Wednesday, January 10, 2018

The Warm of the Storm

Let's start with the good news.

If my math is right, storm total water equivalent at Alta-Collins through 7 am (9662 ft) is 1.20", producing 9" of base-building Cascade concrete.  Snow, possibly heavy at times, will continue through much of the morning.  The HRRR has things winding down late morning.  The NAM keeps a few snow showers around in the afternoon.  I'll go with another 2-5", mainly from 7 to 11 AM this morning.  We'll do a bit better than that if we can a good burst going or snow showers in the afternoon are more productive than expected.  These numbers are lower than the NWS Cottonwood Canyons forecast, but looking at the radar and the HRRR, I don't see us doing much better than that.  Even the "5" in 2-5 was a stretch.  Hope I'm wrong and they are right.

Now, let's shift to the bad news.

The prefrontal southwesterly flow was even warmer than I anticipated and temperatures overnight have cooled more slowly than expected.  A look at the temperature and precipitation graphs for Alta Collins shows temperatures hovering from 31-32ºF until yesterday evening and then only cooling very gradually to the current (7 am) value of 29ºF.

Thus, while we've added base builder in the upper elevations, the mid and lower elevation snowpack has taken a serious hit.  Further, the snow level remains high.  Even now, it is 34ºF at 8500 feet and the highest traffic camera in Big Cottonwood Canyon, which is near 7500 feet, shows only wet roads. 

I hate to say it, but get out and enjoy the high elevation snow today.   We may get a bit of windy "dirty ridge" snowshowers Thursday and Friday, but it won't add up to much.  Then the ridge returns.

Beggars can't be choosers.

Addendum @ 10 am

5 inches and .48" of water at Alta Collins since 7am.  Storm just exploded.  Wonderful! 


  1. It kind of feels like winter below 8,000ft is a thing of the past in the Wasatch.