I think GRR went go down for almost two months last year (mid-Jan to mid-March), but it usually has an annual refurbishment in the winter. I just glanced at the Disneyland.com operating calendar and it's still on the closure list through the 15th, but it's not on the list for the 16th or 17th. That being said, the operating calendar is never terribly reliable for that type of information this far out.