Water leak after Texas Freeze

[bspirito]

I have a flying cloud 26 u 2016. I attempted to empty grey water tank, which showed 100% full but the valve would not open. I had my doubts that the tank was full due to limited use the previous week.
At the campsite, I hooked up to city water. I soon noticed water on the floor of the coach and dripping from the rear compartment. I attempted to empty the grey water tank again. The value worked fine but virtually no water drained.
I have an appointment next week with an Airstream dealer in DFW but am curious if others have had similar experiences or may know what happened.

Thank you,
Brad Spirito