As long as Blaziken’s remaining HP is 40 or less, Blaziken does 40 more damage to the Defending Pokémon (before applying Weakness and Resistance).
[C] Searing Flame: 10
The Defending Pokémon is now Burned.
[F][F][C] Damage Burn: 50+
If the Defending Pokémon already has any damage counters on it, this attack does 50 damage plus 20 more damage.