Snowy Screen of Death

How do you know that a perimeter has been breached or that the soldiers you've sent in the alien hive have met a messy end? The screens that were giving you a visual feed have gone full of static, meaning that the cameras have been disabled or shredded, like their wearers.

This effect was the precursor to the infamous Blue Screen Of Death, and was itself an outgrowth of the dead telephone line and the radio receiving only the static of a carrier wave with no signal.

See also Camera Abuse. Related to Insecurity Camera, in which malfunctioning cameras are ignored.

Examples of Snowy Screen of Death include:

Anime and Manga

Akira: The TV coverage of the military's takeover of Neo-Tokyo.
In Magical Girl Lyrical Nanoha A's, when Clyde's Cool Starship, the Hestia, is slowly being taken over by the Book of Darkness, half the screens in the Holographic Terminal of The Bridge showing the damaged areas of the ship are shown to be in static. Clive's transmission to Gil Graham also gets cut off in static as he salutes his friend.
Paranoia Agent: When the black blob submerges the TV studio in the last episode.
End of Evangelion: When JSSDF is taking over the NERV HQ, they blow up all the outpost stations around it with artillery. This results in turning every CCTV screen at the The Bridge into static.
Averted in Dragon Ball -- the camera of the news crew remains intact, showing us that they vanished without the trace and left their clothes behind, one of the first clues heralding the arrival of the arc's villain.

Film

The Incredible Hulk: when General Ross's soldiers try to take on the Abomination.
Auditory example in Star Wars: The Empire Strikes Back -- "Imperial troops have entered the base, Imperial troops have entered----"
- Also from The Empire Strikes Back, a three-dimensional example: the bridge of one of the Star Destroyers is taken out by an asteroid strike while Darth Vader (aboard the flagship) is hosting a video conference. The hologram of the stricken ship's captain flickers and fades out.
And used earlier in Fail Safe. The President is on the phone, having ordered a nuclear strike on New York in order to prevent the Russians from launching their own nuclear attack following an accidental bombing of Moscow. The audience hears the squeal caused by the phone on the other end of the line melting.
"A communications disruption could mean only one thing: invasion." Governor Sio Bibble in Star Wars the Phantom Menace.
When The Truman Show finally goes off-air, the channel shows static. It might have made more sense to show the channel logo or commercials, but the static tells us "it's over" better.
Happens repeatedly in one scene in Alien, as the Space Marines get picked off one by one.
The China Syndrome ends with one of these, right before it goes to Silent Credits.
Happens in the movie version of Watchmen.
Poltergeist: The little girl communicating with a Snowy Screen of Death lets us know that All Is Not Well. "They're heee-ere..."
Weird variation in Pitch Black, where the monsters are blind and navigate by echolocation. When the movie screen shifts from conventional footage to static in which ghostly figures can be seen, we're "seeing" via the creatures' sonar. Still paired with death, as they're invariably stalking some poor loser when this happens.
The Expendables: When Barney shoots the camera in the customs office.
Lockout: When the negotiator sent to the SM-1 orbital prison gets shot in the head, the camera concealed in his glasses abruptly stops transmitting, and the screen at the other end goes full of static.

Literature

One of the X-Wing novels had a scene where a security expert was tracking a target by which cams he shot out. Also, X-Wings and other fighters in various media have a tendency to get interrupted in mid-transition by something (up to and including the fighter) blowing up.
The title of the novel Snow Crash refers to this phenomenon. The plot revolves around a Brown Note hidden in some static.

Live Action Television

In Doctor Who episode "The Stolen Earth", when Harriet Jones is killed by the Daleks her feed turns to static. Justified in that there was a psychic link driving the video-conference.
In the Babylon 5 season two finale, The Fall Of Night: A minor character had spent the entire season trying to find the ship that caused the death of his commander. The last shot of the season is the gun camera footage, indicating that he found it.
In the 2010 BBC adaptation of The Day of the Triffids, the flash of light that blinds most of mankind also causes a loss of TV signal, and TV technicians watch with rising alarm as all the screens go full of static.

