wash·out 
(wŏshout′, wôsh-)
(wŏshout′, wôsh-)n.
1.
a. Erosion of a relatively soft surface, such as a roadbed, by a sudden gush of water, as from a downpour or floods.
b. A channel produced by such erosion.
2.
a. An event or action that fails, is canceled, or ends prematurely, often because of rainy weather.
b. One who fails to measure up to a standard, especially one who fails a course of training or study.