Des Moines, IA – The National Weather Service (NWS) has issued a Dense Fog Advisory for western and northern Iowa, warning motorists to exercise extreme caution during the Thursday morning commute as visibility in some areas has dropped to less than a quarter mile.
The Weather Alert: Dense Fog Across Iowa
According to the NWS in Des Moines, fog began forming overnight Wednesday into early Thursday morning and is expected to linger until mid-morning, creating hazardous travel conditions.
Visibility has been reported at less than ¼ mile in multiple locations, including Denison, Fort Dodge, Mason City, and Spencer, with the thickest fog observed across north-central Iowa.
Meteorologists said the fog will gradually dissipate between 9 a.m. and 11 a.m. as temperatures rise and winds increase, improving travel conditions through late morning.
Travel Impact and Safety Concerns
Authorities have warned that dense fog can form rapidly, especially in low-lying areas, open fields, and near rivers or lakes. The limited visibility poses a serious risk for commuters during the morning rush hours.
“Motorists are urged to slow down, use low-beam headlights, and allow extra travel time,” the NWS said in its advisory.
Drivers are also advised not to use high beams, as the light reflects off the fog and further reduces visibility.
Highways most likely to be affected include:
- Interstate 35
- U.S. Highway 20
- Iowa Highway 9
- U.S. Highway 71
Areas Most Affected
Visibility maps from the National Weather Service show heaviest fog concentrations in north-central Iowa, especially around Mason City and Fort Dodge. Parts of western Iowa, including Denison and Carroll, are also under dense fog conditions early Thursday.
Officials said visibility could fluctuate quickly over short distances, meaning drivers may encounter sudden changes in visibility along their routes.
Precautionary Measures and Driving Tips
The Iowa Department of Transportation (DOT) has urged all drivers to remain alert and use the following safety tips when driving in foggy conditions:
- Reduce speed and maintain a greater distance between vehicles.
- Use fog lights or low beams only — high beams will reflect and cause glare.
- Avoid sudden stops and use turn signals well in advance.
- Follow road markings to stay in the correct lane.
- Pull over safely if visibility drops to near zero.
Ongoing Monitoring and Weather Outlook
Meteorologists expect fog conditions to lift by late morning, followed by clearing skies and mild temperatures later in the day. However, drivers are advised to remain cautious, as patchy fog may redevelop overnight in certain valleys or rural areas if winds calm again.
The NWS and Iowa DOT will continue to monitor visibility levels and update advisories as needed.
Residents are encouraged to check 511ia.org or local news outlets for real-time traffic and weather updates before heading out.
Conclusion
The Dense Fog Advisory serves as an important reminder of the dangers posed by limited visibility on the road. By slowing down, staying alert, and following safety guidance, drivers can help ensure safer travel across Iowa this morning.
Are you seeing dense fog conditions in your area? Share your experiences and updates in the comments below.
