Rime is one of the cooler weather phenomena we see during the winter months. It’s not that uncommon, but there are only a couple of cases per year of something as extreme as this photo, which was taken by the Mount Washington weather observers Tuesday morning.
I know, I know. It looks like it’s Photoshopped, but I promise it’s not. That is the actual summit sign. The observers said they scraped off the front of the sign, and then the sun melted away any remaining ice. The harsh lighting and deep blue sky lend to its otherworldly aesthetic.
— Scotty Strachan (@scottysci) January 31, 2017
Hard rime ice forms when it’s foggy and temperatures are well below freezing. Water droplets adhere to a surface (like this sign) and freeze instantly. The temperature of the objects that the frost is forming on needs to be well below freezing, too.
At 6,288 feet, the “fog” was actually clouds. The ice grows “into” the wind, and in this case, the wind was blowing from left to right. The wind blows the tiny water droplets onto the surface and the natural ice sculpture grows.
That must be a pretty sturdy summit sign.