Still speculative, but preliminary estimates are 40,000 to 50,000 copies of video lost in the fire.
I haven't heard for sure, but the video assets may have been largely dub masters used for fulfilling dub requests from their domestic and international client TV stations who broadcast Universal's many syndicated TV shows. If that's the case, then no, master copies would not have been housed in the same locationspecifically for this type of scenario, but they will be busy for quite some time creating replacement dub masters.
Don't most studios use climates with hardly any change for storing the original master copies. Such as deep underground salt mines where humidity and temperature barely fluctuate.