Pbartender said:
First, I would not have had the kobolds wait until the PCs reached the top of the cliff. Hit them while they are climbing, and are at an obvious disadvantage.
I think this was the original plan (shame they were not kobold rogues rather than warriors, to have got the sneak attack goodness against climbers) but the party foiled it by flying & teleporting to the top.
I think if I had been running it then I'd probably have had the cleric cast a targetted dispel magic on the fighter as he was flying up and just as he reached the top, while the rage mage throws the lightning bolt down at the poncy elven wizards at the bottom of the cliff... try and get several people who would *really* be hurt by 10d6!
As others have said, I think an avalanche would have been the ideal trap for the bored kobolds to prepare - they would have planned to trigger it when the party were halfway up climbing, but when the fighter started flowing they would think that the gaff had been blown and trigger it right then. All the rest of the party would have been in the bury zone, and suckers for damage and pinning.
However, as Takyris said, this seemed to be an encounter which did its job - cost the party a few hps, used up a few of their spells, didn't seriously challenge the party.
The good news is that a couple of the kobolds got away - so they can report back on the PC threat, get together with others and the NEXT time the PCs confidently meet arctic kobolds they could find themselves in a lot more trouble (an encounter replete with traps and environmental problems as mentioned by other posters.
The Rat Bastards DMs Club (which includes Takyris, Nemmerle, Radiating Gnome & Pbartender who helped here, amongst others)
http://pub109.ezboard.com/faquerrafrm29 loves to help DMs to work out nasty combinations for encounters
Cheers