I built a snowmam about an hour ago, was able to talk to it and hung around the area for 10min or so. I talked to Snowtyke and he said he wished his brother and papa were there with him in the same town (implying at this time he knew about his mother being there). I puttered around for a bit in my town, fishing and visiting the museum and nook's store. I came back about an hour later to check in on my unfinished snow-family and saw that my Snowmam was gone! I talked to Tyke and he asked me to build all of his family members for him, including Snowmam. Is this a bug or have I done something incorrectly? Does anyone know how I can get her back? There aren't anymore snowballs on my island for today.
Yeah this happens to me too sometimes, usually if I build her too close to an object or other snowperson. The odd thing is that the game still thinks she's there, because snowflakes will spawn even when it's not snowing, and yet oddly enough Snowtyke will still request her to be built. The only thing I can recommend is giving her plenty of space if you didn't the first time, I don't think I've ever seen her disappear out in the open but I could be wrong.
Snow people disappear when they're too close to trees, bushes, rocks, buildings, etc. Make sure there is one space all around it when you build it! Also, if you build it too close to another snow person, it will just move one space over (in my experience!)
I love building the snowmen, women & kids. I've built them too close to each other, and they've been pushed back (or over, or whatever), but they've had room to get moved over, so they've never completely disappeared. Glad I know this now!