An Australian standard for bush track was developed in 2001 in consultation with a number of out door bodies and organisations.  These Standards are used to describe the condition of the track and the terrain and give a feel for the level of experience required by people using them.

The following tables gives a bit of a feel for the tack classification standards.  I have modified them a bit from the AS 2156.1-2001 to suit the need of the website.  As well as these elements for classifying a track the standard does also outline guides for management, these include facilities to provide, publicity and intervention levels.

The pictures in this table act a a bit of a guide, but only refer to the specific element been studied (IE just the sign or gradient)

General	1  A well maintained path suitable for wheelchairs	2  A popular and well maintained nature trail	3  A well used and obvious bush track	4  An established bush track with limited signage	5  A marked trail that can become unclear in places	6  A known route with n signs and a very indistinct track if any
Track Conditions	Hard surfaced track suitable for wheelchairs. 1.2m wide. Minimal intrusions.	Modified or hardened surface. At least 0.9m wide. Minimal intrusions.	Modified surface, sections may be hard. <1.2m wide. Mostly clear of intrusions.	Generally distinct without major modification. Debris and obstacles are likely.	Limited modification,  indistinct in places. Debris and obstacles are likely	No modification of the natural environment.
Gradient	Steps allowed only with alternate ramp access.	Generally no steeper than 1:10. Minimal use of steps.	May exceed 1:10 for short sections generally not > 1:10. Steps may be common.	Limited to environmental and maintenance considerations.	May include steep sections of unmodified surfaces.
Signage	Signs for interpretation used frequently. Arrow markers used at intersections.		Signs and track markers used for direction. Limited signage for interpretation.	Minimal signage for management and directional purposes.	Signage is limited and only for management purposes.	Signage is generally not provided. But may still be track markers.
Infrastructure	Generally includes facilities such as seats, lookout platforms, safety and hand railing.		Generally facilities are not provided expect to deal with particular safety and environmental issues.		Generally facilities are not provided expect to deal with particular safety and environmental issues.	Generally facilities are not provided.
Terrain	No previous experience required, exercise normal care.		Need no bushwalking experience and a minimum level of specialized skills. May encounter steep slopes, unstable surfaces and minor water crossings.	Require a moderate level of specialized skills such as navigation. Require maps and navigation equipment. Need to be self-reliant, in particular for 1st aid and adverse weather.	Require a high level of specialized skills such as navigation. Require maps and navigation equipment. Need to be self-reliant, in particular for 1st aid and adverse weather.	Users require previous experience in the outdoors and a high level of specialized skills such as navigation. Require maps and navigation equipment. Need to be self-reliant, in particular for 1st aid and adverse weather.
Weather	Not applicable		Forecasted and unforecasted storms may impact on navigation and safety	Forecasted and unforecasted storms and severe weather may impact on navigation and safety	Forecasted and unforecasted storms and severe weather may impact on navigation and safety

A walk is then classified based on the higest class number found.

In this table below you will see the range of assessments made for a particular track ranged the full gamut but generally sat around class 3.  But because the one element of weather ranged from 1 to 4 then this walk will be ranked a 4. However if in the summer months the weather class never extends beyond 3, then you could class this was as a 3 in summer and 4 in other seasons.

Please see the AS 2156.1-2001 standard for more information.

You have heard it said that “It’s not the heat, it’s the humidity” Well, actually it’s both. Our bodies dissipate heat by varying the rate and depth of blood circulation, by losing water through the skin and sweat glands, and, as the last extremity is reached, by panting. As the body heats up, the heart begins to pump more blood, blood vessels to accommodate the increased flow, and the tiny capillaries in the upper layers of skin are put into operation.

The body’s blood is circulated closer to the skin’s surface, and excess heat drains off into the cooler atmosphere by one or a combination of three ways…

• radiation,
• convection, and
• evaporation.

At lower temperatures, radiation and convection are efficient methods of removing heat. However, once the air temperature reaches 35°C, heat loss by radiation and convection ceases. It is at this point that heat loss by sweating becomes all-important. But sweating, by itself, does nothing to cool the body, unless the water is removed by evaporation (sweat changing to water vapor). The downside of this method of cooling is that high relative humidity retards evaporation.

Relative humidity is a measure of the amount of water vapor contained in the air, divided by the maximum amount the air can hold, expressed as a percent. A relative humidity of 50% means the air contains ½ of the water vapor it can actually hold. The maximum amount of water vapor the air can hold is dependent upon the temperature (the “relative” in relative humidity). The higher the temperature, the more water (actually water vapor) the air can hold. For example, air with a temperature of 0°C can hold about 4.5ml of water. Air with a temperature of 26°C can hold about an 30ml of water.

So, what does this all mean? Sweat is evaporated (changes from a liquid to a gas, i.e. water vapor) when heat is added. The heat is supplied by your body. The results are summed up in the table below…

We, at the National Weather Service, as part of our mission for protecting life and property, have a measure of how the hot weather “feels” to the body. The Heat Index is based on work by R.G. Steadman and published in 1979 under the title “The Assessment of Sultriness, Parts 1 and 2.” In this work, Steadman constructed a table which uses relative humidity and dry bulb temperature to produce the “apparent temperature” or the temperature the body “feels”.

We use this table to provide you with Heat Index values. These values are for shady locations only. Exposure to full sunshine can increase heat index values by up to 10°C. Also, strong winds, particularly with very hot, dry air, can be extremely hazardous as the wind adds heat to the body. The Heat Index Table is below.

Remember, these values are in the SHADE. You can add up to 10°C to these values if you are in direct sunlight.

The chart below tells you the risk to the body from continued exposure to the excessive heat.