Winter storm warnings are in place for 10 states from the National Weather Service (NWS) on Thursday, with up to 30 inches of snowfall expected in some parts of the U.S. Freezing temperatures may present health risks, especially for vulnerable groups such as infants and older adults.

During the winter months, the National Weather Service often issues warnings, watches and advisories ahead of weather-related events like snowstorms. Here's what they mean.

Storm Watch was expanded this morning to include all of Southeast Michigan starting Wednesday afternoon through Thursday morning. This watch precedes advisories and warning.