Complex sentence: Steadily strengthening as it tracked south-southwestward, the storm intensified into a hurricane on September 23, and after turning to the southwest it reached a peak intensity of 105 mph (155 km/h) on September 24.
Split into simpler sentences: Steadily strengthening as it tracked south-southwestward, the storm intensified into a hurricane on September 23. After turning to the southwest, it reached a peak intensity of 105 mph (155 km/h) on September 24.