This map by Redclaw is a winter-ized version of the Half-Life 2 map DM_Runoff.
It has been laid out with snow textures and some trees have been given Christmas lights. There are also soda machines that dispense SLAMs, seeing as this was originally made as a Half-Life 2 Deathmatch map. But it's also nice for screenshots and comics.
Download it here:
And if you want more information on this map, or need some help or support for it, check out the forum thread.[...]