This short story from the collection Wild Child was originally published in the New Yorker.

Gordon is a delivery driver with a predilection toward road rage, and he's on the most important delivery of his life. In Santa Barbara there's a mother of three on life support waiting for Gordon, waiting for the liver he's transporting from Los Angeles. But there's a mudslide, and cars are being swept away, people being buried in the sludge. And Gordon, who's as far from a hero as they come, has to find a way to get the liver to Santa Barbara.