According to Paolo, the changes can be explained by El Niño forcing a high pressure anomaly into the low - pressure system parked over the Amundsen sea, impacting wind patterns and driving more snowfall in West Antarctica. (earther.com)
In fact, the jet stream swung north to latitudes never before observed at that time of year; the winds during July reversed their normal pattern, and southern Greenland — where melting has been at record levels for most of the decade — actually saw more snowfall and lower melting in 2015. (climatenewsnetwork.net)
It needs to be clarified here, that it is hypothetically possible to get more snowfall and snowpack in a globally warming world (at least for a while), due to increased precipitation (which is predicted in a warming world, esp for the higher latitudes) coming down as snow. (realclimate.org)