Sadly, several months ago a similar incident in the Florida Everglades made the news. Small group of Boy Scouts were hiking from US 41 towards State Road 84/I-75 IIRC. Here in Florida the combination of heat and high humidity will often have heat indexes in the triple digits.

When you're walking in the swampy water on a 85 to 90F day, you really need to be aware of your increased need for water intake, BIG sunshade type hats as well as sunscreen etc.

It becomes a bit of a catch 22 situation, most sunscreens and bug sprays hinder your ability to easily sweat which is needed for heat relief, the high humidity hinders the ability of the sweat to evaporate and the high heat just makes life miserable and degrades your decision making abilities.

It would appear that all of these as well as some planning and preparation issues played a part in this local tragedy.

Sad and for the most part preventable.