The February 9–11, 2017 North American blizzard was a fast-moving but powerful blizzard that affected the Northeastern United States with winter weather in the time span of February 8–9. Forming as an Alberta clipper in the northern United States, the system initially produced light snowfall from the Midwest to the Ohio Valley as it tracked southeastwards. It eventually reached the East Coast of the United States and began to rapidly grow into a powerful nor'easter. Up to of snow as well as blizzard conditions were recorded in some of the hardest hit areas before the system moved away from the coastline early on February 10. Prior to the blizzard, unprecedented and record-breaking warmth had enveloped the region, with record highs of above recorded in several areas, including Central Park in New York City. Some were caught off guard by the warmth and had little time to prepare for the snowstorm, with some meteorologists calling the extreme weather changes "unprecedented". Meteorological history On February 6, an Alberta clipper developed near the Canada–United States border and dove southeastwards. With relatively little moisture to supply it, initial snowfall totals in the Plains and Midwest were light, ranging from . The system quickly advanced eastwards through the heart of the country, and by 18:00 UTC on February 8, a surface low had developed over the Arkansas–Tennessee state border. This low would become the dominant low of the system as it continued towards the Northeastern United States, while also producing light to moderate snow across the Ohio Valley since there was enough cold air in place from a departing storm system. As the clipper system neared the tri-state area, it began to steadily intensify and produce more moderate and heavy snow while beginning to make the transition into a nor'easter. By 09–12:00 UTC on February 9, the low had begun to move just offshore near the Delaware coastline. As very heavy snow bands (with snowfall rates of in some spots) set up offshore, forecasters noted that the low was likely to rapidly deepen – or in meteorological terms, bomb out – due to the temperature contrast between the cold air to its north and moisture feeding into the storm from the warm waters of the Gulf Stream. Indeed, the storm had undergone this process, meeting the criteria for bombogenesis, with the central pressure dropping from at 18:00 UTC on February 8 to by 18:00 UTC