Firestorms in The Waking Shores

All the pheonix advices are valid, but we found a great spot at Scalecracker Keep .
At first I thought there are no mobs how do we do this? But then I found a hut at /way 66.76, 25.70 and they respawn like crazy.
We were in 2 people, 1 underground level other one on the ground level and we got the achievement done in 10 minutes. Even solo it would be a quick farm.
Non elites, quick respawn, can recommend this spot.

The birds are your friends for all the Storms!

Any bird that drops a feather on being killed and then rises again to be killed again counts as TWO KILLS towards these achievements. Don't kill the feather!

For the Obsidian Citadel, there are Lava Phoenix and Lava Hatchling.

For the Scalecracker Keep, there is an elevated rock with a bunch of Lava Phoenix on it at 20.3, 52.4. (There are a couple Blazing Dreadsquall there as well.)

The worst of the bunch. If you are doing this one next to Dragonbane Keep, expect 80% of the mobs to not count towards the achievement. Ridiculous place with very few mobs, and it's "blended" with regular fire mobs that don't have the primal storm effect.