When Avalanche is on the other team, there are plenty of fun ways to counter him. Spend the early game killing him and use his 400 gold bounty to get a tier or two. Buy demolishers, which do extra damage to his fortified armor. Get a feel for the duration between attacks and the cooldown on Blink so you can taunt him with your running hero whenever he tries to snipe you. Tell your unused melee troops to Hold Position so they don't run to attack him. Move melee units away if he tries to Blink closer. The simplest way to defeat Avalanche is to suicide his base early on.
Avalanche costs 2000 gold as of 5.3, and is classified as a special hero, which means he is removed from the tavern and the Random pool after two minutes.
Lard of Layers
This skill provides bonus armor and hurts melee attackers -- it's like a personal combination of Devotion and Thorns (it stacks with them too). Since the skill set of Avalanche was replaced, many players now maximize this skill.
Thorns hurts melee enemies who attack Avalanche and his army. This is a must-have skill when your army is being used because no one can "turn it off" unless they kill Avalanche. It's much easier to kill a Keeper with Thorns than an Ava with Thorns.
Devotion provides additional armor to Avalanche and units around him. Avalanche doesnt benefit that much from armor at early levels. However, your units will be grateful if you provide them with some defense.
Avalanche reincarnation was replaced with Critical strike as of v5.0. This makes avalanche a much better hero killer late game because you have a chance to kill the hero with one hit.