You'll notice that everyone kind of just accepts that there is an angel. The other characters are shocked, but do not doubt the authenticity of the angel (except for the local priest who asked for confirmation from the Pope). Also in this story, Marquez mentions a woman who turned into a spider and recounts the tale to a paying audience, another example of magical realism.
From nearly the start of 100 Years of Solitude Marquez makes it clear that this book has a large amount of magical realism. After José Arcadio Buendia kills Prudencio Aguilar, Prudencio's ghost comes back. The characters just accept this. The book has many examples of magical realism. Some of my favorite examples include Remedios the Beauty floating up to heaven on bed sheets, an old lady (representing Death) predicting Amaranta's death directly after her complement of the shroud, and Melquíades's ability to predict 100 years worth of history. The characters accept all of this. In fact, when Remedios was floating to heaven, Úrsula didn't even find that impressive because she had already seen magic flying carpets. By exaggerating events, Marquez makes them fantastical, but by being very specific he gives these events a sense of reality.
Latin American culture is very superstitious, so including magical realism in this society makes sense. Below is an article if you want to read some Latin American superstitions. This article reminded me of Pilar Ternera and Úrsula as well. These are some things that they might try to tell others about. I could see Marquez including these superstitions in the magical reality of 100 Years of Solitude.