Federal Code and Regulations typically require that Proofs of Loss for National Flood Insurance claims be filed within 60 days following the loss. They have to be done completely and on time. The only exception is a written waiver from the Administrator of the National Flood Insurance Program.
On October 20, 2008, a 120-day extension was issued. That extension was close to expiring, and on February 20, 2009, the NFIP Administrator issued an additional 90-day extension to file proofs of loss for Hurricane Ike and Gustav.
Flood policyholders now have a total of 270 days from the date of loss to submit their proof of loss. For example, a September 11, 2008, Ike-related loss must have a proof of loss submitted by June 8, 2009.
You can read the February 20, 2009, extension letter here.