Pogonip

The past week we’ve been waking to this……. 

Trees and grass ‘painted’ as if by Jack Frost himself.  It burns-off during the daylight hours and almost magically reappears from the overnight fogs. This winter meteorological event is a consequence of freezing fog.  Sometimes called radiation fog, valley fog or freezing fog it is also called pogonip – a Shoshone word for cloud. 

Fog materializes when there is cooler air coming in contact-with a warmer body of water or moist surface like a swamp or wetland. 

Freezing fog materializes when the air temperature is below freezing and the water droplets in the fog become super-cooled. These super-cooled water droplets stay in liquid state until they drift into contact with a surface they can freeze-to. Grass, twigs, trees, leaves and so-forth. 

It’s really a rather striking effect and pleasing to the eye. It is also something to be reckoned-with as it can result in ice build-up on roads – especially bridges – which have no ground insulation. It can also build-up on power lines with the result pf power outages. 

Drive carefully on mornings like this.

Or just stay-in and drink coffee.