Complex sentence: In August 1955, severe flooding on the Blackstone caused extensive damage to Woonsocket, Rhode Island; where the river is usually 70 feet (21 m) wide it swelled to over 1 mile (1.6 km) wide.
Split into simpler sentences: In August 1955, severe flooding on the Blackstone caused extensive damage to Woonsocket, Rhode Island. Where the river is usually 70 feet (21 m) wide it swelled to over 1 mile (1.6 km) wide.