The London Beer Flood, nicknamed the Beer Tsunami by the Eleventh Doctor, was a disaster which occurred on 17 October 1814. A vat containing over 135,000 gallons of beer burst in the Meux and Company Brewery on Tottenham Court Road, causing a domino effect. Other vats in the brewery collapsed and over 323,000 gallons flooded the nearby streets destroying two homes, pub, and killing eight people.
After sending the Eleventh Doctor and Rory Williams on a "boys night out", Amy Pond, while looking for something to entertain herself, saw an agent of the Silence and followed him to the brewery. After witnessing the flood, Amy confronted the agent and he explained that the London Beer Flood was a fixed point in time and that it was his job to ensure it occurred. Amy then searched the flood on her phone and read that fifteen people had died. A cry for help led her to a mother and two children who were supposed to have been killed yet, presumably due to Amy's presence, had survived. Amy figured that this meant that only the flood itself was a fixed point and that the death toll could be rewritten. She then set off to save as many people on the list as she could, presumably bringing it down to the eight who are officially listed. (COMIC: The Doctor and the Nurse)