Yasi: Big, bad Monster.

Darwin after Tracey, 1974

Tropical cyclone Yasi, which is approaching the Queensland coast has, at the time of writing this post, just been upgraded to the highest severity level: 5.

This is the biggest cyclone to hit Australia in at least three generations, and is much bigger than Cyclone Katrina that had such a devastating impact on New Orleans in 2005. (Max wind speed reached: 280 km/hr, minimum pressure reached: 904 hectopascals)

Yasi is expected to touch land at about local time 10 pm Wednesday night (6 am Wednesday morning GMT) near Cairns.

After the category 4 Cyclone Tracy in 1974, which virtually destroyed the city of Darwin, Cairns has improved its building codes. But this monster is much bigger than Tracy, and the authorities are encouraging evacuation, and already, depressingly, describing it as 'deadly'.

Some data.

At the moment (NZ time 8.30am Wednesday morning), and extrapolating the information from the Australian Government Bureau of Meteorology data it is as follows:

It is about 300 nautical miles east north-east of Cairns, 300 nautical miles northeast of Townsville, moving at about 16 knots (about 30 km/hr), has a centre pressure of 924 hectopascals, swell is 14 metres (42 feet) high with some waves 28 metres high (85 feet), maximum wind speed 115 knots (213 km/hr), and still increasing in severity. When it reaches the coast of Australia, it will carry around 100 cm (36 inches) of rain to dump.

For comparison, when it touched the New Orleans coast, Hurricane Katrina was only a category 3 and dropped about a third this amount - 35 cm/ 10 inches.

Cyclone Tracey was probably just a category 5 when it made landfall at Darwin, and was a small intense cyclone at only 50 km wide. But it was particularly devastating because the eye passed directly over Darwin.

Yasi is so huge it will have cyclone-level winds across about a 400 km wide area. 'It doesn't have to be choosy' (Brett Dutschke, meteorologist, Sydney Morning Herald article today 'Yasi looms large over tiny Tracy')

Thinking of you, neighbours.