What typically leads to the dissipation of up-slope fog?

The dissipation of up-slope fog is primarily associated with the ceasing of the up-slope wind. Up-slope fog forms when moist air is lifted over topographical features, such as mountains or hills, causing the air to cool and condense into fog. This occurs when winds blow up the slope, bringing in moisture-laden air.

When the up-slope wind ceases, the conditions that sustain the fog are disrupted. The lifting and cooling of the air that contribute to fog formation are no longer occurring, which allows for the fog to dissipate. Without the continual influx of moist air and the associated lifting, the air can begin to warm up and mix, leading to the evaporation of the fog.

In contrast, an increase in wind speed may help to disperse the fog by promoting mixing and evaporation, but it doesn’t directly terminate the conditions needed for fog formation. A change in temperature can contribute to fog dissipation but is often a secondary effect resulting from changes in wind conditions rather than a direct factor. The duration of fog presence does not intrinsically cause dissipation but rather reflects how long the fog has been maintained by prevailing conditions. Therefore, the termination of the up-slope wind is a decisive factor in the process.