After the snow has melted, the lawn can be raked to clear off debris accumulated during the winter. This should be done quickly because as little traffic as possible should be on the saturated lawn at this time.  Thatch shows up as a light brown layer of decaying vegetation, mostly old leaf sheaths and root growth from previous years. The average 7,000sq ft size yard can produce over 1500lbs of residue after Dethatching.