Note: Icecrown Citadel and patch 3.3 are currently on the public test realms. This information may change throughout the testing process!

Encounter Details

Sindragosa
 Health: 34.9m (25) / 9.76m (10)  Enrage: 10 minutes
"Phase 1" - Ground
Blistering Cold
Deals 35000 Frost damage to enemies within 25 yards. This is used after she casts Icy Grip.
Cleave
Inflicts normal damage plus 50 to an enemy and its nearest allies, affecting up to 10 targets.
Frost Aura
Deals 4500 Frost damage to all nearby enemies every 3 sec.
Frost Breath
Inflicts 37000 to 43000 Frost damage to enemies in a 60 yard cone in front of the caster. In addition, the targets' attack speed and chance to dodge are decreased by 50% for 6 sec.
Icy Grip
Extend tendrils of frigid wind to pull all nearby enemies to the caster. After she uses this, she will follow it up with a Blistering Cold.
Instability
Using magic while afflicted with Unchained Magic will build up unstable energy, dealing 2000 Arcane damage to the caster per spell cast, 8 sec after spellcasting ends. Stacks 99 times.
Permeating Chill
20% chance on physical attacks to be chilled to the bone, dealing 1000 Frost damage per 2 sec. for each application over 8 seconds. Stacks 99 times.
Tail Smash
Inflicts 11250 to 18750 damage on enemies in a cone behind the caster, knocking them back.
Unchained Magic
Inflicts an arcane malediction on the target, causing any spells cast to result in a backlash of Arcane power after 8 sec.  Multiple spellcasts by the afflicted target will intensify the backlash.
"Phase 2" - Air
Every so often Sindragosa will take off into the air. This is considered phase 2 for the encounter. She will target 5 players with Frost Beacon, and those players will then be placed into an Ice Tomb shortly after. From there she will drop 4 Frost Bombs at random locations in the room.
 
The goal here is to hide out of Line of Sight of the Frost Bombs -- similar to Sapphiron -- while damaging the Ice Tombs to break frozen players out. Don't kill the tombs too early, though, or you may take damage from a Frost Bomb!
Frost Beacon
Marks a target for imprisonment in an Ice Tomb.
Frost Bomb
Deals 23563 to 26437 Frost damage to all nearby targets. You need to hide behind Ice Tombs to avoid this damage. Sindragosa will target locations in the room while flying and cast it there. After she uses this 4 times she lands.
Ice Tomb
Entombs the targeted foe and all enemies within 10 yards in ice. She targets 5 random players after taking off and casts this on them. They are then trapped in a tomb with 454k HP which must be killed. These tombs also block Line of Sight on Frost Bomb, but anyone inside the tomb has Asphyxiation placed on them.
"Phase 3" - 30% Health
At 30% health Sindragosa enters what could be considered a "soft enrage," causing the fight to become a bit more hectic. She no longer takes off into the air, but instead begins casting Ice Tomb on random targets.
 
In addition, she casts a new ability called Mystic Buffet which increases magic damage taken with each application. This can be very deadly for the tank if the fight lasts too long.
 
Make sure to hide behind Ice Tombs to reset the stack of Mystic Buffet, as it can be blocked by Line of Sight similar to Frost Bomb in phase 2.
Blistering Cold
Deals 35000 Frost damage to enemies within 25 yards. This is used after she casts Icy Grip.
Cleave
Inflicts normal damage plus 50 to an enemy and its nearest allies, affecting up to 10 targets.
Frost Aura
Deals 4500 Frost damage to all nearby enemies every 3 sec.
Frost Beacon
Marks a target for imprisonment in an Ice Tomb.
Frost Breath
Inflicts 37000 to 43000 Frost damage to enemies in a 60 yard cone in front of the caster. In addition, the targets' attack speed and chance to dodge are decreased by 50% for 6 sec.
Ice Tomb
Entombs the targeted foe and all enemies within 10 yards in ice. During this phase she will target a random player and cast this on them. They are then trapped in a tomb with 454k HP which must be killed. These tombs also block Line of Sight on Mystic Buffet, but anyone inside the tomb has Asphyxiation placed on them.
Icy Grip
Extend tendrils of frigid wind to pull all nearby enemies to the caster. After she uses this, she will follow it up with a Blistering Cold.
Instability
Using magic while afflicted with Unchained Magic will build up unstable energy, dealing 2000 Arcane damage to the caster per spell cast, 8 sec after spellcasting ends. Stacks 99 times.
Mystic Buffet
Buffets all foes within 200 yards with arcane energy, increasing all magic damage taken by 10% per application for 8 seconds. Stacks 99 times.
Permeating Chill
20% chance on physical attacks to be chilled to the bone, dealing 1000 Frost damage per 2 sec. for each application over 8 seconds. Stacks 99 times.
Tail Smash
Inflicts 11250 to 18750 damage on enemies in a cone behind the caster, knocking them back.
Unchained Magic
Inflicts an arcane malediction on the target, causing any spells cast to result in a backlash of Arcane power after 8 sec.  Multiple spellcasts by the afflicted target will intensify the backlash.

Achievements

Below are the achievements Sindragosa is directly involved in so far.

Achievements
Sindragosa
PH in 10-player mode.
The Frostwing Halls
Defeat the bosses of The Frostwing Halls in Icecrown Citadel in 10-player mode.