25-30 years ago, I saw a farmer sowing clover seed on top of 3"- 4" of snow. I thought it was crazy, but after telling a few guy that farmed said they used to do it all the time. Supposedly the melting snow would take it right in the soil.
Years later after finding out about the frost seeding method, I thought maybe it did take the seed to the soil surface, then later during the freeze/thaw cycles, it may take it on in. Thinking maybe they were just getting ahead of the game.
Here, if inter-seeding in already established hay field I have ran the disk over it a couple times just to open the surface a bit to get soil contact in late Fall, getting ready for early Spring freeze/thaw cycles. Surface mellows after the Spring freeze cycles. I normally don't see the full potential of what I sowed until the second year after sowing.