Editing v0.34:Glacier

{{Quality|Exceptional|15:49, 12 May 2013 (UTC)}}
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'''Glaciers''' are extremely cold [[biome]]s, usually found in the northern or southern extremes on larger world maps. The first few layers of any glacier are solid [[ice]].

There are few resources on an ice tile; no [[tree]]s, [[plant]]s, [[water]], [[animal]]s, [[stone]], or [[ore]]s are typically included. In addition, the [[ice]] can be several z-layers thick, which can make getting to any stone underneath even more challenging.

The lack of soil layers on a glacier combined with freezing temperatures means that above ground farming can not be practiced on them. This also means that by embarking on a glacier, you will be totally unable to grow ''any'' of the aboveground [[crops]]. Your selection of growable produce must all be grown underground, and will be limited to [[sweet_pod|sweet pods]], [[pig_tail|pig tails]], [[dimple_cup|dimple cups]], [[cave wheat]], [[quarry_bush|quarry bushes]] and, of course, [[plump_helmet|plump helmets]].

These factors make a glacier a very difficult biome to build a successful [[fortress]] in, although many players try it as a challenge. 

Also, because of glaciers are often very isolated, it is entirely possible that you won't see a caravan from the Mountainhomes for anywhere up to 3 years. Migrants may be even more rare. On the plus side however, no hostile nations should bother you for a while.

== Starting on a Glacier ==

Take a lot of wood, food and drink. Consider bringing extra [[domestic animal]]s ([[dog|dogs]] are recommended, as are [[turkey|turkeys]] for their plentiful [[egg_production|egg yield]]) as an emergency food source, and/or to jump-start a long-term [[breeding]] program.

Depending on your level of trade dependency, wood cutters can have little use on a glacier. You may want to sacrifice your wood cutter and axe in favour of another miner and pick. However, be aware that wood is plentiful enough on glacial biomes if you can manage the caverns. Alternatively, if you're <s>a total wuss</s> looking for an easier experience, you can embark on a locale where a glacier overlaps a forested taiga to bolster your log supply.

[[Ice]] is everywhere, so read up on it before you make any major plans. One difference between regular ice and glacier ice that you may want to know before you head out is that, unlike ice from other biomes, glacier ice constructions and workshops do not melt when above ground in the "summer".  The disadvantage, however, is that it is more difficult to use the ice as a potential water source.  Note that mined out chunks of ice, when melted by being brought underground, will '''not''' produce usable water. {{Bug|360}}

=== Digging down to the rock layers ===

Due to a bug, down-[[stair]]s and up-down-stairs can't be carved out of ice if the layer immediately below the ice is stone. {{Bug|358}} This makes it impossible to get from the surface down to the stone layers by purely digging stairs. The easiest way to circumvent this is to [[construction|construct]] an up-down staircase from some of the ice you will probably have mined out in the space where you intended to dig one. Despite being on a non-ice layer, the staircase will not melt.

=== Farming and Getting Water ===
Since glaciers contain no [[soil]] layers you will either have to [[irrigation|irrigate]] or farm in caverns.  Water is required for the former approach, and is also needed at [[hospital]]s for cleaning and to give the wounded something to drink.  There are two ways to get water on a glacier.

==== Underground Pools ====
All regions of the world have vast underground [[caverns]] (unless the world was [[world generation|generated]] without them), and caverns almost always have large pools of water.  Further, if the pool abuts the edge of your embark area, new water will fill in from the edge, giving you an infinite source of water.  On the down side, it can take a while to find the caverns, since digging straight down isn't guaranteed to breach them, and there's a small chance of aquatic monsters escaping from the cavern, or worse, not being able to find any water.

The "quick-and-dirty" approach that springs to mind for this is to simply dig one z-level above the water and build a well, but beware that aquatic beasts can and will climb into your fortress through your well, and worse, unless the pool is at least 2-z deep, the water will be laced with mud. The approach below allows for a safe, clean, sealed off reservoir.

