A powerful winter storm swept across the US, leaving at least seven people dead and causing power outages for more than 800,000 homes. Dangerous ice, heavy snow, and freezing rain spread from Texas to New England. Schools and roads shut down, and over 11,000 flights were cancelled. The National Weather Service calls the situation "life threatening." Two men died from hypothermia in Louisiana. Texas officials reported an "exposure-related" death in Austin. Kansas police found a woman's body covered in snow, likely due to hypothermia. Tennessee reported three weather-linked deaths. New York City Mayor Zohran Mamdani said at least five people died in the city over the weekend, but causes are still under investigation. Governor Kathy Hochul of New York warned, "This is certainly the coldest weather we've seen, the coldest winter storm we've seen in years. A sort of an arctic siege has taken over our state and many other states across the nation." Kentucky Governor Andy Beshear said the state is seeing heavier ice than snow, which threatens trees and power lines. Virginia and Kentucky have faced hundreds of crashes due to icy roads. Nearly half the US states have declared emergencies. Washington DC is experiencing its biggest snowstorm in a decade, said Mayor Muriel Bowser. Schools canceled classes and the US Senate delayed its Monday vote. The storm stems from a shift in the polar vortex, a ring of strong Arctic winds that brings very cold air south when weakened. The cold weather is expected to last into early February. Experts suggest climate change might affect the polar vortex's behavior by altering sea surface temperatures. Canada's Ontario also faces heavy snow of 15-30 cm and many flight cancellations. This storm affects roughly 180 million Americans, more than half the US population.