Formation of Fog, Introduction

• Forms as the RH increases to 100% - haze particles grow into fog (cloud) particles near the ground

• is really a cloud near the ground

• International definition: Visibility is less than 1 km

• NWS definition: Visibility is less than or equal to 6 miles and T-Td < 5°F

• Fog in polluted areas can be a health problem since it becomes acidic

Types of Fog:

1. Radiation Fog

2. Advection Fog

3. Upslope Fog

4. Steam Fog

Let's look at how each of these are formed......