What was the most dangerous thing you have encountered while hiking/climbing? Was it a lose rock on a steep ledge? Sudden lightning storm? Or maybe some kind of animal?
Mine is the third. I was on Guadalupe Peak Trail and, on my way back down, I heard one of the scariest noises possible while hiking in the dessert. I had come across a northern black-tailed rattlesnake. Every Texan knows that all rattlesnakes are deadly w/o medical attention. This one, however, is a real asshole. I was told two days later at a rattlesnake exhibit that snake died NOT have an anti-venom. That is the most dangerous thing I have come across while hiking.

I've encountered approximately 1 rattlesnake per year since the early 1970s. They are almost always easy to walk around and I've never felt like my life was in serious peril from them.

But...

Yes to all of the other dangerous things that you named (close bear encounters, gnarly stream crossings, rockfall, exposed scree covered ledges...). To me, lightning is the scariest- even though the actual level of danger may not be as high as the other situations that I just mentioned. I hate the randomness and the lack of control one has during an intense thunderstorm- especially above timberline.

But...

Having said all that, I'm pretty sure the the most danger that I'm exposed to on any trip to the mountains is from other drivers during the drive to and from the trailhead.

I've come across about a dozen rattlesnakes over the years. One was coiled and ready to strike, another was getting ready to coil. The scariest was almost stepping on one sunning itself, not aware I was even there. I saw it at the last moment and stepped beside him. Most of the rest were far enough away to not cause fear. I've scared up one bear, and seen about four others from a distance.

I'm usually more concerned about bees. You can happen upon a hive unknowingly and boom, they can swarm. It hasn't happened yet but I have found myself amid a few bees in a miniswarm, suggesting more may be nearby. So I exit out, slowly.

I encountered Mexican coyotes once. That wasn't as scary as I might have thought.

I tend not to be partial to lightning, either.

"Most dangerous" is a broad and versatile term.

I've come into contact with irate, possibly armed, landowners while trespassing on their land while hiking. That's pretty dangerous. I've gone bushwhacking around areas known for violent pot farmers. Also, quite dangerous.

I've climbed some pretty sketchy things, mainly in the American desert southwest. Some of the most dangerous parts of these climbs were the anchors I have trusted my life with. This was especially dangerous before I learned how to add bolts or pitons to existing, old, decrepit anchors. Try ascending a rope up a pitch, only to arrive at the belay and discover that whole time that the anchor you were hanging off comprised of two shaky pitons slowly oozing out of a loose sandstone crack. That's pretty dangerous.

I free solo regularly on climbs I have done dozens and dozens of times and are well within my climbing ability, but still very dangerous.

One time I topped out a desert tower directly underneath a small but intense electrical storm, and got shocked by touching a carabiner that was attached to my harness.

I've had countless close calls with rock fall.

Run-ins with wildlife never make me feel threatened compared to what I have listed above. Black bears always immediately run away when I see them. I have literally stepped right over countless rattlesnakes, and though startling, have never feared for my life.

It's just part of the deal, when you begin to push your limits and dive into more serious outdoor endeavors, it's going to be dangerous to some degree.

Once while hiking with friends the weather took an unexpected change and we had light rain followed by lightning. This was in the Summer when the ground was really dry. We were thankful that the lightning did not start a wild fire, it has done just that many times up on the Moors.

I've had folks ready to fight me because I call them out on leash laws on trails. Big pet peeve of mine is the arrogant pet owner who feels their pet is above the law.

Last year round about this time I saw my wife slip right in front of ma on the knife-edgiest part or a not so kife-edgy ridge as we were nearing the end of our day hike (less than half a mile left). She fell for about 200 feet not able to stop her fall. In the end she "only" broke her hand. And our vacation was ended on day three of three planned weeks ...

I guess if we count other people in "most dangerous"... I almost got beat up by seven guys working on some structure on top of Toro peak in Southern California. The peak is on Indian Reservation land, but a road goes to the top. I walked past them, figuring no big deal, but they surrounded me, and their leader was in my face about being on "Indian land" (like he actually cared), and told me in no uncertain terms to turn around and start walking.

A year later, I went back to tag the top properly. Nobody there that time.

Other than driving to and from trailheads, I think a few falling rocks due to melting snow on Mt. Shasta was the most dangerous thing I have encountered. Hightailing it out of the chute they were coming down was the only solution I could come up with.

I haven't done anywhere near as much as most people on here, I had also never walked up on a rattlesnake before. I would love to be able to say I had to use a weak anchor or worry about falling rocks because I would have more on my 'c climbing résumé.

Nowhere to hike in Emory.

I once was crossing the Escalante 'river' (more a muddy yellow creek) near Neon Canyon in Utah and was a bit confused because though the water was about 3 feet deep, the bottom kept falling away, being the consistency of pudding. After some effort trying to make progress, I was able to get my foot on a half submerged tree branch and hoist myself out of the goopy morass and across. Only afterwards did I realize that I had just had my first encounter with quicksand.

Most dangerous? How can you compare and rank dangerous experiences?

Here are some of my most dangerous experiences, but I can't rank them

- Caught in a lightning storm on a high summit and electrocuted for 20 minutes
- Accidentally dropped my bivy gear on day 2 of a four-day winter big wall solo
- Swept off a mountain in an avalanche trying to ski chutes
- Hit in the head by rockfall and almost knocked unconscious while free soloing
- Climbed a pitch of 5.7 vertical, horribly loose ash conglomerate with no belay above or below
- Engulfed in a rock avalanche at night in total darkness - all you could see were the sparks...
- Free soloed a pitch I knew I couldn't down climb, and then found that I couldn't go up either
- Did a pendulum 2,000 feet off the ground where the belay anchor was a loose flake
- It's a bad day when you tie off a baby knife blade piton to really "beef up" the belay anchor
- Ever try a "scree bollard" for a belay anchor?
- Removed my shoe laces for rap anchors
- Jugged a stuck rap rope that had jammed when we pulled it
- Walked several miles on a glacier unroped and then fell through to my armpits over a 50-foot wide crevasse
- Did multiple trips with heavy loads through the infamous "Valley of Death"
- Climbed knife edge ridges and cornices with no belays and no protection
- Descended North Dome Gully "Death Slabs" at night
- While jugging ropes on an Alaskan big wall, car-sized boulders started bouncing down the cliff all around us

Shall I keep going?

Ouch, jesu!
A hooker in the Philippines did something similar to me once. Or was that Thailand?....

The last time I added them up there were 14 times I could have died or been seriously injured, The majority of those were rockfall, both natural and human caused. Lightning came in second. I can add a couple of water crossings and a major avalanche that we started but one of the most dangerous things I can think of was the simple act of retrieving water, The temperatures had been as cold as 40 below zero and the river bottom had a foot of clear ice on it. We had to descend an 8 foot snowbank to get to the flowing water on top of the ice. A slip would have led to an endless whitewater ride in 33 degree water on top of an ice surface. The walled-in river would have been a sure death trap. We had to make several trips for water during our stay and it was way more dangerous than anything we encountered on our winter climb.

bob