Question: I usually use "glacial" to denote something as very slow-moving, but this time I am actually talking about a glacier so it can't be "the glacial glacier".

[These](http://thesaurus.com/browse/glacial) are the synonyms of "glacial" (They all mean cold)

[These](http://thesaurus.com/browse/slow-moving) are for "slow-moving", but none seem to actually imply the persistent slow movement of a glacier.

Answer: 
Perhaps **[snail-like](http://www.collinsdictionary.com/dictionary/english/snail-like)**?

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> resembling a snail, esp in moving very slowly
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Also consider **[inexorable](http://www.merriam-webster.com/dictionary/inexorable)**

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> not able to be stopped or changed
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while it does not, in itself, convey *slow*, it could be coupled with *crawl*, which does.

**Inexorable crawl** sounds like a *glacier* to me.
* Gradually but surely we shall change the world.
* The gradual pace of the glacier took place over millions of years, to carve the canyon.

[gradual](http://www.thefreedictionary.com/gradual) [ˈgrædjʊəl]

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> adj. 
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> 1. taking place, changing, moving, etc., by small degrees or little by little: gradual improvement.
> 2. rising or descending at an even, moderate inclination: a gradual slope.
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> n. 
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> 1. a. an antiphon sung between the Epistle and the Gospel in the Eucharistic service.  
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>  b. a book containing the words and music of the parts of the liturgy that are sung by the choir.
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> [1375–1425; late Middle English < Medieval Latin graduālis pertaining to steps, graduāle the part of the service sung as the choir stood on the altar steps = Latin gradu(s) step, grade + -ālis -al1]
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