Hivernal

The Hivernal is one of the ten high dragons encountered in Dragon Age: Inquisition. It can be found in the east area of Emprise Du Lion. To access the area requires completing the Restore Judicael's Crossing war table scouting operation. It can be found in the first ring across the bridge: Etienne's Ring.

Note: It is recommended to pick up the quest Breeding Grounds before going after the Hivernal, as the quest cannot be started if one of the 3 dragons involved has been killed before obtaining it.

Strategy

The dragon's stats are as follows:

Level 18 Boss

226288 HP (Nightmare difficulty)

59 Armor

Greater Cold Resistance

Fire Vulnerability

Immunity: All Disabling Effects

Immunity: Slowed

Perceptive

The Hivernal breathes ice instead of fire, dealing cold damage. The dragon is resistant to cold damage, but vulnerable to fire. Bringing Ice resistance potions is a must on higher difficulties, particularily for your tank. Regeneration potions can also help, as can Antivan Fire grenades. Equip your mage or mages with an fire staff. Dragon-Slaying and fire runes can also help somewhat, but it's not required.
The Battle against the Hivernal is almost identical to the one against the Greater Mistral in the Emerald Graves. The only difference is that The Hivernal will not generate a guard bar at regular intervals like the Greater Mistral will. The Hivernal is however 2 levels higher.

The Hivernal will stay on the ground for most of the fight. She will make small "jumps" to cover distance at times. During the battle, at 75%, 50%, and 25% health, she will take off. Shortly after, she will return at high speed, breathing Ice bursts at party members along her path, which will chill (slow) and damage them. Shortly after she will land, knocking any party members there off their feet and doing high damage to them. Spreading your party out when she takes off is a good idea. Abilities like Evade, Fade Step and Combat Roll will be useful to keep your party members out of harms way.

All dragons will often attack any party member close to her with melee attacks. She will signify a melee attack by raising the leg closest to the party member she will try to hit, avoid it with Fade Step/Evade/Combat Roll. Getting close to her tail will often make her raise her tail up and to the side in preparation to swipe the whole area behind her. A tail swipe is harder to avoid than an attack with her legs since it will cover a larger area, the best thing to do is to stay away from her tail.

Every time the dragon lifts its wings high up over her body, she's about to use her "Maelstrom" ability, an ability all or nearly all dragons in the game have. She will flap her's wings 4 times, and every time, she will suck your party closer to her and do high damage to them. The ability has a extremly long range so it's doubtful you can outrun it. There are 3 ways to deal with this ability:

With high enough dps you can just weather it, since you will see this ability no more than a couple of times. Nuke the dragon down, popping potions, although you will burn through them quickly.
You can hide behind obstacles. This can be difficult because of poor Ai pathfinding, AI unwillingness to stand where ordered even when "holding position", dragon constantly moving and destroying obstacles.
Lastly, and the best way, is to get into melee range (inside the maelstrom circle). Inside it you will take no damage. As soon as you see the dragon's wings rise high, use your Evade (Rogues) & Fade Step (mages) to help get them inside the circle as fast as possible. Having your ranged party members stand not to far from the dragon at all times will help prepare for the maelstrom. Your melee companions will already be where they should. When the dragons stops flapping it's wings, get your ranged party members out again quick, so they don't get hit by the dragons melee attacks.

The Hivernal will also use her Ice Blast ability if a party member that is not in melee range has aggro. She will shoot a ball of ice in a straight line which will explode on the ground and leave a cloud of frost for a while. Any party member that walks over this, will take damage and get chilled (slowed). Sometimes she will jump away from the party intentionally to use this attack. Avoid this ability with Fade Step/Evade/Combat Roll.

The Hivernal will also use it's Ice Breath ability at times, she will signify this ability by raising her head back and up. She will then spray the ground in front and to the sides of her, trying to seek hitting any party members that are standing close enough. The breath will leave party members chilled as well as doing damage to them. Avoid this ability with Fade Step/Evade/Combat Roll.

Focusing your party's damage on the dragons legs can make the dragon fall to the ground helplessly for a short while when you have damaged all four legs enough. A dragon which has a damaged leg will be bleeding severely from it. It will also show a "pain" animation and jump away if you have damaged a leg enough. Focus your damage on one leg at a time, after you see that leg start to bleed, change to another leg. When the dragon is lying on the ground, it is a very good time to use many of the party's ground-targeted focus abilities, like the Inquisitor's Mark of the Rift or Solas' Firestorm, since you know the dragon will not move for a short while. Typically it will take a very long time to damage the dragons legs enough for it to fall, often taking almost the whole battle for it to occur.