From the now defunct "Mandatory Purchase of Flood Insurance Guidelines":
The statutory requirements apply when improved real property (that is, a building) or manufactured (mobile) home is taken as security for a loan.
Is there a loan? You stated the Bank owns the property now due to foreclosure. If the property in the SFHA is now OREO, it is a bank asset, so your obligation to have flood insurance comes from a safety and soundness perspective, not compliance.