Image © Roger Hayden - all rights reserved
Government data show that bear deaths during 2015 shattered previous records, and that thresholds for allowable female deaths were exceeded by a large margin (link). The death toll of 85 grizzlies is not an anomaly, but rather the most recent manifestation of a decade of unsustainable high grizzly bear mortality.
According to the federal government, a total of 58 known and probable grizzly bear deaths occurred in 2016, which nearly surpassed the jaw-dropping record set during 2015. Further, these "known" and "probable" mortalities are not the whole story, simply because many bear deaths go unrecorded. When you apply an estimator that the federal government uses to account for this unknown mortality, about 75 bears or 11% of the Yellowstone grizzly bear population died during 2016.
According to the federal government, a total of 50 known and probable grizzly bear deaths have occurred so far during 2017, the most recent dating back to November 2nd. Of these, all but 3 occurred inside the Demographic Monitoring Area (DMA). Given the lag in time between when deaths occur and when they are posted online, we can expect this total to increase before the last bears are in their dens.
Grizzly bear mortalities have increased dramatically since roughly 2000, far in excess of anything that can be explained by changes in population size. The most important trend is the substantial increase in mortality that followed hard on the heels of when we lost most whitebark pine in the ecosystem.