The easiest way to reach there is to go to Fuchsia City and start surfing first to the south and then west.

These boulders have to be pushed inside a hole with the help of a Pokémon who knows the move Strength. There are 4 boulders, but only 2 of them will block currents blocking your path to Articuno.

An Electric-type or Fire-type Pokémon At least 50 Ultra Balls Hyper Potions A Pokémon that knows a move which may paralyze Pokémon or put them to sleep