Mountain Highs, Valley Lows

I was going to wait and do this post tomorrow, but weather never sleeps and it seemed like a good idea to do it now.

Today was the first day I got up to the mountains during the current inversion.  The weather was as nice as you can get in December with blue bird skies, warm temperatures, and barely a whiff of wind.  

I never tire of the view of Mt. Superior

Balmy.  Temperatures as high as 43ºF were recorded at the top of the Collins chair today, but I suspect this was a bit higher than the free-air temperature as the winds were light and this often leads to overheating of the sensor when it is sunny. 

In addition, the ski conditions at Alta were fun too.  The groomers are grippy and carvable.  Fast is fun. 

Then came the dreaded descent into the Salt Lake Valley.  

And for comparison with the photos in the previous post, here's today's 4:30 PM shot from the Avenues.  

As discussed in that post, the buildup of pollution in this event is really quite remarkable.  Observations through 4 PM this afternoon suggest it is a virtual lock that we are going to exceed National Ambient Air Quality Standards (NAAQS) this afternoon (we sit at 34.3 ug/m3, but will surely climb through the 35 ug/m3 threshold in the next few hours).  That's right, from nearly pristine air for Santa's deliveries on Christmas Eve to a likely NAAQS violation 60 hours later.  

Source: Utah Division of Air Quality

I don't know what the fastest transition from clean air to a NAAQS violation is, but this may be one of the fastest in the past decade or two in Salt Lake City (perhaps someone out there can dig through the records).  This is a purely anecdotal observation, but it seems like in the past few years we have shifted into air pollution overdrive and the buildup of pollution is getting more rapid after cleansing frontal passages.  Welcome to Wasangeles.