True or False Answers
- Q. The storm that dumped hail on many suburbs of Sydney on the 28th October was a multicell thunderstorm.
A. False. The storm was a SUPERCELL thunderstorm.
- Q. Australia has the second highest occurrence of tornadoes.
A. True. Despite the perceptions displayed by the media, Australia DOES HAVE THE SECOND HIGHEST occurrence of tornadoes in the world. Yes, we do get tornadoes in Australia.
- Q. Lightning never strikes the same place more than once.
A. False. Contrary to what most people believe, lightning CAN AND OFTEN DOES STRIKE THE SAME PLACE MORE THAN ONCE. In fact, in some thunderstorms that occurred in Sydney during January 1995, I observed several examples of multiple strikes at one spot. In fact, lightning that pulsates for a couple of seconds provide excellent opportunities for rare daytime lightning photographs. The one taken at Branxton was taken during dark but daylight conditions. It was a severe bolt that pulsated for a couple of seconds.
- Q. The largest reported hail size that occurred in Australia were spawned at Kempsey with diameters of 14cm.
A. True. On the 21st of December 1991, a spotter measured a stone with a diameter of 14cm. (Michael Bath witnessed this storm at South Kempsey where stones to about 8cm diameter fell)
- Q. The safest place during a storm is under a tree so you don't get wet or your car won't get damaged by hail.
In my view, this is False. If lightning struck the tree, it can burn the tree or even split it. A car may keep you safe from electrocution but the falling tree can crush you. Definitely, several deaths and injuries occur each year from lightning strikes. People sheltering beneath trees are most often the targets. Golfers are also most vulnerable to lightning strikes as scattered trees in wide open spaces increase the probability for lightning strikes. For more information about protection from lightning, contact the Bureau of Meteorology or the S.E.S.
- Q. A common sign of approaching cold fronts are the development of cirrostratus.
- Q. Highs and lows get re-established as a result of changes in temperatures. They do not move from west to east.
A. True. Highs and lows DO get re-established as a result of changes in temperatures. They DO NOT move from west to east. Highs and lows represent the highest and lowest points of atmospheric pressure and are not moving physical systems. Weather presenters on television often refer to the eastward movement of the high and lows simply because it is more convenient than to discuss the pressure falling as a result of changes in temperature and so on.
- Q. Light green tinges in storm clouds are pleasant sights for farmers and car dealers.
A. False in my opinion. Light green tinges in storm clouds are definitely not pleasant sights for farmers and car dealers. One of the general rule of thumb for signs of hail is the so called light green tinge. At an AMOS (Australian Meteorological and Oceanic Society) meeting a couple of years ago, the theory for the occurrence of this green colouring was discussed and related to the specific structure of thunderstorms with high tops. Hailstorms do normally reach extreme heights especially in summer, but not all thunderstorms with high tops produce hail that reach the ground. In other words, do not only look for the light green tinge but combine this with the specific structure such as quickly developing dark solid bases and dense precipitation cascades. However, only report hail if you have observed it and get some idea of the size. This may be crucial for areas along the downwind path of the developing thunderstorm.
- Q. Some tornadoes in the United States have been known to reach widths of up to 1 or 2 kilometres.
A. True. Some tornadoes in the United States are so violent that small towns have almost been totally demolished. Such tornadoes have also been known to remove sections of tar from roads, scatter freight trains, and 'mow' down wide paths in heavy forested areas for tens of kilometres.
- Q. The best thing to do if a tornado approaches is to locate yourself in the smallest central room in your house.
A. True, according to the experts. (Again, check with the Bureau of Meteorology or the SES). The reason for this is that logically speaking this is the strongest area of your house with a larger concentration of wooden beams. Tornadoes often cause outside walls to cave in and therefore outside walls are not safe places to shelter. And by all means, if you are caught in the car and a tornado approaches, quickly monitor its movement before making a decision where to go. Do not simply head home as you may be crossing the path of the tornado.
lower level clouds that develop in the form of rolls or relatively thin flat layers in the form of broken patches or globules.
the section of the storm consisting of ice crystals that spreads out in the direction of the storm's motion.
airflow rushing in and up into a thunderstorm providing the necessary 'fuel' moisture necessary for storm development.
this type of thunderstorm consists of several cells in different stages of development and therefore means that the storm veers usually to the left of its cells' line of motion.
- tropical cyclone
large circulatory system (hundreds of kilometres wide) that forms over warm oceans in summer and produces torrential rain, very strong winds and causes extensive damage. It is famous for its central eye.
puffy lower level clouds with tops in the form of a cauliflower shape and with darker bases. Such clouds can further develop into cumulonimbus or storm clouds.
relatively large thunderstorm producing most of the damage associated with severe thunderstorms. It can produce large hail, wall clouds and even tornadoes and has a relatively long life span. Common features include an overshooting bulge through the top of the storm and it is energy self sufficient.
relatively small funnel like circulation usually forming at the bases of severe thunderstorms and can cause severe or total destruction to anything in its path as a result of winds reaching speeds around 300 - 400 km/hr.
wispy brilliant white cloud consisting mainly of ice crystals and is normally transparent.
- rear flank
the back section of the storm that normally is precipitation free and features cumuliform lumps and a flat base.
- wall cloud
rotating dark cloud base from which tornadoes can develop.