Magic realism is a form of narrative that treats the supernatural, mythological, and magical no different from its realistic aspects. In Garcia Marquez's fiction, he adds the element of emotions manifesting as real events. For example, it seems that it rains whenever people are sad or mourning, anger literally twists a person's features into something grotesque and turns them into a living ghoul, and so on.
In the "Chronicle of a Death Foretold," there are many such elements to be found. A lot of these have to do with the Vicario twins, who all throughout the book are described as trying to prevent the murder they themselves commit. It's unclear whether it's due to pacifism, not really believing their sister, or just resenting their traditional duty. Magical realism is particularly strong around them. When they murder Santiago Nasar, a blade remains clean and spotless even after being stabbed through a person's body three times. Later, in their holding cell, they can't get rid of their victim's scent, no matter how hard they try or wash themselves and their clothes. Clearly the scent lingers due to their guilt, but the author does not make that distinction. It's up to the reader to treat these elements of the supernatural either as artistic liberty or actual truth. It's the possibility of this dual interpretation that places the work in the genre of magic realism.
The genre helps bridge the gap between Realism and the possibly supernatural world of Latin America. It's important to realize that what magic realism attempts to do is to give the reader the feel, rather than actual facts, of what it's like to live in a society strongly ruled by superstition and traditions with long-forgotten roots and old wives' tales. It's also the realm of ancient wisdom the new world has forgotten and a place where people are so strong that they warp their surroundings through sheer force of their personalities. These are realistic things that can seem magical, once we've lost the ability to comprehend them. Magic realism blurs the distinction completely.
The tale of "Chronicle of a Death Foretold," like all Garcia Marquez's works, is an eerie tale where omens could very well be gut feelings and vice versa. One element of magic realism is the overbearing sense of coincidence in the book. So many things had to go wrong, on every plane of existence, for Santiago Nasar to die the way he did. His mother, usually good at interpreting dreams, sleepily misses the warning signs. Every person in the community develops roughly the same case of "it will never happen". People trying to save Santiago miss him by seconds, and the victim manages to walk into a trap so easily that the author simply determines that if fate truly wills us dead, we might as well be invisible.
Magic realism involves the interweaving of magical or supernatural events into a realistic narrative to provide greater emotional depth to the characters and the readers' response to the narrative. Chronicle of a Death Foretold has, in parts, a journalistic approach to retelling the narrative; however, there are elements of magic realism throughout the narrative. For example, Santiago Nasar's dream on the day he dies is an element of magic realism. The author describes it in the following way:
He'd dreamed he was going through a grove of timber trees where a gentle drizzle was falling, and for an instant he was happy in his dream, but when he awoke he felt completely spattered with bird shit.
These strange, almost magically symbolic elements add a dimension of magic realism, as the dream contains an omen that Santiago Nasar doesn't recognize at the time but that foreshadows his death.
The way in which Bayardo Sam Ramon arrives in town also has supernatural elements to it. He is described in the following way:
He was around thirty years old, but they were well-concealed, because he had the waist of a novice bullfighter, golden eyes, and a skin slowly roasted by saltpeter.
Magdalena Oliver describes Bayardo as looking like a "fairy," conveying that Bayardo has a supernatural quality to him. These elements of magic in the midst of retelling the story of the murder elevate the emotionality of the story. In addition, the existence of the factual narrative alongside the magic elements convey to the reader the idea that there are two sides of reality—one realistic and the other magical—deepening the reader's experience of the novel.
Magical realism as a genre is often associated with Latin litterateurs who, like Gabriel Garcia Marquez, make good use of the richness of their native tongue to produce powerful parables, and situations of a dissociative nature which allow the reader to create a metaphor or allegory on their own accord.
An example of magical realism in Chronicle of a Death Foretold is the importance placed on symbols and premonitory dreams as factual pieces of information. The fact that these symbols help to guide the plot of the story lead us to understand the important role which they play within it. Also, the disguising of the brothel when it is described as a form of magical place whose scent and strange elegance invites the reader to wonder what kind of place it actually is happens to be an instance of magical realism. It is as if something surreal was in the atmosphere taking the place of what is actually there.
These forms of allegory are similarly exposed in One Hundred Years of Solitudewhere we encounter the character of Pilar Ternera, for example, whose specific "scent of smoke" seemed to hypnotize her lovers and rendered them weak in her presence.
Therefore, you could argue that magical realism is, in a way, a form of existential literature with less depth but more allegorical content, and Marquez is the absolute conqueror of this type of genre.