At the cold front, the cold air cuts underneath the warm air and forces the warm air up a much steeper angle. At cold fonts the air is cooled quickly and forms a narrow band of thick cumulonimbus clouds.

These produce a short burst of very heavy rain.

Occluded fronts are found when the cold front has caught up with the warm front and pushed the warm air up into the atmosphere. This warm air cools and condenses.

Occluded fronts also make a short period of very heavy rain.