The amount of winterkill tends to depend upon the previous year’s dry conditions. Things like how fast the snow melts, how many times the meltwater under the snow on your lawn freezes and thaws, whether the lawn faces north or south — all of these factors will affect the prevalence and severity of winterkill.
But the most common cause is meltwater that gets trapped on the lawn that has gone through several hard freezes and thaws. So each time the lawn refreezes, the grass plants suffer microfractures, particularly in the roots, as the soil expands, contracts, and heaves.
Too much of this root damage inevitably leaves the plant without a source of food. It appears green at first in the spring, but quickly dies.
Regrettably, there is no way to bring it back. The affected areas should be raked thoroughly to remove dead material and thatch. Lay down a light layer of topsoil and rake in a generous amount of seed.