Refers to the melting of frost or frozen ground, often in early spring. Can be used literally or figuratively for a softening or relaxation of a cold situation.
As spring approached, the thawing road was muddy.
When the thawing season comes, farm work begins.
Compound of 霜 (しも, 'frost') and 解け (どけ, the noun form of 解ける 'to melt, to thaw'). The reading どけ is a rendaku form of とけ.