The storm is forecast to bring as much as 8 inches of snow to some areas of the state and up to an inch of ice in other areas.
The state of emergency took effect at noon Tuesday and put the National Guard on active duty to support state agencies. The guard has wrecker teams and four-wheel drive vehicles that can be used in the storm response.
The order also puts into effect anti-price gouging laws and allows the governor to take whatever other steps are needed to protect residents.
Haley issued a second executive order waiving weight limitations for trucks transporting emergency materials, equipment and supplies.