Red tides are generally caused by the invasion of red and brown algae that is poisonous to the fish in certain areas and toxic to humans. If you can see a fluorescent orange glow under the water, a good rule of thumb is to avoid swimming in that location, no matter how enticing it looks. A good rule of thumb is if there are dead fish in a place, you really shouldn’t swim in the water that the fish died in.
Spying J-shaped trees on a hike or walk through the woods can be extremely confusing for the inexperienced hiker, and quite perturbing for the experienced wilderness explorer. When you see J-shaped trees, that means that the land has shifted significantly since that tree started growing. This is usually a telltale sign of an impending landslide, but that can happen at any time anywhere, seeing J-shaped trees is just a little more evidence of the looming danger.