Heavy Leaf pack will smother, stress and kill newly germinated grass seed that was planted this fall.  Please make sure to keep leaves removed from the turf to avoid damage.  Also, we're still very much in a drought…most everyone has had their sprinkler systems blown out for the winter so you MUST water manually, especially new grass.  If the plant is forced to go into domancy drought starved, it will die and not come back in the spring.