In this post-apocalyptic short story, a small group of people are returning from a (failed) effort to save one outpost.
They cross a snowy wasteland to find that the nearest domed refuge has also ceased functioning and are forced to stretch their supplies and physical resources to reach a farther afield one.
The story ends with them barely reaching their goal to find a warm and civilized society inside the refuge. I believe hot cocoa features in the final scene.