Since a short story is obviously limited as in terms of length, is it possible to still use a slow pace? Or do they necessarily need to be fast paced thoughout with hightened description?
Would you use a fast or a slow pace for a novel? Really, your question makes as little sense as that one. It depends entirely on the story itself. Some stories are slow, steady, creeping. Others are action-packed and heart-pounding. It depends on plot, on style, and many other things. Also, I'm not sure there's really a "max word count". The boundaries between fiction categories are less clear cut than that, and vary quite widely from market to market.
Use the pace that fits your subject?! Think back to the short stories that you were asked to read in school. I thought most of them were slow-paced and serious. Only "The Ransom of Red Chief" by O. Henry had any real speed to it, and that was to keep the humor going. Just because we write fantasy, mystery, or sci-fi doesn't mean we don't have the same rules (and freedoms) as the "great" literature.
i'd never even consider 'pace' when writing fiction, since each story would set its own... just write the story! as for length, the optimum for most print venues is around 5k or shorter... but each venue has its own limits, so write however many words it takes to tell the story and deal with limits when its finished... you can always make it a bit shorter or longer to suit your target magazines later...
Pacing is incredibly important. Bad pacing is what ruins most fantasy novels. An Australian author, Alison Croggon, wrote a fantasy series called Pellinor. I absolutely loved it because it had a brilliant plot-basis and had so much potential, but it was ruined by horrible clichés (the main character is the chosen one in an old prophecy, an orphan, starts as a slave in a faraway village place, carries items which are old and incredibly valuable but are also ordinary looking, she has incredible power with little training, and she isn't even fully human - she's part "elemental"). We find out all of that and more in the first novel. Way too much happens in that one novel, and it's not even in a short amount of time. It happens over about a month and a half. Pacing is very, very important, and it does require some thinking.
i didn't say it wasn't important... but ok, i guess i can agree that like other aspects of writing, it may 'require some thinking' for some [most?] beginning writers, but i think it comes naturally to most [if not all] seasoned ones... i'd be interested in knowing how many of the longtime or professional writers here ever think about or pre-plan pacing when they're writing a story/novel...