From Bushwalk Australia

The two related terms 'exposure' and 'exposed' have several different meanings in bushwalking contexts generally derived from vulerability (ie, exposure) to some element of danger:

• Tracks or routes that include sections along the edge of a high cliff, or which sidle along part way up a very steep high slope are said to be 'exposed' and walking (or scrambling) along such tracks involves 'exposure' (ie, exposed to unprotected heights with danger of falling).
• Camp sites that have little or no protection from bad weather are often referred to as 'exposed' (ie, exposed to strong wind or other dangerous weather conditions).
• Hypothermia (the conditon of the core body temperature being below the normal/safe temperature) is sometimes called 'exposure', probably because it is usually caused by prolonged exposure to extreme cold/wet weather.