Wildfires that continue to burn in forests north of the border are once again having an impact on Minnesota's weather, but this time air quality isn't being as badly affected on the ground.
Smoke that drifted into Minnesota from fires in Saskatchewan in July was so thick it caused the air quality in the Twin Cities to reach dangerous levels – worse even than Beijing – prompting health warnings across the state.
The National Weather Service (NWS) said the weather here would be affected again Wednesday by wildfire smoke, and it's led to haze across parts of the state.
But air quality hasn't deteriorated to the levels seen last month, with the Minnesota Pollution Control Agency's index saying quality across the state is currently "good."
There was, however, a small spike at around 2 p.m. Wednesday where quantities of fine particles in the air around the Twin Cities were described as "moderate," which means it could have had adverse effects for those sensitive to air pollution.
The reason the NWS said it wasn't as bad as last month is that the smoke has stayed higher up in the atmosphere, rather than in July when it hung closer to the ground.
Treehugger explains why smoke-related haze leads to some spectacular sunsets: The size of smoke particles from the fires filters out certain colors of the spectrum while letting others through – namely red, pink and orange.