Residue can be removed by grazing or burning in the spring but either may delay seeding. I do not recommend frost seeding on top of snow because rapid snow melting may cause the seed to be washed off the pasture. Frost seeding should be done in March. Earlier seeding will also result in seed loss by birds, rodents, etc. Frost seeding works best for legumes and grasses that germinate rapidly.
Red clover is the easiest to establish.