A third wave of sleet and drizzle could hit parts of the central U.S. on the eve of the holiday, and temperatures threaten to stay near or below freezing and add to the treacherous mix.

Ice buildups of one-quarter to slightly less than a half inch were expected late Saturday and Sunday morning from southeastern Kansas to central Missouri.

Becky Allmeroth, a state maintenance engineer for the Missouri Department of Transportation, says ice is “the most difficult storm to fight.” Her department has been scrambling around the clock to treat the glazed roads.

Icy roads Saturday created dangerous conditions and travel headaches for many people who avoided authorities’ pleas to stay indoors. The storm followed one Friday that dumped freezing rain from Oklahoma to southern Illinois.