The science behind the smoke

Something seem a little different about the Hudson Valley sky over the past few days?

The burnt tinge in our September air — giving the sun an eerie blood orange glow — is a result of the West Coast wildfire smoke.

Congratulations, you can now tick “wildfire-infused sky” off your 2020 bingo card.

Tuesday’s sunrise | 📸 Jeff Stedner

If you watched the news recently, you would have almost certainly caught some coverage on the worst wildfire season on record across Oregon and California.

The extent of the fires means that significant amounts of particulate matter are being lofted up into the atmosphere and then tugged across the United States by storm systems that ride along the jet stream (narrow band of strong winds in the upper atmosphere).

Smoke from wildfires contains all sorts of stuff: carbon monoxide, carbon dioxide, organic compounds, hydrocarbons, and nitrogen oxides. The particulate matter is on average about 2.5 micrometers in diameter, so much smaller than a grain of sand (62.5 micrometers) or human hair (100 micrometers).

For the Hudson Valley, the good news in this situation is that pretty much all of the smoke is elevated well above the ground — in fact, above 6000 ft. That means that the air we are breathing is wildfire smoke-free, a good thing for our respiratory systems.

Near surface smoke, 8:00 am Wednesday

All atmospheric smoke, 8:00 am Wednesday

Satellites, which constantly photograph the Earth from space, have captured the true color of the smoke from above. It’s best described as a haze or film. The defining features of our sky, like the sun, are forced to shine through it, giving a filtered appearance.

When will it go away?

Fortunately, we have the ability to model circulation patterns which can help accurately pinpoint the peak of smoke concentration and also when it will fade away.

The next 48 hours, through Friday morning, look pretty similar in terms of atmospheric smoke concentration. In other words, you can bet on some more interesting sunrises and sunsets.

Come Friday afternoon, a front will have passed through the Hudson Valley, allowing smoke free Canadian air to filter in from the north.

This will put a hiatus on the smoky skies, but they could return sometime next week.

5-day smoke animation: note how the coloring (smoke) fades away from the Northeast but heads toward Europe


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