As far as I can tell there is no information available on the web
Post on the Trip Advisor Slovenia board - there are locals who respond to posts there daily and would know for sure.
Yes, it's open, but currently only for passenger cars, it's closed for vans and motorhomes. You can keep track of traffic conditions on Slovenian roads on the official website of the Traffic Information Center: http://www.promet.si/portal/en/1traffic-conditions.aspx
When I asked at the local ti, they said I needed winter tires to try the pass. So we wound up detouring through Italy. One of the best parts of that drive was seeing the rusted, abandoned border checkpoints.