Mystery Smoke on the M10 Lodge

[Lowell]

Driving northbound on the Lodge around 8PM on Friday, smoke began appearing after passing under the Hamilton Bridge.

At first I thought it would be some junker that had blown its rings and flipped on the air re-circulation. But by the time I reached the Davidson curve it was clearly more than that and was slowing traffic.

So I flipped on my iPhone video camera in its dashcam mount and shot this video.



The answer to its origin came at the Livernois exit where it smoke was pouring down into the ditch from an undetermined source and filling the expressway or miles.

But the puzzle remains. Why didn't the smoke go up? What is the physics answer to why the smoke would move DOWN and remain down for miles? Any clues?

[ypsifly]

Could be from the barometric pressure dropping and/or downdrafts. This happens when bad weather is approaching. If I'm in the woods and the smoke from my campfire starts coming down and swirling, I know its a sign that bad weather is on the way. The freeway was the lowest point so it just "stacked up" and swirled from the motion of traffic.

Wasn't that one of the days when we had pop up thunderstorms come through the area?

[jcole]

Could also have been a heat inversion; that's what causes LA and Denver to have those horrible days of yellow smog hanging in the air.

[compn]

yeah its the storm pressure . it also means you smell a lot more car exhausts even tho it can be breezy. the air cant escape.

[MikeM]

I'm trying to remember Friday. It stormed or rained on and off throughout the afternoon, right? By 8 PM the rain probably cooled the lower atmosphere creating a temperature inversion.

[Lowell]

Thanks all. That was my guess too. It had been rainy on and off all day and was still heavy and warm at 8PM. If just fascinated me that it would stay down so long. Also it appeared to be far denser on the northbound than the south lanes. The smoke tumblin down the Livernois exit was almost like a a waterfall.

[Jimaz]

They have bad problems with temperature inversions in Phoenix. It traps the smog while the sun cooks it into ozone which makes things like rubber and lungs hard and brittle. Nasty stuff.

I once hiked one of the urban mountains there and didn't realize how bad it was until I climbed above the inversion. Looking down, you can normally see the city below but not this time. It was completely opaque. All the mountains looked like islands emerging from a brown sea.

The Weather Channel recently ran a documentary about the 1948 Donora, Pennsylvania smog. It was attributed to U.S. Steel plants which refused to shut down during the incident. 20 humans and nearly 800 animals were killed.

[Ray1936]

We have an inversion in Las Vegas today causing smoke from the California "Powerhouse" wildfire to hang in our skies. Pretty murky out there today.

Southern Nevada rarely has any problem with wildfires because here in the Mojave desert plant growth is pretty sparse, but the westerly wind flow sure brings CA to us regularly.