australian scientists launch a campaign to find it. forecasters in the us say a major winter storm sweeping the us this week may bring the coldest christmas in four decades to parts of the country. there has already been major snowfall in many areas. more than 90 million people in 37 states are set to experience sub zero temperatures, including places as far south as texas. tom brada reports. a fierce winter storm is sweeping across the united states. more than 100 million people are under winter weather alerts, with warnings of ice, snow and freezing winds. at a white house briefing, president biden called for caution. this is really a very serious weather alert here, and it goes from oklahoma all the way to wyoming and maine. it s not like a snow day when you re a kid, this is serious stuff. meteorologists say the winter storm could become a bomb cyclone an unofficial term for a certain type of powerful storm, which rapidly builds in strength. heavy snowfall and strong wi