If the water near you is salty, brackish, or just plain funky and you don't have a filter, boil it, prop your jacket over the top, and place a light rock on top to create a low point. Position your cup or vessel under that spot. As the non-potable water boils, the steam will rise and condense on your jacket then flow downhill and into your cup.
Trap air in your jacket to create a simple flotation device. Knot the sleeves and neck using overhand knots. Holding the bottom of your jacket in both hands, scoop downward, bringing the bottom hem underwater and holding it there. Twist the bottom like a trash bag to keep your air bubble from escaping.
If rain is on the way, dig a wide, shallow depression and line it with your rain shell or poncho (size your ditch to the largest panel on the jacket; you don’t want any leaks).
Knot the sleeves of your jacket (or tie them off with cordage) and use them like canteens. Sling both sleeves over your neck to carry it yoke style.
Spread your shell over low vegetation or atop a simple frame made of sticks to escape the worst of the day's heat.
Keep your feet dry
Improvise first aid
1. Dress wounds with strips of your raingear to keep them dry and dirt-free.
2. Strips of durable fabric also make good slings or bindings to splint broken bones.
3. Grab a handful of snow or carefully fill a section of your jacket with warm water to create an ice pack or a hot compress for bone, joint, or muscle pains.
Harness wind power
Use your poncho or jacket as a sail on a raft or canoe by tying it to a makeshift boom and mast, or simply holding it to catch the wind.