Category: "Ice Science"

The Growing Icicle's Hollow Tip

January 17th, 2020
If you inspect the tip of a growing icicle, you might be surprised to find it hollow. Skeptical? Well, if you think the conditions suitable for icicles outside, put a toothpick in your pocket and go outside. Then when you see a likely candidate, poke… more »

Martini Hoar (raise a tiny glass?)

October 19th, 2019
The hoar-frost crystal shoots up like a thin, solid straw, then suddenly opens up into a cup-like shape. I have seen it often enough to give it a name: "martini hoar". The cup can be weirdly segmented and polyhedral, but it nevertheless widens suddenly.… more »

Puddle gets its grooves (upon freezing), part I

February 16th, 2019
These grooves appear on the surface of frozen puddles. [image:111] Most grooves are straight lines, and most of these also appear to have relatively symmetric sides, such as those marked #s 1, 2, & 4 in the above image. But some, such as #3, have… more »

Grain boundaries between crystals in big ice

November 6th, 2017
Most snow crystals are single crystals. Being single is an outcome of their growth process and small size. On the other hand, most larger ice formations are not single crystals. These latter types are called "polycrystals". A polycrystal usually appears… more »

How clouds form snow

January 14th, 2017
To understand snow formation, one must know a little about clouds.  Q: What is in a cloud? A: Air, dust, vapor, droplets, and often, ice.  Q: How much air? How much liquid water? How much ice? A: The answers will probably surprise you. See my short… more »

Lots of Hair Ice

December 19th, 2014
My older sister sent me this photo on a recent morning. This is hair ice growing from an alder tree. All of it grew overnight, formed when liquid water near the outer trunk surface (beneath the bark) froze. This creates an ice front in each pore-like… more »

Glaze-rime Ice Buildup Facing Creek

November 23rd, 2014
Here's a reed of some sort, with a glaze of clear rime on the side facing a creek. How did the clear ice get there, and what is the white ice on top of it? The fact that the clear ice is just on the side facing the creek indicates that the ice came from… more »

Smaller Hoar Growing on Larger Hoar

November 22nd, 2014
Cold air came down the interior, spilling through gaps in the Cascades, cooling the western side. In the Seattle area, we got our first frost on Nov. 11, but the days stayed cold. Areas in the shade never lost their hoar, so the hoar frost kept growing.… more »

It’s not a rainbow (it’s better)

August 12th, 2014
In summer, the sun reaches higher elevations, bringing the possibility of new atmospheric displays. I saw this one in mid-June. The top, upward arc is the more familiar and common 22-degree halo. But pay attention to the one on the bottom. Its colors… more »

Halo in the sky? Uh, I don't see no halo...

April 20th, 2014
After a few days of fine bright spring weather, the barometer falls and a south wind begins to blow. High clouds, fragile and feathery, rise out of the west, the sky gradually becomes milky white, made opalescent by veils of cirro-stratus. The sun seems… more »