I'm looking for a recent (last four years?) SF story about a family enjoying a nice day in their house at Christmastime, watching the snow fall in the forest near their home through the windows. The children ask the parents about visiting the grandparents and getting to play in the snow.
the father brushes off the childrens' requests. The mother tells him in private that he should tell the kids what's really going on. We discover the truth when the power goes out, and we find that the windows are actually TV screens playing a winter scene. A gang of scavengers break in, and steal the family's batteries, food and water. The father pleads that the family can share what they have, to which the lead scavenger replies, "you should have been better at sharing when you had a chance". The family goes outside to watch the departing scavengers, where it's revealed that it's oppressively hot, and the forests have been destroyed by fire. It's either stated or implied that the grandparents haven't been heard from for months and are probably dead. One of the children comments that the snow on the ground is warm, and the wrong color. The mother explains to the child that it's not snow, but ash.