Forecasters say parts of Alabama could have more than a foot of snow on the ground by the time the wintry precipitation ends.
A winter storm warning covers nearly the entire northern half of the state, and many schools and businesses are closed or opening late on Wednesday.
The National Weather Service says snow and ice totals ranged from just a trace north of Birmingham to 6 inches in Alabama's northeastern corner on Tuesday.
The weather service says the areas that got the most snow could receive another 8 inches by Thursday. And Birmingham and Huntsville could both be coated with snow and ice before the precipitation ends, hampering travel in metropolitan centers.
The governor has issued a state of emergency, and authorities are asking drivers to stay off roads.