A fierce bushfire swept through Koolewong on New South Wales Central Coast over the weekend, destroying 16 homes. High temperatures and strong winds helped the fire jump a 1km-wide water stretch on Saturday afternoon. Police confirmed active crime scenes at houses on Nimbin Avenue, Glenrock Parade, and John Street. The Arson Squad and forensic officers are investigating the cause, but the Rural Fire Services (RFS) commissioner, Trent Curtin, said, "We don’t want to speculate at this stage as to what the cause might be. There are many things that it may be." An officer was seen carrying a plastic evidence bag with a red jerry can at the scene. Investigations were temporarily stopped due to safety concerns, with structural engineers called in. Police stated, "Investigations are anticipated to recommence once the area has been declared safe by authorities." Fire teams from NSW Police, Fire and Rescue, and the RFS will keep working in the area for the near future. Elsewhere, four homes burned at Bulahdelah on the mid-north coast, and in Tasmania, 19 homes were lost in Dolphin Sands. The Tasmania Fire Service issued a "watch and act" alert, urging residents to stay alert though no immediate danger exists. Dolphin Sands Road reopened Tuesday afternoon after closure since Thursday's blaze. Firefighters continue to battle a large bushfire south of Bulahdelah, burning 4,600 hectares in Myall Lakes National Park. Back-burning efforts helped contain the fire. Residents like Tracy from Nerong stayed vigilant, with local fire crews on full alert protecting homes. With hot, dry weather expected, the RFS warns communities near Bombah Point Road, Crawford River, and the Branch to monitor fire conditions closely. Smoke from the fires worsened air quality from the Central Coast to Sydney. Measurements showed poor air quality in Lower Hunter, Lake Macquarie, and Central Coast regions Tuesday morning, with fair levels in parts of Sydney.