Dense fog travel warning for Idaho and Oregon due to “dangerous” conditions

A blanket of thick fog has settled over the North West as December weather takes over the country.

The National Weather Service has issued a “Dense Fog Advisory” warning for much of Oregon and small parts of Idaho.

Air Stagnation Advisories were also issued in Oregon, Idaho and parts of Washington.

“Stagnant air conditions over portions of the Pacific Northwest are resulting in areas of dense fog and poor air quality,” the NWS said in a brief public discussion.

These atmospheric conditions can create “hazardous” conditions on the roads, which is why the NWS advises drivers to exercise caution.

What does a dense fog warning mean?

The NWS explains that a dense fog warning goes into effect “when extensive fog is expected to reduce visibility to 1/4 mile or less over a large area for an extended period of time (two or more hours) during.” There is air stagnation. An indication is given if “large accumulations of air pollution, smoke, dust or industrial gases are to be expected near the ground over a certain period of time”.

Dense fog warnings will continue until around 11 a.m. local time today, but air stagnation warnings will largely extend into Wednesday evening, while some will continue into Thursday or even Friday in some regions.

“When you drive, slow down and leave enough space in front of you. Pedestrians and cyclists should wear bright or reflective clothing to increase the likelihood of being seen by others in poor visibility conditions,” the NWS said in a statement.

They added: “Poor visibility could make driving conditions dangerous.”

Dense fog occurs when the air near the ground cools so much that its water vapor condenses into tiny liquid water droplets and a cloud forms on the surface. This requires high humidity, cool temperatures and little to no wind.

Additionally, “freezing fog” warnings have been issued in Nevada, Oregon and Northern California.

“Visibility less than half a mile in freezing fog, some dense freezing fog with visibility less than a quarter mile,” the NWS said in a statement.

“Low visibility could make driving conditions dangerous. The freezing fog can also lead to slick road conditions, particularly on bridges and overpasses.”

This foggy weather and air stagnation are caused by a high pressure system that prevents vertical mixing that would normally lead to the dispersal of pollutants.

These pollutants then accumulate in a limited area, causing air quality to deteriorate, which can affect people with respiratory problems and other health problems.

“An air stagnation warning indicates that due to limited movement of an air mass through the advisory area, pollution may rise to dangerous levels,” the NWS said in a statement.

These conditions can be dangerous for people with respiratory illnesses and can be made worse by nearby fires as the pollutants from the smoke are also trapped in the same area.

“State air quality officials strongly recommend against outdoor burning and limiting residential wood burning facilities as much as possible,” the NWS said.

“According to state air quality regulators, pollutants can be retained near the ground where people live and breathe for extended periods of time.”

Do you have a tip for a science story? Newsweek should cover? Do you have a question about fog? Let us know at [email protected].