Significant snowfall is expected to disrupt highways across the South Island by Wednesday, according to weather forecasts. The region is facing a sharp temperature drop following a cold front, with conditions worsening through Thursday. Christchurch is set to experience a warm start to the week before the weather turns sharply colder. Local authorities are preparing for potential road closures as snow accumulates in higher elevations. Travelers are advised to monitor updates and plan accordingly for possible disruptions. The situation highlights the seasonal challenges faced by the region during winter months.