To safely (without having to wander around inside the cavern) tap into an underground pool, consider the following diagram:

{{diagram|spaces=yes|\
WWWWWWWWW
▓▓▓▓X▓▓▓▓
▓▓▓▓B▓▓▓▓
▓▓▓▓.▓▓▓▓
▓▓▓▓.▓▓▓▓
▓S......▓
▓.......▓
▓.......▓
▓.......▓
▓.......▓
▓F▓▓▓▓▓▓▓
}}

* W = water
* ▓ = stone wall
* X = last wall to dig out
* B = floor with [[floodgate]] or [[bridge|drawbridge]]
* F = wall or optional floor with floodgate (for [[irrigation]])
* . = floor with optional paved [[road]]
* S = up stairs or ramp

Then do the following steps:

# Dig down to the same level as the pool (not to the surface of the pool) and dig out the reservoir (rectangular region) with stairs (or ramp) leading out.   
# If you're going to use the reservoir for [[irrigation]] then dig an outlet from the reservoir at the F, install a floodgate at its mouth, and hook it up to a [[lever]].
# Dig a tunnel to the pool, leaving one tile's worth of stone between the tunnel and the water (the X in the diagram).
# Install a [[floodgate]] or a south-raising [[bridge|drawbridge]] at the end of the tunnel and hook it up to a lever.
# Have a dwarf dig out the X.

The dwarf who dug the X should be able to get back to the stairs/ramp in time to not [[swimming|drown]].  To make extra sure of not drowning, ensure at least one dwarf is idling and have him/her pull the lever to the floodgate/drawbridge as soon as the wall is breached, then lower it again to let the reservoir fill.  To make extra, ''extra'' sure, embark with a dwarf with a single point in the [[swimming]] skill, and have him/her carve the fortification.

Use a drawbridge instead of a floodgate at the end of the tunnel to prevent [[building destroyer]] aquatic/amphibious monsters from swimming into the reservoir and enter the rest of your fortress.  A floodgate wouldn't stop a building destroyer, and monsters can swim through fully submerged [[fortification]]s. {{Bug|3327}}  If you're going to use this reservoir for a [[well]] then closing off it off with a drawbridge is very important, since some building destroyers can swim ''and'' fly.  If you're only going to use it for irrigation then you can use a floodgate and then simply [[wall]] off the reservoir once you're done with it, since building destroyers can't affect walls.

If you're going to use the reservoir for a well you should cover its floor with a paved [[road]] to prevent [[tree]]s from growing, because in some circumstances trees can grow underwater. {{Bug|1139}}

==== Dwarven Ice Cutting ====

This may not work, beware.

One quirk of [[dwarven physics]] is that a [[cave-in]] will transform an ice [[wall]] into liquid water.  This can be used to generate water in the following fashion:

To begin, it is best to clear out a large section of the rock underneath all the ice.  Then cut out a 6x6 section of ice (it is easiest to cut out two squares around the part you want to drop so that you won't have any fatalities while channeling out the section of ice).  Channel out the entire piece of ice and it will fall into that cleared out section, immediately defrosting and flooding the area.  Now you can farm!

Before you run out of starting booze, do the same again, but this time do it further away and open 3-4 levels of rock (channel everything away) so that you create a well.  Make sure you make it deep enough or you will create an ice zone that will kill any dwarf that tries to dig it out.  

Continue to cut out chunks of ice, dropping them a few stories, and reaping the benefits as you continue in the fortress.  Be careful channeling as the dwarves are all idiots and like to strand themselves while channeling, and they like to drop their buddies down the hole (which pollutes the future water and creates a huge mess).

Diagram of Ice cutting:

{{diagram|spaces=yes|\
OOOOOOOOOO
OCCCCCCCCO
OCIIIIIICO
OCIIIIIICO
OCIIIIIICO
OCIIIIIICO
OCIIIIIICO
OCIIIIIICO
OCCCCCCCCO
OOOOOOOOOO
}}

O = Open area, no channeling, just an area for dwarves to walk

C = Channel area, first dig it out, then channel once every layer is ready.

I = Future water source, now ice.

Once you have dug deep enough to see rock, channel out the entire level (make sure you have an escape route for the miner).  Also, when channeling a large room, do it layer by layer.  Start at the one end and do the entire left side, then the next.  If you just select the entire thing dwarves will die.

Don't drop water anywhere near other tunnels; the ice will break through, and it will be messy.  You can cut off entire sections of fortress to flooding or caved-in sections by doing this, and it wastes a lot of work and ice.

==== Other Approaches ====
[[Aquifer]]s are sometimes present on glaciers, and magma can be used to melt ice (although the only [[magma_sea|reliable source]] of that is very deep underground). Seaside glaciers can allow you to bring some water in underground, but [[Water#Salt_water|desalinating]] the water will be necessary before it is drinkable by dwarves (or even before it can be designated as a [[Activity_zone#Water_Source|water zone]] for filling ponds).

Beware that flowing sources of [[water]], such as [[river]]s or [[brook]]s, don't ever seem to be present in glacier [[biome]]s.

== Trade ==
Trade on glaciers is an issue of contention for some glacial Dwarf Fortress players.

