Unova Roaming Tornadus .

Tornadus expels massive energy from its tail, causing severe storms. Its power is great enough to blow houses away.

In Pokémon Black, after obtaining the 8th Gym Badge then entering Route 10's Gate,
the player will be notified by the attendant that Route 7 is experiencing a bad storm.

Upon reaching a house along Route 7, the old lady will share the story regarding the Unova Roamer,
and the Roaming Encounter will be activated.