Houstonian here. Apparently all you need is some Dawn soap to break their surface tension!
I've always been fascinated by ants since childhood and love watching them, but these floating islands are the worst ambush I can imagine. Good to know they have a kryptonite.
Before readers run out and try this, there is a technique and protocol that should be followed, or you won't like the consequences. I'll let a post on /r/natureismetal do the typing for me [1], and here's a copy-pasta for those who don't want to click through (more scientific explanation [2] of why this works within seconds...to make sure around these bastards from hell, I gave 'em two minutes to display proof of death---put a stick in the drowned mass and lift it up---before I moved on to hunting down the next raft):
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You're all going to love this. It's environmentally friendly, it's inexpensive, it's 100% lethal, and makes them die in the most horrible manner possible.
Dish soap.
Put a tablespoon or two into a spray bottle, then add about 2-3 cups of water. Swish the water to mix. Do not shake! You don't want foam in the bottle.
MOVE. UP. STREAM. Seriously, you don't want to be downstream of this when it happens.
Now, starting in the middle of the mass, start spritzing with the soapy water, and work your way out to the edges.
The soap will break the surface tension, and act as a wetting agent on the ants. As a result, the water will now start wicking up their bodies, enveloping them like living quicksand. And with the surface tension broken, the mass of ants will start to sink.
Remember, start in the middle! This will cause the center to sink first, and drag the edges down last. The ants will all hold on to each other and drag every last one below the surface. With a soft bloop, the entire mass will drop.
Remember how I said to move upstream? If you're downstream, the entire submerged mass could end up wrapped around your legs. Where they will immediately begin clawing their way to the surface, using you as a ladder.
Best of all, you can scale up your operation, and load a backpack sprayer with a bottle of Dawn and a few gallons of water. Then just wade through your neighborhood, wiping them out for the benefit of everyone!
Fire ants are a foreign invasive species in the United states that kill animals, push out native ant species, cause incredibly painful stings, and trigger sometimes-fatal reactions in some people. They are nasty little balls of hate.
Their name was not inspired by their red color, but by their burning, venomous bites which leave huge weeping pustules. If you are allergic or sensitive, it is worse.
If you had ever been bitten, you would understand the desire to kill them if you can, any way you can.
(Bonus: According to the article, the floating ant rafts are 165% more venomous than usual. I cannot imagine.)
to put things in some perspective, they do suck, but are not as bad as a bee sting or wasp sting, at least in my opinion.
However, you are much more likely to get a bazillion bites, for example if you step in a nest and don't notice it until they are crawling up your leg..
My recollection is that you tend to not have just one bite. They are quite aggressive and tend to attack in groups. If you look at pics on the web of fire ant bites, they typically show many bites. Unless you are talking African Killer Bees, this is not typically true for bees.
I might be crazy, but I've always been sure they coordinate their bites. You generally don't get bit until several to many ants have crawled onto you, and then you get a rapid succession of bites.
You are not crazy (see other excellent comment). They are evil little beasties. I have been enjoying the descriptions here, like nasty little balls of hate and invasive species made of spite. Those are much more poetic and apt descriptions than I can come up with.
My brother was once sprayed with them by the lawnmower. He was in shorts (so his bare legs were inundated) and he reacts a lot worse to them than most people I know. I took over the lawn mowing for a few weeks after that.
I hear about this solution every time these ant-balls are discussed, but I've yet to see a video despite extensive searching. I've seen countless videos of them floating, but none with them sinking.
Has anyone found a video (or else is willing to make one :)?
I've always been fascinated by ants since childhood and love watching them, but these floating islands are the worst ambush I can imagine. Good to know they have a kryptonite.