Some players argue that trade is basically essential on a glacial biome. Anyone playing on a glacier will inevitably end up with a lot of rock, so a commonly suggested source of income is rock [[crafts]]. However, beware that ice ''cannot'' be used to make crafts, even if the craftdwarf's workshop is on a z-level with freezing temperatures that would keep the ice from melting. The majority of your imports will be wood, used for making beds and other necessities, as well as fuel for making metal objects.

However, also be aware that independence from trade on a glacial biome '''is''' entirely possible. It does require extra effort and careful rationing of certain materials, but it can be done.

=== Glacial Independence ===
Gaining independence from trade on a glacier is a difficult prospect, primarily because of the lack of wood to be found on glacial biomes. However, even though wood is commonly used in the creation of various constructions and tools, it is almost entirely replaceable with either stone or metal crafting. However, there are two wood-based needs in Dwarf Fortress that are trickier to circumvent: beds and fuel.

==== Beds ====
The need for wood in the construction of beds is unavoidable: no other material in the game can be used to make them. However, that is not to say that trade is the only thing that can supply wood. The answer here lies in [[caverns]]. Caverns grow trees on their soil constantly, and if correctly managed, can be turned into [[tree_farm|tree farms]]. However, the trade-off is that to supply wood for beds early, aggressive expansion into the caverns will be required, which can be extremely [[fun]]. In light of this, it is recommended to bring at least seven logs with you on embark to build beds for your first seven dwarves, and to read up on [[caverns]] and their [[Giant_olm|dastardly]], [[Troll|dangerous]] [[Crundle|darting]] [[Cave_crocodile|denizens]].

==== Fuel ====
[[Fuel]] is a different matter; wood does not have to play a part in its production. If you are very lucky, you may find [[bituminous coal]] or [[lignite]], the two stones which can be turned into fuel for metalwork, but the odds are that you will have to do without. For this, your best option is to get down to the [[magma sea]] as soon as you can to build magma-based [[smelter|smelters]], [[forge|forges]] and the like, or at least as soon as you need to start using metal. This has the added advantage of quite possibly leading you to discover additional caverns (and thus sources of wood and water) along the way.

Needless to say, read up on [[magma]] before attempting this. Magma's usage can lead to an awful lot of unexpected [[fun]] in inexperienced hands. Also take a look at the [[magma_crab|various]] [[fire_imp|other]] [[magma_man|hazards]] that can confront anyone working with the magma sea, and consider channelling some of the sea into a reservoir or using a [[screw_pump|pump]] to isolate your working dwarves from them. Once you have got the hang of it, magma really is a blessing because of its lack of limitations; the magma sea is not about to "run out" of magma, and it also makes for good <s>[[elf|hippie]]</s> [[refuse|garbage]] disposal. Also, if you are very lucky indeed, you may well stumble across [[adamantine|something special]].

== Wildlife ==

'''On neutral glaciers appear:'''

* [[Polar bear]]
* [[Yeti]]
* [[Weasel]]

'''On evil glaciers appear:'''

* [[Blizzard man]]
* [[Ice wolf]]

== Notes ==
Ice that is underground melts, but creates only useless puddles of water (marked as a cyan double tilde) identical to water dumped from a [[bucket]].  These puddles can only be cleaned.  They cannot form usable water (blue tilde with depth attribute).  Dumping block after block of mined ice blocks indoors will simply result in a huge stack of useless "water".

Glaciers are very unlikely to have a source of [[shell]]s.  Thus, you may want to mod the game so that some other material can be used in place of shells for the occasional [[strange mood]]s which call for them; see [[Shell]] for details.

Some glacier biomes have such low temperatures that your dwarves and animals may die if exposed aboveground for too long.

Water in [[bucket]]s does not freeze above ground so you can designate an area as a pool, tell dwarfs to fill it, then smooth and engrave your new ice fort.

== Volcanoes and Glaciers ==
If you embark on a Glacier Biome with a Volcano you might think it would be a good idea to erupt the volcano (dig a hole into its side) onto the glacier ice. This will indeed cause some interesting effects like multiplying the amount of ice, casting obsidian and spamming you with cavern" collapsed" messages. The ice will expand due to the fact that one molten wall of ice will become 7 units of water, potentially flowing apart in all directions and freezing into new walls of ice immediately, which can then melt into 7 ''more'' units of water. If the water flows to the same square as the magma it will turn to obsidian. Both the ice and the obsidian walls may not be connected to another solid wall so a lot of cave-ins will occour.

{{World|Biomes}}