Central Queensland is about to, er, "receive" one of the biggest cyclones in living memory - Cyclone Yasi. It probably won't affect much us in Brisbane. However, being a flood engineer, I have collected some facts and figures. Also, being a pom, I have a genetic predisposition to talk about the weather...
The last cyclone like Yasi was probably Mahina, which occurred in 1899.
Yasi is so big, that if it hit America, it would cover the entire eastern seaboard from Newfoundland to Florida. If it hit the British Isles it would cover it from John O'Groats to Marseille.
Yasi is Category 5. It's a measure of severity There is no Category 6.
Yasi is expected to produce wind gusts of up to 280 to 300 km/hr, which equates to about 75 to 80 m/s. The eye has been travelling at about 30 km/hr, or 8 m/s. In a sprint, the fastest humans can run at about 10 m/s, and the speed of sound is about 330 m/s. So, you could hear it coming, but you won't be able to outrun it.
Yasi is expected to produce a storm surge of 6.5 to 7.0 m. That's the elevation of the sea above astronomical tide level (due to inverse barometric pressure). If it crosses the coast at about 3:00am tomorrow morning, it will coincide with a low tide, but if it waits until about 9:30 it will hit a high tide, which is about 2.5 m above mean sea level, resulting in sea levels about 9 to 10 m above mean sea level. Rule of thumb: if you're buying property in North Queensland, make sure it is at least 10 m above mean sea level. (Some residences in Brisbane are as low as about 3.5 m above mean sea level, but cyclones are much less frequent here).
Yasi is expected to dump up to about 1 m of rain as it passes in the next day or so. By comparison, the mean annual rainfall in Brisbane is about 0.9 m, and in the UK it's about 0.8 m.
All 250 patients in the Cairns hospital have been successfully evacuated to Brisbane.
About 20,700 people have taken refuge in Temporary Cyclone Shelters. The Shelters are now full, and Police are turning away latecomers.
At about 4:00pm, State Premier Anna Bligh announced that if you hadn't evacuated yet, you shouldn't try. Your best bet would be to hunker down in the strongest room in your house, which is usually the bathroom. Fancy spending the next 24 hours in your toilet? With no power? With all your family present?