Barometric pressure is measured on maps in isobars. They look surprisingly similar to contour lines on maps, and join together points of equal air pressure. Wind runs parallel to isobars and wind intensity can be measured by the closeness of isobars (the closer the isobars, the stronger the wind).
High pressure systems rotate anti-clockwise and slightly outwards, are generally stable, are big, fat and relatively stubborn. They contain air that has been warmed up and is sinking, and tends to hold onto most of its moisture. In general, think fine, stable weather. Low pressure systems rotate clockwise slightly inwards, are generally unstable and smaller, uptight and aggressive, moving through quickly and with impact. They contain rising air that is continually cooling and unable to hold onto it’s moisture. In general, think cooler, windy weather with a greater chance of rain.
With this in mind, both types of weather systems will pick up moisture over the ocean, and will be without moisture if rotating over land. Consider this…. Northerlies in Adelaide are generally hot and dry, (‘straight off Uluru’) and southerlies are cold and wet (‘straight off Antarctica’).
Fronts are where 2 different air masses meet. They generally indicate a change (for the worse) in the weather. South Australia generally sees only cold fronts. TAKE NOTICE!
Clouds bear moisture and hold secrets to the weather ahead. Not all clouds bear rain, you will need to develop an understanding of which ones do!
High, thin and wispy clouds called cirrus indicate the end of fine weather, with a change approaching. Bad weather is born out of temperature changes in large fluffy clouds called cumulus. Storms are born out of really large cumulus clouds called cumulonimbus. Thicker darker and lower clouds called nimbostratus can bring heavy rain.
The South Australian bushwalking season is from 1 April to 30 November. Fire Bans are issued on days of extreme fire danger. Parks and forests are closed on days of extreme fire danger, please respect these warnings. Fire ban information is available on most weather reports and from National Parks and the Country Fire Service (CFS). The CFS hotline/information number is 1300 362 361.
Bushwalking in South Australia is best done in autumn, winter and spring. We have hot, dry summers that make the bush not only uncomfortable to bushwalk in, but positively dangerous due to the real risk of bushfire.
If you see smoke while out walking in the bush, leave the area and report it.
While evading, keep to tracks and trails if possible.You will move more quickly and may find help from fire fighters.
Should you be trapped in a bushfire, your two major threats come form radiated heat from the fire, and poor decision making through panic. Try to stay calm to make good decisions. The most intense radiation will only last one or two minutes as the fire front passes.
To maximise your chances, you will have to try to find cover. Cover as much of your exposed skin as possible. Consider sheltering behind or under rocks, trees, ditches, fallen logs or creek washouts. Think about what you are wearing, ensure it is not flammable!
Before the fire arrives, if possible, stock up your water supplies and drink as much as you can. The heat will seriously dehydrate you.Wet a cloth to cover your nose, mouth and eyes from the intense smoke and superheated air.
Do not try to run through flames unless it is small and you are wearing exceptional protective clothing.
Never climb into water tanks. Once immersed in water, the body will quickly absorb heat from the water. If the ambient air temperature is in the high thirties and a bushfire raises the temperature of the water a further ten degrees, the water/body temperature will be deadly.
Remember… Fires burn quickly uphill and on ridgetops, and usually move slowly downhill. OBSERVE FIRE BANS!
Bushwalking Leadership South Australia, in putting this information together, does in no way suggest that this is the ultimate guide and STRONGLY recommends anyone interested in bushwalking to educate themselves in the dangers involved with this activity.
Bushwalking Leadership SA STRONGLY advocates first aid training and recognised outdoor leadership training before leading groups of any sort of bushwalking.
This information is intended as a prompt or introduction to some of the basics of enjoyable bushwalking.
Trails are provided for your enjoyment and should only be used in accordance with the Code. Trail users must be adequately prepared and obtain relevant information and maps. The trail conditions may vary from time to time, and trail users are advised to check weather conditions prior to leaving. Persons should use caution at all times when using trails in South Australia.
This information was originally published in 2004. View credits.