academic job offers during Coronavirus I signed a contract for an academic faculty position in the US in February. Now with the pandemic affecting universities, do you think it is possible that they rescind the offer? Is it appropriate to reach out to the dean or someone else and ask how the situation is developing in light of hiring freezes at some universities in the US?
Yes, it is appropriate to explore the situation. I doubt that the offer would be rescinded, but who can say except them. They will need the personnel now as much or more than ever. 

You have a signed contract so they are bound as well in all but the most extreme situations. 

But timing and such might be disrupted. And if you aren't already in the US, note that border crossing is very difficult if even possible. 

But ask, and ask to be kept informed.