It's been a while since we've had an airmass push into Utah from the northwest, but it happened last night and it brought the smoke from a distant fire, partially obscuring the Wasatch Mountains this morning.
The smoke is from fires in Oregon and possibly northern California.
The 2-day loop below shows the push of high pressure and northwesterly flow into Utah overnight.
And with the smoke came a bump in PM2.5 concentrations overnight, as if we don't get enough crappy air in the winter.
Source: Utah DAQ
It will be nice when those fires are out and the northwest returns to a source of pristine air!