The Bureau of Meteorology has issued a severe weather warning, forecasting damaging winds and heavy rainfall across much of the state.
The warning is for people in the Adelaide Metropolitan, Mount Lofty Ranges, Lower Eyre Peninsula, Eastern Eyre Peninsula, Yorke Peninsula, Mid North, Kangaroo Island, Murraylands, Upper South East, Lower South East and parts of West Coast and Riverland districts.
Locations which may be affected include Port Lincoln, Whyalla, Clare, Maitland, Adelaide, Kingscote, Murray Bridge, Naracoorte and Mount Gambier.
Sheep graziers are warned rainfall overnight tonight into Thursday will be followed by further showers, colder temperatures and fresh to strong westerly winds from about midday Thursday through to Friday afternoon.
There is a risk of losses of lambs and sheep exposed to these conditions.
The State Emergency Service advises that people should move vehicles under cover or away from trees, secure or put away loose items, don't drive, ride or walk through flood water, keep clear of creeks and storm drains and stay indoors, away from windows, while conditions are severe.