Check out the Sindragosa section on our Icecrown Raid Information page. It'll give you an overview and help familiarize you with the various abilities and attacks she has. Again, this article is aimed directly for healers who might be suffering from various parts of the encounter or are just looking for tips to get by. Start off with six healers and plead with your tanks to pick up some frost resistance gear. It helps a ton against her Frost Breath.
As most dragon encounters go in the game, this happens to be her ground phase. There are a few things to be careful of.
Unchained Magic: It's an extremely annoying debuff. When you cast spells, you gain an Instability debuff. The more stacks of Instability you have, the more damage you take when the stacks wear off (caused by Backlash). I personally like to go up to about 5-6 before letting it wear off. However, when you're in the early phases, it's good to stretch yourself and see how far you are willing to push that limit in case you need to unload some major healing. Try to time a big heal (such as Prayer of Healing or Holy Light) to land just as Instability wears off.
Blistering Cold: Heh, I think ability alone will be a big reason why most raid groups will wipe. She'll pull everyone directly on top of her with an Icy Grip before she unleashes an AoE nuke that will kill almost anyone standing within the blast radius (except a tank). When she pulls you in, stop what you're doing and just run away. Ideally, you'll want to practice running toward the stairs but when starting out, simply focus on getting away from her. I picked up Body and Soul just to run away quicker or to cast it on someone who I'm not sure will make it. It seems possible to resist the Icy Grip, but my results haven't been consistent. Sometimes I don't get pulled in but in other cases I do.
Frost Aura: Uh, just keep healing. Everyone in the raid will be taking damage.
This is the air phase. She flies away and becomes out of reach for the raid. She'll start tossing out Frost Bombs. Players can typically survive one Frost Bomb blast but it's highly recommended that they use the Ice Tombs to to shield themselves. I like to have my entire raid gather up at the base of the stairs that lead to the main platform. Once the Frost Beacons have hit, the players that have not been marked generally run up the stairs and get far away. When the beaconed players become Ice Tombed, any players that happen to be around them will get hit as well. Run up to and hug the Ice Tombed players. Make sure the blocks are between you and the location of the Frost Bomb that Sindragosa throws out. As healers, if you can chip in DPS on the blocks, I strongly suggest doing so to help accelerate the process in 25 (it might not be necessary in 10s). But make sure players that have been hit by bombs are topped off first.
It's really easy to see where the next Frost Bombs will hit. Look for the swirling thing on the floor. You have several seconds to hide behind a block before it lands.
Get some heals ready for the players that are emerging from the broken out blocks. I suggest using instant cast spells if they're in danger of dying. Sindragosa will land after she fires off her 4th bomb. She'll continue to repeat phase 1 and 2 until she reaches 35%.
And here is the fun phase. Sindragosa doesn't take off in the air anymore. But she'll start casting Mystic Buffet on the entire raid. It stacks and steadily increases the amount of magic damage taken by the raid. Don't worry about unloading massive DPS on the boss. This phase is about your ability to survive and not panic.
We use two specific areas for players that get targeted with a Frost Tomb. Players get away from that player that's about to get tombed so that the ability isn't chained. Only one player will be under Frost Tomb. I would assign a raid healer specifically to heal up the player that gets marked. A discipline priest works perfectly. Hit them with a Power Word: Shield and Penance. You want to ensure that the entombed player survives getting hit. Once that player is tombed, run toward it and position it so that the block is between you and Sindragosa. Mystic Buffet will only be applied if you are in line of sight of the boss.
For healing the tank, I have 4 tank healers. 2 of them are on the tank at any given time. The team that heals the tank is the pairing that isn't hiding behind a Frost Tomb since they'll have line of sight with the tanks. The ones that are ducking behind tombs switch to maintaining the raid until the Frost Tomb they're hiding behind gets broken.
Have some tanking and defensive cooldowns ready. Hand of Sacrifice, Pain Suppression, Guardian Spirit and whatever cooldowns the tanks have available should be used before she unleashes a Frost Breath. You might want to consider setting up a pre-determined save order in advance.
Anyway, good luck! Phase 3 is a tough phase for sure and it will take many attempts and frustrations before Sindragosa goes down for good.
Want some more advice for working with the healers in your guild? Raid Rx has you covered with all there is to know! Need raid or guild healing advice? E-mail me at firstname.lastname@example.org and you could see a future post addressing your question. Looking for less healer-centric raiding advice? Take a look at our raiding column Ready Check.