What's going on here?

Here's an event that occurred around 1965, but what is it? That's the late Margaret Linser with Betsy Thomas, Sara Smith, Lynn Dietz, Marilyn Olson and Betty Larson. (Is that Paula Widstrom in the background?) Why are these people standing in the snow and what's with the red and white flags? Where are all the boys? Where is this? Sara, who supplied the photo, says: "I have no clue when or where this was taken." Betty Larson, contacted by phone in Arkansas yesterday, could only speculate. She remembers that Betsy's mom used to throw a birthday party in February at their Lake Carlos home. Could this be a birthday party? Does anyone recognize the building? Are those really kickerinos?