Anthem has postponed the Cataclysm, but you can still try the event out now on the game's new Public Test Servers on PC. EA and BioWare opened up the PTS today to let players test out changes to the game ahead of time, starting off with the world-changing Cataclysm event. Everybody who owns Anthem for PC (or is subscribed to Origin Access Premiere) is eligible to join the server; console versions aren't likely to arrive in the future, as is the case for most multiplayer games with public testing components.
If you can play, you're already "in" - no registration necessary. Just load up Origin and find the new Anthem PTS tile in your game library, then install it. Don't worry about getting your loadout just right before you start testing, as your character and progression won't carry over in either direction. You'll start at level 30 with all four Javelins unlocked and a starter set of gear "so you can focus your time and attention on the Cataclysm itself" as BioWare explains.
The Anthem Cataclysm event will go beyond nasty weather conditions; BioWare says there will be new areas, difficult foes, and… well, yes, "the deadliest weather events the world of Anthem can throw at you." I know Anthem is full of strange and alien things, but now I'm just picturing a squad of Freelancers being knocked out of the air by hailstones the size of bocce balls.
It sounds like the Anthem Public Test server won't be online at all times, just when BioWare has something big to put in front of a smaller subset of players. As a side benefit, this seems like the perfect time for lapsed players to pop back in and see if the future of Anthem looks bright enough to recommit.
What we know of the EA E3 2019 plans doesn't include Anthem, but EA could always sneak some more announcements in under the wire. On an unrelated note, here's a video explainer for why we love petting dogs in games.