NWS has used tablets and a GIS system for years to do storm damage surveys. When reading a storm writeup on one of the WFOs pages, I found they have now exposed read only access to the general public: NWS Damage Assessment Toolkit
The Damage Survey Viewer that you link to has been available for a few years (at least). I guess I sort of assumed everybody knew about it. As an "experimental" product, I am pretty sure not all surveys make it into that viewer, but, still a good resource.