Arizona Faces Hazardous Travel as Dense Fog Advisory Brings Quarter-Mile Visibility Across Northwestern Parts of the State

ARIZONA — A Dense Fog Advisory is in effect through 9 a.m. MST Saturday for northwestern Arizona, where motorists are encountering dangerously low visibility, in some cases dropping to one-quarter mile or less, according to the latest weather data and transportation imagery.

Satellite and ground observations show thick fog settling along major desert corridors, particularly near AZ-66 and I-40, where visibility has rapidly deteriorated overnight. Images from traffic cameras near Armour Avenue and I-40 illustrate just how limited sightlines have become, with traffic signals and headlights barely visible through the fog.

What’s Causing the Dense Fog

The fog is being driven by a combination of overnight cooling, residual moisture, and calm surface winds, allowing low-level moisture to condense and spread across valleys and roadways. These conditions are common in the region during winter but can become especially hazardous when they persist into the early-morning travel window.

Meteorologists warn that fog coverage may vary sharply over short distances, meaning drivers can go from clear conditions to near-zero visibility within minutes.

Travel Impacts and Safety Concerns

The greatest concern is for early-morning drivers, truckers, and holiday travelers moving through rural highways and desert passes. With visibility reduced to a quarter mile in places:

• Stopping distances increase significantly
• Rear-end collisions become more likely
• Navigation through intersections and exits becomes difficult

Transportation officials are urging drivers to slow down, use low-beam headlights, and increase following distance until conditions improve later in the morning.

When Conditions Will Improve

Forecast guidance suggests fog will gradually lift after sunrise as temperatures rise and mixing improves. Most areas should see noticeable visibility improvement by mid-morning, though isolated pockets of fog could linger slightly longer in low-lying desert areas.

What Drivers Should Do Now

If you’re traveling in northwestern Arizona this morning:

• Avoid unnecessary travel until fog dissipates
• Allow extra time for commutes
• Stay alert for sudden drops in visibility
• Watch for slower traffic and unexpected stops

Dense fog may not grab headlines like major storms, but it remains one of the most dangerous weather hazards for drivers. Conditions will improve later today, but until then, caution is essential on Arizona’s highways.