|From Wikipedia Commons
That's easy for me to answer: Wildfire. I was living in San Francisco when the Oakland wildfire of 1991 happened. I was entirely safe--there was a big body of water between me and it--but my heart was still pounding hard for hours. My logical mind could not convince my body that I was safe.
This was before the internet was anything but a few thousand nerds sending text over phone lines, I didn't own (and don't) a television, and I had no radio on, so the disaster made itself made aware to me directly. I was sitting and reading a novel in front of a window. Suddenly, the sky changed colors. The smoke cloud had dimmed the sun, coloring everything a strange burnt orange. I could hardly breathe--not because of the smoke, which was well above me, but because of the adrenaline surge. An animal urge to flee swept over me, and I had to hold on to my chair not to follow that imperative and run barefoot out of my house, trying to escape the danger. My body knew instinctively what it was. (Who knew that knowledge of wildfire was hardwired in humans, too?) I didn't have to see the flames or hear the crackling of popping trees or smell the smoke--I was still plenty scared.
It was hours before the adrenaline buzz left me, and the whole time, I thought, I'd take another Loma Prieta quake before this, any ol' day.
I also had a heart-in-throat moment the only time I saw a wedge tornado in the distance. They're mean-looking. (Beautiful, too, if kept at a distance.)
Earthquakes have been exhilarating to me. When they fade, the adrenaline rush is a positive one--like skydiving's rush or the rush I got scuba-diving when learning to doff and don. I don't mean to be insensitive to anyone who has lost a loved one in a quake, but for me, it's been a thrill ride every time. I hope I'm never in a situation where it's otherwise.
The only volcanic eruptions I've experienced have been St. Helens' minor ones from a distance (pretty, and safe if you're not right on top of it), and Kilauea (the kindest eruptions imaginable--slow-moving and lovely to view). I stood at the edge of the ocean, on the moving lava of Kilauea; as the red-hot lava at the leading edge of the flow hit the water, clouds of steam rained little glass shards over me, and it was beautiful and filled my heart with joy. I don't know that I've every felt more connected to Nature than at that moment.
I've been in three ex-hurricanes (2014, in Arizona, which should be against the law or something--seriously, Arizona? Hurricanes?) which had no more wind than any other rain storm, but I've never been in a real, powerful hurricane at its peak. They sure look scary. I've been hit by a downburst of over 100mph, while in an RV--that was a little worrisome, but it was over with in a couple minutes, and the RV was still upright, much to my surprise.
For real terror, for me, it's wildfire. I'll no doubt write a novel about wildfire within the next three years--but I suspect it'll upset me to write it, to mentally put myself into the midst of the smoke and flames.