Yeah from the looks of the wreckage my guess would be icing, stall, flat spin. Add disorientation in IFR conditions once the spin started.

Really a sad situation .

Crews are trying to recover the aircraft or as much as they can. Weather and moving ice is preventing that so far. Interesting aspect is deicing. Pretty sure that aircraft had the TKS system. It oozes an anti ice fluid to PREVENT icing. Different than the rubber boots that remove icing. The fluid is also used to keep the prop clean. The caravan also has a good auto pilot.
Pressurized aircraft can usually climb out of icing conditions. Caravans aren't pressurized.

I was wondering how fast the fuselage was building ice while fuel weight was burning off............moving the CG aft and inducing the stall.