The tropical storm, named Alfred, is on track to bring dangerous winds and flooding along the coast of southeastern Queensland, including the country’s third-largest city.

Cyclone Alfred is unusual for two reasons — it has formed way too south, and is moving slowly. Both these factors make it more dangerous. We explain why.

Residents are stacking sandbags to protect low-lying properties ahead of a tropical cyclone that is forecast to become the first in 51 years to hit the Australian east coast near Brisbane, the nation’s third-most populous city.