Technical Terms For Ice

This question is really curiosity more than anything and with so many well read people on this forum I assume somebody would know. Is there a technical term for the "ice" that forms when snow continuously freezes and thaws, forming that cloudy gray ice that really is much softer and more grippable than true ice? I've read in various books about terms like verglas, hoarfrost, etc, etc and I'm wondering if there is such a technical term for this melted monorail ice/compacted snow. Seems misleading in trip reports to call this type of snow ice when it is much easier to travel on than ice that obviously formed from layers of freezing water, which is grayer and much harder.

When submitting trip reports on NETC it only distinguishes between blue, black and breakable crust and the frozen granular of monorail isn't truly the same thing either. Something I've pondered this year with all the ice and wide types of ice out there this year. I always post overly detailed trip reports and using the correct term to distinguish the types of ice is something I'd like to be able to do for the more advanced hikers out there (I'm sure the tennis shoe wearing explorers have no use for such a term).

Anyone who might be "in the know" on these terms or can point me in the direction of a website, maybe an ice climbing site? Appreciate the info if you have.

I believe that ski areas around here refer to it as 'packed powder'.

The ice buildup we are seeing this year is more accurately termed frozen slush. It's ice. It's hard. Mostly it's from all the rainfall we had and them the bitterly cold temps that immediately followed, before the runoff could get down the mountain. It may be white, but it's certainly not soft, unless it's melting.

Frozen water (ie liquid water that then froze) is often called "hard water ice" by ice climbers, particularly if temps are low and the ice becomes very hard. (For instance, water that dribbles down a rock face and then freezes would be water ice and hard water ice at low temps. A frozen puddle could also become hard water ice.) Frozen slush* might be called hard water ice if it is totally frozen (ie very cold). Warm, wet slush may simply be called soft slush, hard slush, or vertical slush (if vertical). Ice climbers may also simply describe ice as hard or soft. In the NE USA, essentially all ice is water ice, frozen slush, or ice crusts (water ice layer on top of snow from partially melted and then refrozen snow).
* Slush is, of course, snow that is saturated with water.

Neve is a stage between fresh snow and glacier ice (also called alpine ice). Glacier ice can be formed by pressure alone without melting and generally contains air bubbles. Over a period of years of pressure (and perhaps also warming and cooling) the crystals become coarser and more strongly cemented together until they become ice. Some of the air from the original snow will remain as air bubbles.

Snow itself is only pure ice at very low temps--as it gets warmer, it contains an increasing percentage of water. Snow can also soak up water flowing on/in it--temperate snow packs often have water flowing in them. Also snow crystals can change shape without ever melting--the water evaporates from the sharp-pointed crystal ends and deposits at non-pointed parts of the crystal. This is part of the settling process.

Snow and ice metamorphosis is a very complicated process...

Doug

Sublimation?

Neve.

Sublimation is when something changes from a solid to gas without going through water phase. Freezer burn is an example of this.

Chugach001 said:

Neve.

Sublimation is when something changes from a solid to gas without going through water phase. Freezer burn is an example of this.

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Isn't that a definition of sublimation from chemistry....is it the same process of "sublimation" when snow turns to ice on a glacier? I'm not saying your wrong I'm asking to know for own knowledge. I'm not too sure now that you raise it.

BISCUT said:

Isn't that a definition of sublimation from chemistry....is it the same process of "sublimation" when snow turns to ice on a glacier? I'm not saying your wrong I'm asking to know for own knowledge. I'm not too sure now that you raise it.

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Solid directly to gas is sublimation. It's the reason your ice cubes shrink over time in ice cube trays (and freezer burn as mentioned). The water is turning into a gas and condensing on the walls, etc. the freezer never rises above the melting point of water, so liquid water does not form in the process. Dry ice (solid carbon dioxide) is the most famous example...often seen as the thick, foggy, white gas used in concerts, magic shows, etc.

There is no separate word for gas back to solid. It is simply 'condensation' just like gas to liquid.

BISCUT said:

Isn't that a definition of sublimation from chemistry....is it the same process of "sublimation" when snow turns to ice on a glacier? I'm not saying your wrong I'm asking to know for own knowledge. I'm not too sure now that you raise it.

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Sublimation takes place on glaciers as part of ablation (overall loss of material). Ablation also takes place due to melting and mechanical processes.

But I can't find a reference that uses the term "sublimation" to describe the change from snow to ice in a glacier. The most common term is recrystallization (change in crystal structure) as the air is squeezed out and the snow crystals are broken up and then reformed into larger ice crystals. This takes place due to pressure and temperature.

TCD said:

Sublimation takes place on glaciers as part of ablation (overall loss of material). Ablation also takes place due to melting and mechanical processes.

But I can't find a reference that uses the term "sublimation" to describe the change from snow to ice in a glacier. The most common term is recrystallization (change in crystal structure) as the air is squeezed out and the snow crystals are broken up and then reformed into larger ice crystals. This takes place due to pressure and temperature.

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The overall process is often called metmorphosis. Recrystalization can be result of sublimation and condensation (ie without liquid), melt-refreeze (ie without vapor), by a process involving both liquid and gaseous water, or any combination over time.

Doug

Thank you all....i find it fascinating.