If you live in a place where it snows, you probably know the drill. Forecasters will predict a massive snowstorm. Grocery stores are emptied. And then there's just a light dusting. It happens every winter, in part because we don't really understand how these storms work. But a new study from NASA hopes to change that. The IMPACTS mission wants to improve our understanding of snowstorms and, in particular, of what are known as snow bands. Here to talk about the program is Lynn McMurdie, principal investigator on IMPACTS. Welcome. LYNN MCMURDIE: Thank you. Happy to be here. CHANG: So what exactly are snow bands? I have never heard this phrase before. MCMURDIE: OK. Well, within a snowstorm, which you have heard about, the clouds associated with them span a large area. They can be, you know, as far as Florida up to Maine. But within those clouds, you have narrow regions where the snowfall is far more intense, and they often are organized in kind of a narrow band. And we could just call those snow bands.