.... Would "lari blanch" indicate a path covered in snow?

Maybe. It depends on the context.

Lari a tou blanch.
The street is deserted.

Lari tou blan ak lanèj
The street is covered in snow.

One of the meaning of 'blanch' in Haitian Creole is vacancy, lack of (something) or desertedness:

Bay teren an blanch.
Bay kay la blanch
to leave

pase yon nuit blanch
to have a sleepless night


Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words