An integrally bladed disk includes a rotor disk and circumferentially spaced first and second blades. The rotor disk has a rim the periphery of which forms a flow surface. The first and second blades extend integrally outward from the rim. The rim defines a trench in the flow surface between the first and second blades aft of a leading edge of the rim. The trench extends axially forward and rearward of a leading edge of the first blade.