If you've ever been against a good jungle Olaf, you probably know how devastating he can be... his clear speed is insane with blue and his ganks are annoyingly strong if he lands his first Q, which if you go too far to dodge you'll be worse off than having been hit. So... what are some ways to counter him? As a mid laner? As a jungler?
He simply is strong. Its like saying "what counters a shyvana jungle". well... nothing. His ganks are strong. Ward correctly and push out (its really hard to gank for a olaf if the lane is pushed, cause if he comes form behind and throws a axe, he has to run past you to pick it up -> easy escape), or alternativly freeze the lane as long as possible, since Olaf is strongest in the early- mid game phase (first 4-5 lvls). Dont invade, he will destroy you. As mid or jungler, ward your own jungle entrances, if he trys to counterjungle get him with 3-4 people. Since most Olafs take Ghost, he is actually fairly easy to kill if you "find" him in your jungle, since he cant just flash over a wall. If you know the enemy is jungling Olaf in champ select, pick Champs that have early escape or high mobility champs in general (Ahri, Gragas, Galio for mid, Shyvana, Lee Sin, Noc for jungle) and just avoid fighting him in the early lvls.
EDIT: Jungle Olaf is REALLY blue dependend. Means after lvl 7, he is not that big of an problem anymore. If you have a really really strong lvl 1 setup, you can invade and get his blue, resulting in him beeing weaker through the rest of the game. Dont try this if your lvl 1 isnt really good, cause Olaf himself is a beast lvl 1, spammable, 2 sec cd aoe nuke with his Axe will win him nearly every lvl 1 fight.
How to counter Olaf Top?
tl;dr - Very hard/Impossible
It depends from his summoner spells. If he has Ghost this means that he is unable to dodge your poke damage - focus on building that. If he has Flash he can't chase you down with Ragnarok - rush boots and laught at him trying land his Q.
But general tips is buy early boots and take great ranged poke champ... if it fails be ready for line swap with bot.
Boots make able you to easier dodge his Q - only CC skill that he has. Without this slow you should be able to run away and control fight. After few missed ones especially at early game Olaf should start be more conservative about using his abilities.
Generally speaking everything that can harass or poke him in the lane is good. Most viable counter picks are Teemo with his great poke is allways viable anti brusier pick or Yorick that is designed to be hard AD Brusier counter or Nidalee that is impossible to catch.
Swap lines and make him run with poke damage dealt by your AD Carry. If AD Carry has good escape mechanism (Ezreal, Corky) he will not win after lane.
How to counter Olaf Jungle?
tl;dr - Not so scary if played properly
In general - your jungler must be better than Olaf making him "babysit" one of lines.
Wards. He is not invisible so if you play on top ward place from 2-3 minute and after all your wards expire polite ask your jungler to help you with this task. If you are playing bot - this is a task for support. If you are mid you shouldn't be afraid so much - but have in mind that your CC doesn't work on him and do not blindly trust in this. I saw Ryze who think that his rune prison will make him safe. Nope.
Boots as I explained it earlier. Mobility is key to counter Olaf IMO in all lanes. This is important for AP Casters on mid that now, in preseson 3, buy boots after 2 or 3 items. You can't do that this time!
Control his first 1-3 blue buffs. Jungle Olaf without blue is weak in early game. In mid game he don't need it so much but Olaf without assists or kills will be weak part of your enemy team.
It is dangerous to go alone against Olaf with 2 gigant belts. Build Blade of the Ruined King if you are AD - Your attacks deal 4% of the target's current health in physical damage and heals you for half the amount. This will hurt Olaf.
WARDS! I don't beleive that he's a good ganker because he only has a slow, and unlike Shyvanna or Mundo he can't run exhaust. Just ward enemy wraiths and ask your jungler to ward the other side on the river. He can't gank from the lane. If you still fear him, then get a mid lane with an escape: Kennen, Fizz. these two are almost impossible to gank if played smart.
There are a few things that can fight a double buffed olaf. Lee sin is pretty good if you're planning to invade. The most important thing to do if you want to shut Olaf down, but this is more of a general tip, is to deny them their buff camps and or kill them at their buff camps. Olaf is vulnerable to this because he tends to be very low in the jungle. Something like Shyvana or Lee Sin is what I would invade with, and kill him at his red. As a mid laner, Morgana, Ahri, generally anything that has some method of escaping his ganks. Olaf hates being kited.
Very good counter olaf is Jarvan (if we talk about jungle).
he can escape very easily from Olaf's axe + he does good dmg and his ulti is very good.
Mid Olaf? Never seen that :)