A seal for a rotary machine includes a flexible element extending circumferentially about a rotor and extending generally radially from a first end to a free second end. The flexible element is coupled proximate the first end for rotation with the rotor. The flexible element extends at substantially a first angle between at least an intermediate portion of the flexible element and the free second end when the rotor is operating at less than a critical speed, such that a clearance gap is defined between the free second end and a stationary portion. The seal also includes a retaining plate having a stop that orients the flexible element at a second angle proximate the free second end when the rotor is operating at equal to or greater than the critical speed, such that the flexible element forms a dynamic seal between the rotor and the stationary portion.