather blurry. Note how all the wings act a bit like a thatch to keep the bees dry.