1. Pertaining to a sky cover of 1.0 (95% or more) when at least a portion of this amount is attributable to clouds or obscuring phenomena aloft, that is, when the total sky cover is not due entirely to surface-based obscuring phenomena.

2. Cloud layer that covers most or all of the sky; generally, a widespread layer of clouds such as that which is considered typical of a warm front.

1. An enclosed airway to permit one air current to pass over another without interruption.

2. To move overburden removed from coal mined from surface mines to an area from which the coal has been mined.