Video Games

Some enemies in Metroid Prime, cause your visor to do this when they are close.
In Metroid Prime 2: Echoes, you see this happening on the visual log at the G.F.S. Tyr.
- Combining the above two, if your visor is drowned in static and then blips out, then congratulations, you've just killed Samus.
In the intro of Tekken 4, Kazuya is beating up a bunch of Mishima Commandos with camera attachments, while his father, Heihachi, watches incredolously from a chopper viewscreen (and with good reason, considering that he last saw his son when he threw him into a friggin' volcano, minutes before eruption). After using the camera on the last goon to declare his intention to 'Take it all back', Kazuya smashes his fist through the camera (and presumably the guy's head), causing the screen in Heihachi's helicopter to turn to static.
In The World Ends With You, the perspectives of characters who get "erased" are shown as a gray static-filled screen.
Perhaps the climax of EarthBound's Final Boss counts. There's no in-story feed, but the whole thing is such a fourth-wall-breaking Mind Screw that the static, snow, and final cutout has a similar effect. Also, the static is blood red.
When your territory is being invaded in Saints Row, a Saint will call you and ask for your help. More often than not, they'll be shot while talking to you and somehow hang up.
An audio version happens in Silent Hill as a form of monster radar: the sound of static on your radio means there's something nearby. Enjoy the Paranoia Fuel!
The briefing of the last GDI mission in the first Command & Conquer: A GDI spy with a camera has infiltrated the temple of Nod, is seen, his camera goes out in the ensuing attack.
Space Hulk showed the Marine you currently controlled in a large central window, with the other members of the team in small windows above. If/when one of them dies, their screen shows static.
In the Tear Jerker ending to Crisis Core: Final Fantasy VII, Zack's DMW, a battle mechanic that works off of Zack's memories of his friends, begins replacing scenes of his friends with snowy static, until the battle is over, and an image Aerith, followed by the entire screen, disappears into static...
When Snake is killed in Metal Gear Solid 4: Guns of the Patriots the game's video fades to static.
In Shin Megami Tensei: Strange Journey, this happens to the protagonist's demonica suit if he is killed in battle.
Whenever the player dies or transitions between levels in Mondo Agency, the screen shows a heavily pixellated static.
The Suffering and its sequel. The cameras are in on the scares. Sometimes they will only work until the proganist checks out the feed and sees something scary. Then static.
In Distorted Travesty, whenever you run low on health this effect occurs, along with the music and sound effects becoming slower/lower pitched. It's surprisingly unintrusive, especially compared with other games Critical Annoyance.

Web Comics

This Sluggy Freelance strip.
Used in Schlock Mercenary.
This El Goonish Shive strip.
In Sinfest, this happens to the Devil himself in this strip.

Western Animation

The first appearance of Shego in Kim Possible (episode broadcast order notwithstanding) is on a security camera which she destroys, then there's a moment of static.
In Transformers Animated, during a Robot War (no, not the usual robot war... Soundwave tried to start an automaton revolt.) a newscaster's camera bot goes out of control. We see the reporter running, from closer and closer. The reporter turns back in horror, and... static.
- Incidentally, anytime afterwards that a reporter is needed, they use the reporter-bot.

Real Life

The switch from analog to digital looked like this. Doubles as an End of an Age of sorts.
Actually very unlikely with real security cameras - if a CCTV camera is disabled the screens will turn black, or show a 'no signal' message. The only time static would appear would be in the event of a wireless camera being disabled, in which case the Snowy Screen of Death is a likely outcome.
Not a camera screen, but radar screens tend to do something very similar when sufficiently powerful jammers/ECM start coming online. Similar to the trope, unless the jammer is somehow knocked out, the radar emplacement is going to die very soon as a result of a bomb/anti-radiation missile down the feedhorn.