Rosalie and Rosalind were directly under a piece of Yosemite Station when the Shang brought it down all over Western America. It was a direct hit on the building they were in. Rosalind managed to get her sister out safely, but the building collapsed on her. Trapped her under tons of modern building materials that basically emulsified her body. She might have survived in the end if enough of her brain could have been transported to a hospital to feed and stabilize her. But the fires left… nothing. Just ashes. And even we don’t come back from destruction that general and complete. Rosalind died under all that destruction, and Rosalie lost the sister who had been at her side since before they were both born. She was utterly and completely devastated.