Related Clues:

• Vision obscurer outdoors
• Obstacle to visibility
• Hazard for takeoffs and landings
• It 'comes on little cat feet,' per Carl Sandburg
• Low-visibility forecast
• Dense mist
• "Pea soup" weather
• Low-hanging clouds produce it
• Mist relative
• Cloud you can walk through
• Gothic novel trope
• Skyline concealer
• Weather phenomenon that London is famous for
• Atmospheric driving hazard
• __ machine