CS2 Flash Lineups and Pop Flashes

The flashbang is the only grenade whose entire value is in timing. A perfectly-placed flash thrown a second early does nothing; a scruffy one thrown at the right moment wins the site.

How blindness is calculated

A flashbang blinds based on where the detonation is relative to where you are looking and whether anything is between you and it. Looking straight at one at close range gives close to the maximum — a little under five seconds of full white, then a fade. Turning away, or having a wall corner between you and the flash, cuts it down sharply, and at the low end it is a brief wash you can play through.

Price: $200
Carry limit: two — the only grenade you can hold more than one of
Maximum blind: a little under 5 seconds

Because two are allowed, flashes are the grenade a team can afford to spend generously. Two players with two flashes each is four chances to open an angle; the same money in molotovs is one throw.

What makes a pop flash

A pop flash is one that becomes visible to the defender at almost the same moment it detonates, so there is no time to turn away. That is achieved by bouncing it off a wall or lobbing it over an obstacle so it spends its fuse out of sight and appears already exploding. A flash thrown in a clean arc through open air is visible for its whole flight and gets turned away from every time.

This is why flash lineups are worth having as lineups rather than as feel: the bounce is the whole trick, and the bounce is exactly what is hard to reproduce by eye.

Not blinding your own team

Say it before you throw it, every time. A support flash that blinds your own entry is worse than no flash — you have removed your own player and told the defender someone is coming.
Throw from behind the player entering, not beside them. A flash that detonates in front of your teammate is on their screen too.
Turn away yourself. You are not immune to your own flash, and the reflex to watch where it lands is the reason half of self-flashes happen.
Prefer over-the-wall flashes when supporting. If the grenade is never in your teammate's view, it cannot blind them.

When not to flash

Against a defender holding a long angle with an AWP, a flash that does not fully blind them just tells them the round is starting here. Against a player already in a fight, a flash risks their opponent — your teammate — as much as them. And on a save round, the $200 is worth more next round than the half-chance now. Utility discipline is a real skill and it is mostly the discipline not to throw.

Flashing for yourself versus flashing for the team

A self-flash is one you throw and then push behind yourself. It is the harder of the two, because you have to turn away from your own grenade and then turn back into an angle you cannot see while it detonates. It works, and it is how a solo player opens a position, but it costs you your own vision for the moment you are most vulnerable.

A support flash is thrown by one player for another, and it is strictly better when it is available: the entry keeps their crosshair on the angle the whole time, and the flash comes from a position the defender is not watching. The cost is that it needs communication. "Flashing" before you throw, and "in" as it leaves your hand, is the entire protocol and it is enough.

What to do when you are flashed

Do not stand still. A blinded player who stops moving is a free kill; a blinded player backing into cover usually survives.
Keep your crosshair where the enemy will be. Blindness ends before the round does, and you want to come out of it aiming at something rather than at a wall.
Listen. The blind is visual only — footsteps, a defuse, a grenade pin are all still there, and most players ignore all of it while waiting for their screen to come back.
Do not spray blindly at where you think they are unless you are holding an angle they must come through. Otherwise you have given away your position for nothing.

Counter-flashing

The counter to a flash is another flash. A defender who hears a flash coming and throws their own into the same space blinds the attacker who was counting on walking into a blinded site. This is why holding one flash back on the CT side is worth more than it looks on the buy screen — it is not for opening anything, it is insurance against the execute.