This small mammal could be confused at first glance for mouse or vole, but instead it's a shrew..
I think it was probably a Water Shrew (Sorex palustris). There are several species of shrews that can be found in Michigan's Lower Peninsula: the Masked Shrew (S. cinereus), Pygmy Shrew (S. hoyi), Water Shrew (S. palustris), Least Shrew (Cryptotis parva), and Northern Short--tailed Shrew (Blarina brevicauda).
Three of the species can be eliminated right away. The Pygmy Shrew, Least Shrew, and Short-tailed Shrew could all be eliminated by overall size or tail length.
The Masked Shrew could be eliminated by fur color and the amount of fur on its tail. The Masked Shrew has light brown fur and a lightly furred tail - this animal was almost black and had a moderately furred tail.
Therefore, my best guess at identification is that this animal is a Water Shrew.
During the winter it is unusual to find a shrew on the surface of the snowpack. Normally they would be found traveling through the subnivean zone where they are hidden from avian predators. This shrew seemed to be searching for a way back beneath the snow.