The National Weather Service (NWS) has issued frost advisories and freeze warnings across 12 states as colder weather arrives with the fall season. Many states have already seen their first frost, and cold temperatures are spreading as the season progresses.

Spring is traditionally the most dangerous time of year when it comes to destructive tornadoes and other severe weather outbreaks in much of the southern and central United States. But autumn brings a “second season” of sorts, often with a bump in tornado counts during late October and November.