The assessment of low temperatures and visibility is particularly important when it comes to Rafting in Tennessee. If the water is very cold, check the type and thickness of the wetsuits of the students. In any case it is better to shorten the duration of the dive and avoid having to do decompression stops. It is useful to distribute quick-release caloric foods before immersion (chocolate, sugar cubes, honey) and to keep a thermos of hot drinks at the exit (dog rose or other herbal infusions, avoiding coffee and, possibly, tea).
When the sea is rough and there is poor visibility, it is better to cancel the immersion of the beginners. For the more experienced divers: reduce the number of divers per group, supply each group leader with a lamp that is visible from at least a few meters away for current position.