October Is a Great Bonus Month

October is my favorite "bonus" month.  Everything about the month is a bonus.  If it snows, the skiing is a bonus.  In Utah, if it doesn't snow, there's a good chance the weather is great for hiking or mountain biking.  The colors start to change and the views are wonderful.  Southern Utah is more tolerable.  It's hard to say anything negative about October.  

And today was the epitome of October.   Blue skies, mild temps, beautiful colors.  

The new BST from Mueller Park to Wild Rose is such a pleasure to ride this time of year.  Much of the trail was dense and moist.  Almost as if someone had oiled it.  Views were spectacular both up mountain

and down mountain.

Residents of Bountiful and North Salt Lake are fortunate to have such a great trail to ride.  I feel jealous whenever I go there given the unfinished trail plans in the Avenues.  

The colors this year seem especially vibrant.  I think this is one of the better falls for colors I've seen here in Utah.  What do others think?

Great Fall Weekend Ahead

We have a sublime WYSIWYG (What You See Is What You Get) forecast for this weekend.  Currently, parked under and upper-level ridge.

Tomorrow we're parked under an upper-level ridge.  

Sunday we're parked under an upper-level ridge.

You get the point.  "Severe clear" is the operating phrase.  Enjoy the fall colors.  

October Snow Is Here

October is coming in like a lion with thunderstorms late yesterday and more action overnight.  Dawn broke this morning with a light coating of snow at Alta.  I'm surprised nobody has put a skinner in yet. 

Source: Alta Ski Area

Looks like trace amounts at the base, but perhaps 2-3" up high, which may include a bit of snow from Saturday night.  It's unclear if the Collins snow-depth sensor is working yet, but the gauge came in with 0.38" of water equivalent in the last 24 hours. 

I mentioned in the previous post the possibility of snow, but was leaning toward a few inches and was inclined to have low expectations for the event.  The models, however, have been trending toward a wetter event.  The GFS, for example, is putting a low moving precipitation band directly over the central Wasatch today.  

It then brings a cold, moist secondary trough trough Utah tomorrow.  

Telescoping down to Little Cottonwood, the GFS generates a remarkable 1.75" of water at Alta-Collins from midnight last night through this afternoon, followed by dribs and drabs tomorrow with the trough passage.  It's a warm event, with the wet-bulb zero between 8000 and 9000 feet, but that would still mean snow levels around 8000 feet.   

The HRRR is coming in with somewhat similar numbers, but has a bit less precipitation for today.  

Snow totals for the HRRR are around 12" and for the GFS around 20" for Alta-Collins, which is at 9700 feet.  I suspect the snow-to-liquid ratios being produced by our algorithm are going to be too high for this event since it's not really designed for early season events with a warm ground and frequent excursions during dry periods to temperatures above 32°F.  

I'm inclined to lean toward 4-8" of wet snow from 8 AM to 6 PM for today at and above Alta–Collins.  The GFS is putting out some big numbers, but I think it may be generating a bit too much precipitation based on what I'm seeing on the radar this morning.  Things should quiet down tonight and then we will have to see what happens with the trailing cold trough.  

Fall Weather for the Weekend

I had a meeting yesterday at Snowbird and it didn't disappoint with lovely fall colors in Little Cottonwood Canyon.  

The concept of "peak color" in Utah has always been an odd one for me.  Unlike the northeast US where the elevation contrasts are smaller and the trees and shrubs seem to have a more consistent timing for the fall transition, there are fairly large variations with elevation and species here.  That said, I thought it was quite pretty throughout the canyon and especially enjoyed what I think were gamble oak that were on fire in places in the lower to mid canyon.  

The forecast for this weekend is also very fall like.  A deep upper-level trough is digging and amplifying just to our west today and tomorrow.  Saturday we will be ahead of the system in the warm southerly flow with temps near 80°F in the valley.  Expect some breezy conditions in the valley and in the mountains and high clouds at times.  

Then the wheels begin to fall as the trough progresses slowly eastward and colder, moist air bleeds in on Saturday night bringing some showers and possibly thunderstorms.  Sunday will be more than 20°F cooler with showers and possibly some thunderstorms at times.  

Just how much rain we get on Sunday will depend on factors I can't reliably anticipate at this time.  If we can get into the so-called "dry slot" associated with the low, it might not be too bad of a day.  On the other hand, we could also see considerable shower activity.  The downscaled SREF has some members with fairly light precipitation (less than 0.1" total, whereas others are wetter.  Of the latter, some are wetter Saturday night, others during the day Sunday.  

