A powerful winter storm sweeping across the U.S. has caused more than a dozen deaths, widespread power outages and extensive flight cancellations. The storm left many without electricity, particularly in southern states, and grounded flights at major airports, including a significant number at New York's LaGuardia Airport. Affecting more than half of the U.S. population, it is expected to continue disrupting daily life and travel through the week due to persistent cold and ice accumulation.