Voles damage lawns

As the snow melts (eventually), you may find surface tunnels on your lawn caused by voles.  This can be a disturbing image and is most unpleasant.  Voles, also known as field mice will tunnel under the snow, eating the grass and shallow roots of your lawn.  The result of this frozen dinner feast is a maze of tunnels created where the mice traveled.  The extent of the damage can be minor such as leaves and thatch being eaten all the way to roots and shoots a more severe result of mouse lawn damage.
Your best bet is to let the area recover in April and do some seeding in May once the soil warms up enough. Depending upon the extent and depth of the damage, you may not have to do anything, the lawn will recover once it begins to grow as the weather warms.  Prevention is your best bet.
In the fall, make sure you cut the lawn short down to 1.75″ if possible to reduce the food source for vole damage. Placing moth balls around perennials or herbaceous shrubs can also help deter vole activity.  As plant eaters, voles will seek out a food source, especially under the comfort and safety of snow.