This index, from NOAA's National Weather Service, attempts to scale the impacts from winter weather, taking into account factors such as snowfall, accumulated snow on rooftops, ice accumulation, the potential for a flash freeze, and blowing snow. Not all factors are in play in a given winter storm.

We have two relatively new types in winter weather warnings, called extreme cold warnings and cold weather advisories. Let's look at what those mean, and where they are in effect this weekend.

The major storm is set to hit starting on Jan. 23 and will stretch into the weekend, spreading snow and ice from the southern Plains to the Northeast.

The National Weather Service issues a litany of notices before and during inclement weather events. They can be important signals on how to respond.

Severe winter weather warnings have fueled extreme price hikes in the notoriously-volatile natural gas market.

As a winter storm approaches Western North Carolina and other regions, here's what to know about deciphering forecaster terms.