Here are the instructions from IRS:

The IRS automatically provides filing and penalty relief to any taxpayer with an IRS address of record located in the disaster area. Therefore, taxpayers do not need to contact the agency to get this relief. However, if an affected taxpayer receives a late filing or late payment penalty notice from the IRS that has an original or extended filing, payment or deposit due date falling within the postponement period, the taxpayer should call the number on the notice to have the penalty abated.