42 USC 5162 - Advance of non-Federal share

(a) In general 
The President may lend or advance to an eligible applicant or a State the portion of assistance for which the State is responsible under the cost-sharing provisions of this chapter in any case in which
(1) the State is unable to assume its financial responsibility under such cost-sharing provisions
(A) with respect to concurrent, multiple major disasters in a jurisdiction, or
(B) after incurring extraordinary costs as a result of a particular disaster; and

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(2) the damages caused by such disasters or disaster are so overwhelming and severe that it is not possible for the applicant or the State to assume immediately their financial responsibility under this chapter.
(b) Terms of loans and advances 

(1) In general 
Any loan or advance under this section shall be repaid to the United States.
(2) Interest 
Loans and advances under this section shall bear interest at a rate determined by the Secretary of the Treasury, taking into consideration the current market yields on outstanding marketable obligations of the United States with remaining periods to maturity comparable to the reimbursement period of the loan or advance.
(c) Regulations 
The President shall issue regulations describing the terms and conditions under which any loan or advance authorized by this section may be made.