Oops. I forsee emergency after emergency. Revise to say 3/4's vote of Congress to declare an emergency and sunset in one year time frame.
VRW Conspirator,
The additional clause you suggest seems fine and in order.
But realize that Congressional declarations of catastrophe occurring within a State will in no way authorize the Congress to lay and collect additional taxes. If Congress declares a catastrophe (whether by simple bicameral majority or super bicameral majority) at that point they can grant a tax exemption, deduction, or credit to the State under strain. So there is no motivation for even a plurality (or even a sizable minority)of representatives to give a State a big ol’ honkin’ tax break. That doesn’t put revenue in their US Treasury - it takes money out.