I'm going to do my leaf peeping on Saturday and then adjust plans depending on evolving forecasts and weather on Sunday.  

I'd be remiss if I didn't mention the possibility of some mountain snow Saturday night and Sunday and then through early next week as the coldest part of the trough moves through.  The latest GFS-derived forecast for Little Cottonwood shows the wet-bulb zero level dropping to as low as 8000 feet Sunday morning and then lingering around 9000-8000 feet through Wednesday (upper right panel below).  

The snow level is usually 500-1000 feet below this.  For Alta Collins, which is at 9700 feet or so, the GFS is putting out a total of almost 0.7" of water through Tuesday, which equates to perhaps 5 or 6 inches of snow.  The sometimes overoptimistic NAEFS ensemble has a few members eclipsing 15" but most are in the 5 to 12 inch range.

I'm inclined to knock those numbers down a bit, with a few inches on the highest peaks the most likely scenario.  If you are hoping for skiable snow, it would probably take the right flow and some lake-effect magic to kick in early next week as the trough slides eastward.  For example, the Euro puts us in cold northwesterly flow at 0000 UTC 4 October (6 PM MDT Tuesday).  

That's nice, but a lot would need to come together to give us a big dumpage.  I'm inclined to have low expectations for this event.  At this time, the odds we get enough snow for marginal ski touring in grassy areas are fairly low.  However, if you are desperate for hope, they are non zero. 

I'll also add that this appears to be a one-off trough with a return to dry fall in its wake.  We'd be better off if it didn't snow at all (yes, I know that is heresy). 

Another Year of Limited Bus Service

It was pretty disappointing to see yesterday that UTA will only be offering limited ski bus service again this season.  

To make more room for skiers and snowboarders on this year’s limited ski buses, UTA plans to provide alternative transportation for ski resort employees — “vanpools,” in vans loaned out to resorts and driven by resort workers.https://t.co/OibOhoFC6o

— The Salt Lake Tribune (@sltrib) September 26, 2023

Last year, even with the frequent closures of Little Cottonwood, Utah reported a record of 7.1 million skier visits.  On many days, parking lots were full.  Parking at trailheads was also tough to find.  What few buses were run were packed.  

We are still two years away from the so-called "phase 1" enhanced bus service for the Cottonwoods planned for fall 2025.  At that point, we are told that the roads will be tolled and there will be a mobility hub at the gravel pit, winter roadside parking restrictions, etc.  That will provide some much needed infrastructure upgrades, but one has to wonder if there is real commitment to providing serious bus service.  

In the interim, maybe it is time for slugging, or ad hoc casual car pooling, as is done in Washington DC, where drivers can pick up passengers (in this case skiers or snowboarders) at specified locations.  Call it ski slugging if you want.  I've always been surprised that we haven't seen more of it here.  

Is It Really Going to Snow?

Yes.

At upper elevations.

But not a lot.

Don't plan on skiing.  

The instigator is a cold upper-level trough that is dropping into eastern Oregon and Nevada today.  By 0000 UTC 22 September (6 PM MDT Thursday afternoon), the low center and the coldest air over southeast Oregon.  

During the day today, we will be seeing some periods of rain as the weak front ahead of this system pushes through.  The temperature this morning (0700 MDT) is 34°F, with a wet-bulb temperature of 31°F, so that's cold enough for snow on the highest peaks of the Wasatch.  Snow levels will lower later this morning and probably get to around 9000 feet this afternoon.  

The GFS is putting out about 0.35 inches of water for Alta Collins through Friday night, which given relatively low snow-to-liquid ratios equates to about 3.5 inches of snow.  Those snow-to-liquid ratios are probably higher than they should be as this time of year the ground is warm and there will be melting between snow periods as temperatures rebound when there isn't precipitation.  

The HRRR is less excited, and putting out 0.17" of water and 1.4" of snow.  Yawn.  

If you want more, you'll have to hope that the strong showers (there may even be some thunderstorms) setup in the right place to provide a strong and prolonged period or two of snow.  That's not impossible, but it's more likely that we see 1-4" of wet snow above 9000 feet, with the higher accumulations happening only if we can sustain snowfall rates for a while.  

It would be better to save this until early November, but Mother Nature does what she wants.