"Grolar" and"Pizzly" bears (Grizzly/Polar bear hybrids) are in the news again, since an Inuit hunter in Nunavut thinks he has recently shot one (Edmonton, Alberta, "Metro", 24.v.2016, p. 10).
Forcuriosity, are hybrids of Grizzlies and (American) Black Bears known? (At aguess, they would be less likely, since (i) the species are not as closely related and (ii) there is I think a significant size difference.)
Free associating... are American Grizzly Bears and European Brown Bears still thought of as conspecific, or has the newer trend of splitting mammals (which has, for example, once again separated Cervuselaphus fromCervus canadensis)
affected them?

There is actually a wiki page on bear hybrids that may be of interest.

https://en.wikipedia.org/wiki/Ursid_hybrid

Bottom line is hybrids can be possible but offspring are typically sterile. Black bear/grizzly hybridisation has happened in captivity. It has also been reported in the wild but - to me knowledge - all claims have been based on morphology and I'm not aware of any good DNA evidence (which is what is really needed to meet the standard of evidence these days). Grizzly/polar bear matings are indeed thought to be more common (with DNA evidence to back this up) and  - possibly on the rise as per the story circulating today that you highlight - some links here:

http://www.independent.co.uk/environmen … 46611.html

https://www.washingtonpost.com/news/ani … ow-mating/


"Grizzly" bears are North American subspecies of  Ursus arctos (brown bear) . In fact there are several subspecies recognised in N. America but all may be referred to as grizzlies. There is a long and complex history of subspecies designations for U. arctos, see https://en.wikipedia.org/wiki/Brown_bear , but bottom line is that they are all presently designated as one species, and most biologists would say that "supspecies" designations are pretty arbitrary/pointless in terms of biology (though they can be useful for conseravtion and management purposes).