Tropical Cyclone Debbie is making landfall across the coast of northeast Australia, packing sustained winds of 185 kph (114 mph) with gusts reaching more than 262 kph (163 mph).
The storm is lashing the Queensland coast with torrential rain, bringing about a significant flooding risk, meteorologists said.
The Category 4 cyclone is the equivalent of a Category 3 hurricane and is very slow-moving.
"With the very, very strong winds if they just sit there and twirl, it's like a battering ram," Queensland police commissioner Ian Stewart told CNN affiliate 7 News.
It's already left a path of destruction through outlying islands.
"Scariest thing I've ever gone through," Sassha Kozachenko said on Instagram. On Airlie Beach, detritus and debris could be seen hurtling through the air in videos posted on social media.
The storm already has ripped trees from the ground and brought significant rainfall to the region.
Residents reported their apartments shaking and windows breaking. Pristine beaches that were bright and sunny Monday were completely flooded Tuesday.
In the span of an hour, 211 millimeters (8 inches) of rain hit the area, Queensland Premier Annastacia Palaszczuk said. It was a once-in-a-hundred year event, she said.