northernbird

We were in Nova Scotia in 2003 when Hurricane Juan, A cat 2 hurricane hit Halifax. It was quite honestly the most scary experience I have ever had.

Burbage

A US classified category 1 storm could be as much as cat 3 in Australia. Cat 1 and cat 2 in Australia are both below 12 on the Beauforte scale. Cat one in the US is the point where the storm crosses from 11-12 on the Beauforte scale, cat 2 in the US is the stronger end of category 3 in Aus. Cat 3 in the US is cat 4 in Aus. See the table here: http://en.wikipedia.org/wiki/Tropical_cyclone

Not sure why this is, but it allows Aus media to over-dramatise cat 1 and 2 cyclones when in the rest of the world they are just classified as tropical storms, in fact cat 1 in Australia is about the same as an average winter storm in the UK.

Alfresco

http://www.space.com/12760-hurricane...ast-coast.html

Turban Explorer

The 'category' thing comes about from building materials ratings I think. Either that or the Aussies are drama queens.

Pollyana

http://www.bom.gov.au/cyclone/about/
and
http://en.wikipedia.org/wiki/Tropical_cyclone_scales

Any tropical cyclone that forms to the east of 90°E in the Southern Hemisphere is monitored by either the Australian Bureau of Meteorology and or the Regional Specialized Meteorological Center in Nadi, Fiji. Both warning centres use the Australian tropical cyclone intensity scale, which measures tropical cyclones using a six category system. It is based on estimated maximum wind gusts, which are a further 30-40% stronger than the 10-minute average sustained winds. This is different from the Saffir-Simpson Hurricane Scale, which uses 1-minute maximum sustained winds.

Alfresco

Turban Explorer

Interesting. My parents were amused to note during my Yasi experience, that they suffer an Aussie category 2 cyclone about once a month in the Shetlands.

Burbage

The point is that if you get a category 2 warning in the USA it's a LOT bigger than a cat 2 warning in Australia.

Rambi

Interesting that they don't use the same scale.

Never heard any of the big storms we regularly get down here being categorised even though they'd be like an average winter storm in the UK.

IvanM

It seems like they are more worried about flooding than wind damage. Katrina created a big scar in the US and no politician wants to repeat the mistakes.

Rambi

So, a category 1 US is like a category 3 Aus.

I don't think they make a drama out of category 1s down here. That was why I was surprised they were making a drama about it up there. The different scale explains why.

Pollyana

In order to be categorised as a cyclone (or Hurricane) a weather system has to meet more than just the wind speed - have a look at the BoM link I posted above.
Cyclones have to form over warm water for one thing - one reason why the last Aus season was pretty active was because the water temps didn't drop as low as usual during winter, hence they were more conducive to cyclones forming earlier in the season.
The storms that impact Victoria generally form over colder Antarctic waters, and are low pressure areas, or depressions, but not cyclones. Even if a cyclonic system moves down the coast from Queensland, having started life up here as a cyclone, once it leaves tropical waters it ceases to be a cyclone as there isn't enough warmth to sustain it.

Cyclones off northern Australia typically develop between 5 and 15°S and reach maximum intensity between 10 and 20°S. As they move further south they will weaken over land or, for those remaining over water, weaken as they encounter an unfavourable environment (strengthening wind shear) and move over cooler water. They usually increase in speed as the steering winds in the mid-levels of the atmosphere increase and move to the south or southeast.
Occasionally a cyclone moves south and interacts with a mid-latitude trough and undergoes extra-tropical transition changing from a warm-cored tropical low to a cold-cored mid-latitude low. The structure, distribution of winds and rainfall changes significantly.

http://www.bom.gov.au/cyclone/faq/in...ml#definitions

Rambi

I was thinking the storms in the UK were more like the storms we get down here.

DeadVim

There are more white people in the way of this one, they'll be on their mettle this time.

IvanM

With automatic weapons.