Thunder Valley is a 18 vs. 18 Scenario in Tier 4 Greenskin vs. Dwarf. Anyone between levels 32 and 40 can join this Scenario. Information is from Warhammer Online Scenario 101 Episode 8
The terrain for Thunder Valley is quite large and features 5 capture locations: The Gyrocopter Hangar, Fireball Mortar, Gungnir's Fist, Blasting Cart, and Firing Range. Taking any of these locations will grant your Realm points towards winning the Scenario and continue to give you points as long as you hold them.
From the spawn points in this Scenario, you can charge straight ahead to the Gyrocopter Hangar. Beware players with knock-back abilities around the Hangar as it's surrounded by lava and narrow bridges! Head right or left from the spawn area to access the other capture locations. Fireball Mortar overlooks the Gyrocopter Hangar, while Gungnir's Fist is an enclosed area surrounded by large walls and keep ruins. Blasting Cart and Firing Range are elevated positions accessible from only two directions.
The most notable aspect of Thunder Valley is the siege weaponry you'll employ to help win the Scenario. When you hold any of the capture locations, siege weapons will spawn giving you new offensive and defensive capabilities. However, watch for incoming siege attacks from other capture points. If you take the centrally located Gyrocopter Hangar, you'll have to defend against attacks from several directions at once, but have the best offensive positioning to assault other capture locations. Capturing Gungnir's Fist or Fireball Mortar gives you the ability to defend against assaulting players, but limited offensive firepower to help take other capture location.
Thunder Valley requires a lot of team work and roving patrols by players. You'll need to have your mount ready for fast travel to attack and defend capture locations as they're sure to switch hands often in this multiple-capture Scenario!
External Links Edit
Link Below to Warhammer Online Scenarios Episode 8. 
Thanks to the Game Makers for providing such detailed documentation. TimJG 23:58, 22 November 2008 (UTC)