Frost Hollow

During calm, clear nights, heat radiates quickly away from the ground surface, resulting in rapid cooling. The lowest layers of the air, in contact with the ground, are then chilled more quickly than the layers above. Because cold air is denser than warm air, it tends to settle within dips and hollows. Often in winter, hilly areas can be several degrees above freezing point at night, while the lower-lying valleys can experience a sharp frost - hence the term: ‘Frost Hollow’.