Mole mounds are cylindrical in shape vs. the crescent/horseshoe shape of a gopher mound. In sandy loam soils, mole mounds are chunky while gopher mounds are fluffy.

If allowed, probe between the mounds and see if you can find mole tunnels. Or, when you guys thaw out, look for surface/foraging tunnels (raised ridges) in and around these mounds. If so, you've got moles!