A front having a steep slope, forcing the air that is being displaced abruptly upward, is known as a _____ front.

A front characterized by a steep slope that forces air upward abruptly is classified as a cold front. Cold fronts occur when a colder air mass pushes into a region occupied by warmer air. The nature of the cold air is denser than the warm air, which causes the warm air to rise quickly over the advancing cold front. This rapid ascent of the warm air can lead to the formation of cumulonimbus clouds and associated weather phenomena, such as thunderstorms and heavy precipitation.

Cold fronts are typically indicated by a sharp temperature drop and shifts in wind direction, often followed by clearer skies once the front passes. This abrupt lifting of air is critical in understanding meteorological phenomena associated with storm development, as it can lead to dramatic changes in weather conditions over a short period. This contrasts with warm fronts, where the slope is more gradual, and the warmer air rises slowly, resulting in more steady precipitation.