Due to the unprecedented amount of snow over the winter you may see slimy gray patches on your lawn. While it is caused by a fungus, it is commonly known as “snow mold”. 
It can be treated with fungicide but this is largely unnecessary and since most fungicides are short lasting if the temperatures don’t exceed approximately 68°F the symptoms will most likely reoccur. Common practice is to rake the area to remove most of the diseased tissue and fluff up the lawn to allow the affected plants to dry.
One treatment that I do not recommend is quick release, high nitrogen fertilizer that can be used to “grow out” the trouble spots but can also contribute to succulent growth which causes the lawn to be more susceptible to not only the snow mold we are seeing now but also other lawn diseases.