Exactly what I carry varies depending on the hike, weather, and who I'm with. Of course I'm not going to carry full-on survival gear when I hike a gentle, two-mile trail that sees lots of foot traffic -- but I do have a core selection of just-in-case items that I like to have along, well... just in case. I can then add or subtract from the collection to suit any particular outing.
Some of the most basic items I'll almost always have along include:
- A pocket knife, because it has so many useful applications.
- Duct tape, because it fixes almost anything -- including human skin (sort of).
- A lighter, because in an emergency fire can be a source of warmth, light, and psychological comfort; it's also a potential means of signaling for help.
- A tiny headlamp because being able to see where you're going in the dark can keep an emergency from happening in the first place, or make it easier to deal with one that's already come up. Often, I just sling a Black Diamond Ion around my neck.
- A space blanket for emergency shelter -- it's very shiny, so it's potentially helpful for signaling for rescue as well.
All that easily packs into a zip-close bag, which then slips into any jacket or cargo pants pocket. It's just habit to stick it in my pocket or pack when I stroll out the door, which means I almost always have it handy on the very rare occasions I've needed it.
Want to see the full list of what I usually carry? Click through for a look at my "full" emergency kit -- although truth be told, in case of real emergency everything in my backpack, on my person, and around me becomes a survival tool.
What's in your hiking emergency kit?
Photo © Lisa Maloney: The just-in-case bag.

Comments
Your hiking kit looks great. To make it a little more complete throw in a few bandaids, some safety pins and an energy bar. Those should easily fit in your ziplock bag.
Thanks for the suggestions, you’re spot on! I used to carry a nice, fatty candy bar in my emergency kit but have taken to stuffing that into my pack instead… it should go back in the kit! Band-Aids are always good to have. I’m curious what you’d use the safety pins for, though — fixing rips and tears in textiles?