Video of growing ice spike

March 6th, 2014
Take about a cup of water, place in a glass flask, then plunge in liquid nitrogen. Watch. What happens in that video is that the water starts to freeze from the bottom and sides of the flask, and the ice also spreads across the top surface. When the… more »

The end of snow

March 1st, 2014
This recent front-page article caught my eye: The writer is an avid skier-snowboarder, and thus concerned about the future of his sport. The facts he relates paints a grim picture: - In the past 47 years, a million square miles of spring snowcover has… more »

The cup and the butterfly

February 25th, 2014
In early January, while visiting a cold, dry region, I saw this frost on a wooden fencepost. The pattern resembled a cluster of butterflies. In the shade, these "butterflies" were blue, reflecting the blue sky. In the sun, they were bright white: These… more »

Raindrops on ice

February 23rd, 2014
When water droplets land on ice, what happens? If the ice is at least several degrees below zero (celcius), the drops freeze quickly, and build up a whitish, bumpy surface. When the ice surface is heated to melting, the droplets vanish into the melt.… more »

Bending of branch and pond

February 11th, 2014
Bending bending bending                 The fir branches are bending                 They are waiting for more snow The famous Japanese poet Basho wrote a poem like the above, except it was about bamboo bending under the snow load. I was… more »

Hoar that grows down and out

February 9th, 2014
It had been a continued spell of cold days and nights, the ground snow-free, the air clear and dry. No film-frost on the cars in the morning, and no spikes of hoar frost sticking up on grass or post. The only signs of ice had been the frozen pond and… more »

One hundred twenty one forms of falling ice: the new snow classification system

January 22nd, 2014
When I last wrote about the classification of falling snow and ice (02/14/2010), I discussed the 1966 Magono-Lee system. At the time, this system was the most recent one, and as such, the one generally used in meteorology. And to those who wondered how… more »

What makes the thick curvy lines in frozen puddles?

January 27th, 2013
My sister recently sent this photo of a frozen puddle, a little over a foot across. Something broke out a piece of ice in the upper right, but it’s mainly a complete glaze over the top. (The white dots are rimed snow crystals. Click to zoom in and see.)… more »

Rime falling from branches

January 24th, 2013
While riding my bike home the other day, I saw what appeared to be a patch of light snow. It was the only such patch around. Looking closer, I could see that it consisted not of snow, but of chunks of partly melted rime deposits. (Note how the pieces… more »

Rime, freezing fog, and crystalline spider webs

January 22nd, 2013
The Pacific Northwest has been foggy a lot lately, but the fog droplets have been subzero, or supercooled. When such fog droplets hit an object, they almost always freeze. The resulting frozen aggregate is called rime. Freezing fogs make rime. The… more »