Here's one more link. A few more details, but nothing about what the lady was wearing. http://www.630ched.com/News/National/Article.aspx?id=206097

Without knowing more about her clothing and level of fitness, it's hard to make any useful comment. I would only speculate that she may well have survived with clothing that was better suited to the situation.

She certainly was a tough lady. 60-70 km in mud, in that temperature range, without food and suitable clothing, is a recipe for misery. And tragedy.

In a situation like that, it's pretty easy to get wet from a slip and fall, a light rain shower, a bit of sweat, and even falling dew/frost. Combined with inadequate clothing, lack of food, stress and exhaustion, and you have a cascade effect. Hypothermia can sneak up on the unwary pretty darn quick.