The crux is that you can really tell how bad the scream is, how much pain the person is in, how much terror is really being expressed, from two factors: the color of the text and how jagged it is. In the above image, Blackbolt is launching (perhaps vaporizing) some foe and that foe's pained scream is rendered in black and white, with a relatively low jaggediness. I'd say this scream is dire, though not bloodcurdling. Compare to this Wolverine scream which is large, red/orange, textured, at the top of the page. That is a scream.
There's an argument to made, I think (and also supported, because I'm going on some gut feelings here), that only characters of some central focus, fighting for either good or evil, are permitted to scream the way Wolverine does in the above panel. It is only a hero–in the sense of their power, not necessarily their alignment–that warrants taking up so much page real estate with their howls. Environmental sounds, sure: make 'em big if they gotta be. Especially if they're explosions. KABOOM, KA-THOOM, KRAK-OOOM, THA-BOOM and FUH-TOW all you want, all over the page. Especially if there's a big, bright mushroom cloud accompanying. But screaming? I don't know - I get a sense it's only the important whose wails will ever go truly, textually, onomatopoetically non-linear. I'll gladly take examples to the contrary, however!
Another screaming-in-comics related conversation topic which came up applies to the gendered aspects of screaming we discussed. There's one character comparison I talked about w/ RS's producer-in-chief Hans Buetow that's particularly interesting.
Blackbolt, again: pictured above, was the one time ruler of the Inhumans and a being whose voice is so powerful, a mere whisper can topple a building. If Blackbolt were to speak at normal volume, he could level a city block and shouting, at full volume, his super-sonic scream could, according to wikipedia at least, destroy a planet.
As such, Blackbolt has undergone intense training to make sure that, even while sleeping, he doesn't make a peep. He communicates through sign-language or, with only a very few people, telepathically. He is some kind of weird ideal of the strong, silent type: a dark, handsome leader, a physical adept and so in control of his own body he is able to resist making noise even while unconscious. Only while in battle, only when it is perfectly, and entirely necessary, does he unleash a sonic event so powerful it wouldn't curdle blood so much as vaporize it. Except for that time he was mind controlled by his brother but that's... I mean... extenuating circumstances, amirite?
We could compare Blackbolt to Black Canary - a superhero from the DC universe. Black Canary wasn't born with any particular powers past a natural adeptness at combat. She's a great fighter, gymnast and motorcyclist. The continuity for Black Canary is strange, and more than a little confusing: she was one character, and then two characters (a mother and daughter, both a different version of Black Canary) and then, very recently, became a single character again. But as far as I understand... the original version of Black Canary, who was minted at around the same time as the original Blackbolt, discovered her real super power only after struck with intense grief.
Her Canary Cry is remarkably similar to Blackbolt's supersonic scream, though not nearly as powerful. And interestingly, at least at first, Black Canary couldn't control it. Only when she became upset, or was thrown into danger, did her reflexive scream turn supersonic, injuring her would-be assailants. In later Black Canary incarnations, the power was described not as a latent ability unlocked through grief (and therefore tied, in some way, to unstable emotion) but rather as the result of genetic mutation, putting it much more in the area of rationalized science. The same can be said about the television version of Black Canary found in the show Arrow: Laurel Lance's cry issues forth from a piece of technology that is worn around her neck.
The differences between Blackbolt and Black Canary are many, but I find the most interesting to be the degree of control each has over their powers. In the non-linear vocalizations episode I talked a bit about how while men may scream, they are not "screamers". Being a "screamer" means one is not in control; it is the women in horror movies who are The Screamers because it is important, for many reasons, that they are the victims (though they may not be the only ones getting killed). In short: though both men and women may scream, it is only the women who lose control.
This distinction, it seems, would port over the comic book characters whose superpowers involve screaming. Beyond 'Bolt, both Banshee (of the X-Men) and Superman have sonic scream abilities which they can control with utmost skill. Banshee even managed to completely hide his powers the whole first part of his life.
However, Siryn (Banshee's daughter) and Songbird (a member of the New Avengers) both canonically lose control of their supersonic scream abilities–and even have the potential to do great damage, either to themselves or their surroundings, in the process–if they are upset or in great distress. Black Canary also loses control but her loss of control results in the gaining of ability as well.
Of course, this isn't an exhaustive list of every character in every comic property which possesses a sonic scream. It would take much more research to really pin down the gendered aspects of Screaming As A Superpower. But I found it interesting, none-the-less, than of the six superheroes I happen to know with supersonic screams... a fine, and consistently purposeful control over that ability seems distributed only to the dudes.