Soical Security is not welfare. Food stamps are welfare. Generally, when it comes to welfare all income is considered but you can check with your local legal aid office to be sure this answer is correct.
THESE COMMENTS ARE NOT LEGAL ADVICE. They are provided for informational purposes only. Actual legal advice can only be provided after consultation by an attorney licensed in your jurisdiction. Answering this question does not create an attorney-client relationship or otherwise require further consultation.
All income and assets can affect food stamps. The month the back pay comes in is income. Anything left over the next month is an asset. It must be reported to the food stamp office. Depending on the formula applied, the back pay may reduce or eliminate your food stamps. However, once that back pay is paid down to the exempt amount (usually $2000) or less, the food stamps will not be effected. However, your monthly pay may also affect the food stamps.