A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
Winter Storm says: Until the end of the game, after each time an attack is declared, each player targets two of his unbowed Personalities with a Gold Cost eqal to or less than his Stronghold's Gold Production plus 2. Bow them.
What happens if this event shows up twice? Does everybody have to bow four of his unbowed personalities?
Yes effects of several Winter Storms are cumulative. If two different players have resolved their own Winter Storm, after each time an attack is declared, each player has to target and bow four of his unbowed Personalities with a Gold Cost eqal to or less than his Stronghold's Gold Production plus 2.