Weather, like, you know, most other -- all other things, really -- is just energy. Namely, energy from the sun that creates changes in the atmosphere. But those changes can take all kinds of crazy forms. Some of them, we're talking like, nut bar. Right now out your window might be sunny or windy or cloudy or rainy; maybe it's even all of those things at the same time. But if you're seeing any of the three following things in your backyard, you're experiencing some of the most whack weather in the world.

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Number one: Atmospheric Rivers. Most of the moisture that circulated around the world, at least outside of the tropics, flows in what's called atmospheric rivers: giant conveyor belts of water vapour more than a kilometer up in the sky. At any given time, there are a half dozen or so of them flopping around in the atmosphere, but every few hundred years, a particularly huge one can produce like, ermehgerd kind of rainfall.

Atmospheric Rivers form when separate tropical storms draw a bunch of moisture together into a narrow band or filament, and high winds then shoot that moisture east like a shotgun. ARs can be four hundred kilometers wide and extend across an entire ocean, carrying as much water as fifteen Mississippi rivers.

One of the most powerful ever recorded pounded central California with unabated rain for forty three days in 1861. Now, it's not clear how much rain it produced, but it turned California's central valley into a temporary inland sea.

In the fall of 2012, a smaller atmospheric river parked itself over Wales and western England. It was a baby by comparison, but big enough to trigger thousands of evacuations. The AR phenomenon was only identified by scientists in the late 1990s, so we're just now figuring out how to predict them. But already, some are saying that the western US maybe due for an epic atmospheric river mega flood.

Number two: fire whirls and fire tornadoes. If a pants-load of water doesn't scare you, how about a twister made of fire? Fire whirls happen when super heated air from a wildfire rapidly rises into an air mass that has just enough spin to create a vortex. That vortex might form because of neighboring winds or the topography of the land, but when it does form, a fire whirl can make a bad situation much worse.

Historians think that some of the greatest disasters in history, like the Chicago Fire of 1871 or Japan's Kanto Earthquake of 1923 were exacerbated by fire whirls, creating high winds and flying, flaming debris that added to the damage. But fire whirls are basically just big, flaming dust devils. Scientists have recently confirmed that rising heat from huge fire can actually produce tornadoes. It's officially known as pyro-tornadogenesis, an it's only been documented once during an enormous 2003 wildfire in Canberra, Australia. The smoke plume from that storm was so massive that it caused cumulus clouds called pyrocumulus clouds to form, which in turn lead to a thunder storm. That, in itself, isn't exactly unheard of, but the storm then spawned a tornado, and researchers believe that the fire caused tornado was a half-kilometer in diameter, with speeds of up to two hundred and fifty kilometers per hour, as a wild fire raged around it. Ahhhh!

Number three: Ball lightning. Though long dismissed by some scientists as a myth, today, experts believe ball lightning is indeed a thing. But you can't blame them for not buying it initially. Historical accounts tell stories of grapefruit sized orbs of electricity forming usually during thunderstorms and then floating into rooms, sometimes even killing people, including eighteenth century scientist Georg Richmann.

So what causes it? Well, that's what makes it most whack of all -- we're not sure. One theory is that when lightning strikes the silica rich ground, silicon vapour may condense into particles that combine with oxygen in the air, forming a burning ball. Another idea is that static electricity in the atmosphere energizes molecules in the air, which are usually made up of gases, and then splits these molecules into ions, creating plasma. As with the other phenomena, scientists are still studying this, and we're learning more and more about all kinds of weird weather every year. So, do your part -- if you see any of this nutty business going on outside, do me a solid and text me a picture of it. Pics or it didn't happen.

Thank you for watching this episode of Scishow, if you have any questions or comments or ideas, we're on Facebook and Twitter, and of course, down in the comments below, and if you wanna keep getting smarter with us hear at Scishow, you can go to YouTube.com/Scishow and subscribe.