“Tornado season’s gearing up in the States, and I’m going to be doing a...”
If you're in an open space, find a dip in the ground like a ditch/large drainage pipe, yes? Also if the sky turns a weird green/yellow & gets really still & silent like there's no wind but it sounds like a train is approaching, a tornado is coming.
I would stay away from a drainage pipe, just because flash flooding is often a concern with the storms that produce tornadoes! At least with a ditch you can generally get to slightly higher ground fairly easily if it starts filling with water. Stay low to the ground and cover your head to protect it from debris/hailstones (even a penny-sized chunk of ice falling from the sky at terminal velocity can do some damage).
Here’s the thing about the green skies: generally, strong tornadoes in the Great Plains and Midwest tend to occur toward the end of the day, as the sun’s low in the sky. Hailstones have some strange refractory properties, and if everything lines up just right, sure, you can get some eerie green/yellow going on. But it’s definitely not necessary to get a tornado--in fact, a person standing on one side of the storm might see the clouds as green, and a person standing on the other side might see them as just plain dark blue! It all depends on where the sun is relative to the hailstones falling through the cloud. The green sky’s more coincidence than causative.
Likewise, the sound a tornado makes varies a whole lot depending on what it’s picking up. The train sound is one of those things that’s entered popular culture because it’s so evocative, but honestly it’s just a big wind. It sounds like a really, really intense windstorm, is all.
Some tornadoes occur with a type of thunderstorm known as low-precipitation supercells, which means that you won’t get a lot of rain and hail associated with them, and in cases like those? Sure, I can see it being fairly quiet right up until the tornado hits (although, again, it’s an incredibly loud wind and you should be able to hear it well in advance). But there are also high-precipitation supercells, which means you can have hail and rain wrapped practically all the way around the tornado. The tornadoes produced in high-precipitation supercells can be more deadly because it’s so much harder to see them coming. Don’t rely on the “calm before the storm” or that classic train sound to let you know when a tornado’s coming.
