The second episode of "The Lord of the Rings: The Rings of Power" centers on an epic storm in the Sundering Seas. Pulling it off involved a method that has become Hollywood's go-to approach for creating storms at sea: filming the sequence in a giant water tank. Outdoor water tanks have become a staple of productions big and small seeking to recreate scenes of violent ocean storms — from Kumeu Studios in New Zealand, where "Rings of Power" filmed its storm, to Pinewood's horizon water tank in the Dominican Republic, where films like "The Lost City" (2022) and "Old" (2021) have shot aquatic scenes. Tanks allow filmmakers to exercise exacting control over the conditions of a seemingly chaotic scene, whether a tempest like that in "The Rings of Power" or a tidal wave like that in "The Impossible" (2012). Helming the storm in "Rings of Power" were J.A. Bayona and Óscar Faura, the director and cinematographer who previously recreated the 2004 Indian Ocean tsunami for "The Impossible" at Ciudad de la Luz Studios' massive seaside tank in Spain. The director-DP duo joined a team of expert storm-makers that included special effects supervisor Dean Clarke, who helped create the ocean hurricane effects in "Adrift" (2018), and ILM, the VFX studio behind scores of water- and storm-heavy movies, from earlier films like "Deep Impact" (1998), "The Perfect Storm" (2000), and "Poseidon" (2006) to the massive maelstrom in "Pirates of the Caribbean: At World's End" (2007) and the biblical deluges in "Evan Almighty" (2007) and "Noah" (2014). We spoke with Clarke along with producer Ron Ames, who oversaw VFX and postproduction for "Rings of Power," and senior VFX supervisor Jason Smith, who coordinated the series' extensive digital effects work. We also talked to Bolívar Sánchez, the marine and underwater coordinator for Pinewood's tank set, about how productions achieve key storm shots in water tank sets while prioritizing safety and control. "Rings of Power" filmed the underwater portions of its storm in an immersive dive tank at the same facility in New Zealand. In the larger tank, the team used a combination of construction diggers, dunk tanks, pyro, switchable backgrounds, a gimbal-controlled raft, and a retractable roof to create a swirl of water and weather effects. They paired these practical techniques with subtle VFX that added CG waves, streaks of froth, and digital lightning bolts. Ultimately, the sequence used a 50-50 split between practical and digital effects. For more of "Rings of Power": https://www.amazon.com/Lord-Rings-Power-Season/dp/B09QH98YG1 For more from Dean Clarke: http://www.dcspecialeffects.co.nz/ For more from Pinewood DR Studios: https://lantica.media/ www.instagram.com/lanticamedia