Vloggage - The Raining Trees of Hazlemere

I observed a very strange effect today. It wasn't raining at all ... unless you stood under a tree. 

Of course, what was actually happening was that the fog/mist was condensing on the tree branches and twigs and then forming droplets that fell once they got heavy enough. 

 It was rather odd though - like the rules of Nature had been reversed.

   

Oh, and as I explain in the video, the difference between fog and mist is the density of water in the air. 

When you can see further than 1000m it's mist. If you can't it's fog.

Fog is formed when any cloud type makes contact with the ground. Clouds form when water droplets condense and merge, but fail to achieve a size large enough to precipitate as rain. Clouds will form or drift closer to the ground when humidity rises or changes abruptly, or when wind speeds drop or acutely change direction. 

Mist, meanwhile, is also formed by water droplets, but with less merging or coalescing. This means mist is less dense and quicker to dissipate when wind, temperature, or relative humidity changes. Mists can form due to abrupt temperature changes (such as when exhaling in cold air), high levels of humidity (in a sauna, for example), or from evaporation or condensation, such as when rain hits sun-warmed rocks and street surfaces or evening allows dew to form.

So now you know.