In general, both spouses are responsible for mortgage debt incurred during the marriage, regardless of who incurred the debt. However, the specific circumstances of a natural disaster may affect this responsibility. Consider the following factors:

1. Community property: In community property states, both spouses are typically responsible for debts incurred during the marriage, including those resulting from a natural disaster.

2. Joint ownership: If both spouses own the property together, they may both be responsible for the mortgage debt, regardless of who incurred the debt.

3. Insurance coverage: If the property was damaged or destroyed during a natural disaster, insurance coverage may help pay for repairs or rebuilding, reducing the mortgage debt.

4. Government assistance: Government programs may offer assistance with mortgage payments or debt forgiveness after a natural disaster.

5. Divorce agreement: The divorce settlement agreement may address how mortgage debt incurred during the marriage, including during a natural disaster, will be divided and paid.

6. Court discretion: In some cases, the court may consider the circumstances of the natural disaster and the spouses' individual circumstances when determining responsibility for the mortgage debt.

To determine responsibility for mortgage debt incurred during a natural disaster, consult with an attorney specializing in family law and financial matters. They can help you understand your specific situation and negotiate a fair division of assets and debts in the divorce agreement.