It is hard to understand an "experienced" hiker going on an all day hike with virtually nothing in the way of gear to deal with the normal things that happen when you are out hiking especially this time of the year.

Just some emergency ponchos might have kept them dry enough to survive.

I have often said I am only really afraid of three things out in the woods, - getting wet, getting lost, and the dark.

I carry a poncho of some sort and a space blanket in case it rains on me, multiple compasses and a map to help me get unlost, and at least two flashlights.