“Willis seems to be directed against claims that are not made in the paper as the paper refers always to regional changes in snowfall”
I actually I noted that myself and I have asked Willis to clarify in comments there. The paper actually talks about total snowfall, not extent and it does point out that it is autumn sea ice extent that is the important factor, whereas Willis has looked at total annual sea ice area and snow extent as opposed to total fall.
I also did notice that the body of the article included uncertainty that and appropriate equivocations, but the abstract does not.