PDA

View Full Version : Want to see what's coming? Wilma


George
10-19-2005, 03:35 AM
http://weather.unisys.com/satellite/sat_wv_east_loop-12.html

Experts say Wilma is stronger than Katrina, and she's going to Florida, but not for vacation.

Regards,

George

annc
10-19-2005, 11:06 AM
http://weather.unisys.com/satellite/sat_wv_east_loop-12.html

Experts say Wilma is stronger than Katrina, and she's going to Florida, but not for vacation.

It's just been mentioned on the news here as the strongest ever in the Atlantic. It's apparently heading slowly towards the Yucatan Peninsula.

George
10-19-2005, 01:27 PM
It's just been mentioned on the news here as the strongest ever in the Atlantic. It's apparently heading slowly towards the Yucatan Peninsula.

http://www.iris.edu/seismon/

Ann,

I was looking at this map of earthquake activity, and it made me think of you. Look at Australia--it has a ring of earthquakes around it, but not the mainland itself, except for some more than 15 years ago and in unpopulated areas. Do you ever wonder, with all those earthquakes going around the rim of Australia, is it likely one could hit home??? I read that the ozone layer there is not expected to get worse, so you have that.

Regards,

George

annc
10-19-2005, 03:39 PM
http://www.iris.edu/seismon/

Ann,

I was looking at this map of earthquake activity, and it made me think of you. Look at Australia--it has a ring of earthquakes around it, but not the mainland itself, except for some more than 15 years ago and in unpopulated areas.The people of Newcastle might disagree with you there, George. They had a major earthquake that caused loss of life.

However, you are right that Australia is very stable. It's a very ancient land mass - part of Gondwana - and there are no plate edges underneath the mainland. There are occasional tremors, but as most of the country is desert, there is only a small area that's heavily populated, all on the coast. The only exception to that is Canberra, and many Australians would not consider an earthquake in Canberra to be a disaster. ;)

Richard Hunt
10-20-2005, 08:15 AM
But the top end and most of the northern coastal area is vulnerable to tropical cyclones. Was it 1969 that Dawin got flattened?

Worryingly, the city has now rebuilt and doubled in size using, mostly, exactly the type of building that's vulnerable to cyclones.

Richard

annc
10-20-2005, 12:22 PM
But the top end and most of the northern coastal area is vulnerable to tropical cyclones. Was it 1969 that Dawin got flattened?Tropical Cyclone Tracy hit Darwin on Christmas Day 1974.

Worryingly, the city has now rebuilt and doubled in size using, mostly, exactly the type of building that's vulnerable to cyclones. Where did you hear that? There was a lot of research done after Tracy, and the very latest (at the time) Cyclone-resistant building methods were used. As much of the houses were Commonwealth Government owned, these building standards were adhered to. There was a lot of publicity thereafter on the cost of buying or building a house in Darwin because of the cyclone-safe building standards required. While the Northern Territory now has its own government, I haven't heard anywhere, either in Darwin or elsewhere, that the standards have been relaxed.

Interestingly, one of the things they found in their examinaation of the city after Tracy, was that those houses with trees up to roof height survived the cyclone, whereas those without the protection of trees were turned into matchwood. So while the houses are still largely two storey to get the advantage of cooling breezes, most of them have shrubs and trees up to roof height, making it a very attractive city.

In January 1974, Cyclone Wanda crossed the Queensland coast north of Brisbane, degenerated into a rain depression, and dumped huge quantities of rain on the catchment area for the Bremer and Brisbane rivers. As the wall of water travelled down the Brisbane River, it met the storm surge from the erstwhile cyclone as it came up the river from Moreton Bay. The meeting of the two was in the central business district of the city, causing the areas around the river to become flooded. large areas of low-lying suburbs also went under water - not just to floor level. but above roof level! At the time, this was barely reported in the media in Sydney, Melbourne and Canberra. I was working as a commonwealth public servant at the time, and my boss in Canberra decided a few days later that he would come up to visit! As he'd never been to Brisbane before, he didn't notice that his taxi driver had to take a wide detour on the way to the city from the airport because the usual road in was mostly in the river. He was amazed when we showed him the newspaper photos of the floods only a few hundred metres from our offices, and smelt the raw sewage in our basement, which was below the flood level. That smell persisted for many years in areas of the city that had been inundated.

Richard Hunt
10-22-2005, 08:26 AM
I am probably wrong. The nits of Darwin which we see on TV tend to be the town centre, and there seems to be a lot of the lightweight building technique. I have nlt been t here and doubt I ever will.

Richard

annc
10-22-2005, 03:52 PM
I am probably wrong. The nits of Darwin which we see on TV tend to be the town centre, and there seems to be a lot of the lightweight building technique. I have nlt been t here and doubt I ever will.

RichardLightweight materials in construction don't necessarily indicate that a building will disintegrate in high winds. http://desktoppublishingforum.com/bb/images/smilies/wink.gif In Darwin's climate, you need materials that will not hold the heat of the sun, and plenty of louvres etc. to let the breezes through. It's the frames that have to be cyclone-proof, and the cladding material has to be securely attached.

Down here, we don't have to be cyclone-proof, but we do have to have our roofs bolted down. I can see the bolts attached to the concrete stumps of my house, although I do fear that I could lose the corrugated iron in a really bad blow. When my house was built, only roofing nails were required. These days all galvanised iron roofs are screwed down.