Heroic Hagara 10 Tanking Guide

As usual, this isn't meant to be a complete guide. I assume you already know the basic mechanics of this fight and everything here is mostly geared toward tanks.

Changes Between Normal and Heroic

• Everything hits harder.
• Ice Lance increases frost damage taken by 25% per hit, instead of reducing attack speed.
• Ice Wave moves faster and there is a new snare debuff that needs to be properly taken care of if you want to stay ahead of the wave.
• There are 8 Crystal Conductors to overload in the lightning phase. You need 2 people between each conductor to overload them.
• You need to avoid Storm Pillars during the lightning phase, which leave a runic circle on the ground before they erupt for a large amount of nature damage.

Preparation

• One tank. Three healers if you have very good dps, but also possible with two.
• Physical damage reduction elixirs/flasks (agi flask for druids) or stamina flask.
• Tanks should think about using Stay of Execution to help mitigate Focused Assault.
• Leatherworkers should prepare some Drums of Speed. They come from a TBC rep, but require only honored and are very easy to make. Similar to the TBC haste drum rotations of old, we did the same with the three leatherworkers we had. It's also only a party-wide buff, so organize your groups accordingly. This is the macro I used. It announces when your drums begin and, more importantly, announces when they end so the next person can use their drums.

#showtooltip Drums of Speed
/p Drums of Speed used
/use Drums of Speed
/in 30 /p Drums of Speed over

Focused Assault 

• The big damage ability that tanks and tank healers should look out for.
• Happens about every 30 seconds that the boss is active.
• Cannot be dodged or otherwise mitigated (except by Savage Defense and Blood Shield), so if you repeatedly die to it, that's a sign you need more health.
• Unlike in normal mode, you can't consistently avoid the damage by running away, as she will follow you much more quickly. However, there are some opportunities where you can distance yourself from the boss if she is casting or collapsed, which will stop some of the damage. You will still have to take most Focused Assaults to the face.
• She will cast Focused Assault almost immediately after she activates. That means a few seconds after the pull and a few seconds after she recovers from collapsing. As long as your healers are aware of this, these attacks aren't so bad because they can be partially kited and the healers have no one else to heal. I recommend using lesser cooldowns (Barskin, Stay of Execution) for these first attacks.
• The Focused Assaults that you should save big cooldowns for are the ones during the Ice Tomb activation. Healers might be out of line of sight of the tank, or they might be healing other people.
• Healers should also be prepared to use their cooldowns on the tank.

Shattered Ice

• We could not explicitly confirm this, but it is commonly believed that Hagara will only cast this ability on people 180 degrees in front of her.
• This means that as the tank, you should drag the boss so that no one except you is near her front half. Because of the Ice Lance ability, this means you will be moving quite a bit.
• To get an idea of how strict this is, you can watch my video above. At 6:25, you'll see that there are people on her side, which is close enough for the priest to get annihilated by Shattered Ice. Don't let that happen.

Druid Specific Stuff

• If you're having trouble surviving Focused Assault, try using stamina trinkets and reforging to mastery. Since you can absorb Focused Assault hits with Savage Defense, you can help out your healers quite a bit by increasing your absorbs. The extra stamina will give your healers more room for slow reactions.
• Druids of any flavor are useful for Stampeding Roar. Just keep in mind that feral druids and other druids specced into Feral Swiftness will dispell their debuff if they happen to use it at that time. The best place to use it is if you see a few people falling behind.
• Tanks should go cat during ice phase, bear during lightning phase. 
• Spend the first few seconds of Hagara's collapsed phase dpsing in cat, but don't push it too far. You will get trucked if you happen to be in cat form when she recovers, and you also want to have all the appropriate tanking debuffs up before she casts her initial Focused Assault.
• For ice phase, if you're about to be forced off a crystal due to an upcoming wave, use your remaining combo points on a Rip (as long as savage roar still has lots of time left).  Even if it's just a 3 or 4 point rip, it's better than wasting combo points and doing zero damage.
• Use your Tier 13 4-piece Frenzied Regen during Lightning phase (unglyphed). Even though you will be rage starved, people going out of range of the healers is a real problem here, and your 3k per second will help a ton.
• Berserk can be useful during the collapsed dps burn phase, but since you can't spend all the time in cat, it might be better to use it during an Ice Tomb phase, where you can Mangle down three targets at once.