Chicago, IL – SNOW! As early winter systems begin to develop in November and move across the Great Lakes, meteorologists are urging residents to understand the difference between a Winter Storm Advisory and a Winter Storm Warning — especially before heading out on I-90, I-94, or near the Lake Michigan shoreline.
According to the National Weather Service (NWS), a Winter Storm Warning means hazardous winter weather — such as heavy snow, sleet, or ice — is expected or occurring. Conditions could make travel dangerous and may cause visibility to drop below a quarter mile for several hours. Warnings are typically issued when confidence is high that a storm will have a major impact.
A Winter Weather Advisory, however, signals that lighter snow or ice is expected but could still cause slick roads and delays. While not as severe as a warning, advisories can still lead to accidents if drivers underestimate conditions or fail to reduce speed.
The NWS says alerts are based on local thresholds, meaning what triggers a warning in northern Wisconsin may only be an advisory in southern Illinois. Lake-effect snow bands can also intensify quickly near Lake Michigan, creating sudden whiteouts even when only an advisory is in place.
Drivers are encouraged to keep emergency kits in their vehicles, check weather.gov for updates, and avoid travel during active warnings whenever possible.
