It's deep. You could just smell the fresh air when you got within about 50 vertical feet of the ridge of the Avenues Foothills this evening. Most of the stuff over the Salt Lake Valley appeared to be thick "smaze" (smog and haze), with some low clouds in places, but a fairly solid deck of fog or stratus was evident over the Great Salt Lake. The cold pool was much stronger there. Note the lower temperatures (~40ºF) compared to over the Salt Lake Valley (43–48ºF).
The burn off of the fog at the Salt Lake Airport showed up real well in ceilometer observations. A ceilometer is a vertically pointing laser and receiver. Energy scattered back to the laser can be used to identify clouds, haze, etc. The image below shows a time series of vertical profiles from the ceilometer from 1253–1753 MST today with time increasing to the right (the y-axis is height above ground level in meters). The fog shows up as the red and maroon colors. It dissipates around 1420 MST, with the lingering lower returns produced by the "smaze."
|Source: MesoWest Ceilometer Network|