Hi all, thanks for the responses!! You can't use real chains on my Forester but you CAN use cable chains. Subaru even sells them in their parts department, but nobody around me stocks them.
I only need them for one or two trips a year to the mountains, so not really worth buying four snow tires.
I don't know why the cable chains I bought say they fit my size tire but don't. I'm going to return them, and order a pair made by SCC, the manufacturer Subaru sells in their parts dept.
Just FYI. Thanks again!