The effects of the polar vortex in the United States were initially felt in the Midwest, but these low temperatures quickly spread to nearly all portions of the Eastern and Texas Interconnections. Temperatures were far colder than those normally experienced in winter, resulting in record winter peak electric demands with increased electric heating requirements. This is the first time that data from the NERC Generation Availability Data Systems (GADS) was used to analyze generator availability during an event such as the polar vortex.