Wasatch Weather Weenies

In Wednesday's post, we mentioned the likelihood of unseasonably warm temperatures in the mountains this weekend (temperatures in valley and bench locations will also be mild, but how warm will depend on how stingy the valley cold pool is).  We are on track for that as the NAM continues to bring in +4˚C air at 700 mb (10,000 ft) for Saturday afternoon.  As I mentioned, I think this will cause a touch of spring fever. However, not far behind that warmth is a cold trough that will drop temperatures greatly by Monday.  The NAM forecast for Monday afternoon local time shows a deep trough over Utah with 700-mb temperatures around -14˚C over Salt Lake.    Looking at the numbers right from the model grid over Salt Lake shows 700-mb temperatures of 3.5˚C at 5 PM MST Saturday, 5.5˚C at 5 AM Sunday, -3.7˚C at 5 PM Sunday, -9.9˚C at 5 AM Monday, and -14.1˚C at 5 PM Monday. If that's not cold enough for you, the GFS is even colder and eventually drops the 70...

February arrives on Saturday and with it will be one of the warmest days we've seen in the mountains so far this winter. The GFS forecast for 2100 UTC (2 PM MST) Saturday shows high pressure in control, but a trough in the Pacific Northwest. Ahead of that slowly approaching system, 700 mb (10,000 ft) temperatures are forecast to be nearly +4˚C in the central Wasatch.  Balmy.  Such a temperature would not be a record for January or February and we once reached 5.8˚C on February 1st, but it is quite warm.  I suspect this will incite a weak case of spring fever as people enjoy the warmth and hopefully sun.  On the plus side, this is still Steenburgh winter, so the snow on upper-elevation north aspects should stay dry and continue to support good skiing. 

I haven't been blogging much about the forecast of late and maybe that's a good thing.  I keep looking at the models and thinking the next storm is sort of ho hum, and then it overproduces, resulting in a so-called sneaker storm. Last night provided yet another example.  SREF forecasts initialized at 0900 UTC 25 January (2 AM MST Saturday) produced anywhere from 3-12 inches with last night storm with a mean of about 8.  Thusfar, we're up to a 12 inch total, at the top of the ensemble range, and it's still snowing.  I could dig further, but who wants to jinx this run?  Let it keep coming. Shifting gears, it's now January 27th, which puts us nearly 2/3 of the way through meteorological winter (December-February) and the snow accumulation season.  In the Salt Lake Valley, it's been a relatively mild meteorological winter with a mean temperature at the Salt Lake City Airport through Jan 26 of 34.6˚F, the 16th warmest on record (i.e., since 1875)....

Yesterday (Saturday) provided some great cloud displays that help illustrate important atmospheric circulations. We'll start with the most "benign" —thermally forced cumulus clouds that formed on the mountains immediately north of Little Cottonwood Canyon yesterday morning.  These are a common site in Little Cottonwood and are the result of upslope flows that form over the canyon sidewalls.  It is likely that such flows form earliest in the morning on the south facing sidewall this time of year. In contrast, nocturnal downslope flows can linger later in the morning on the north facing sidewall.  The upslope flow helps to form cumulus clouds when the temperature and moisture profile is right. I also noticed some evidence of vertical wind shear and associated turbulence in the clouds near the Pfeifferhorn that morning, but nothing as dramatic or beautiful as what Luke Stone saw over Mount Timpanogos. Kelvin Helmholtz Waves above Mt. Timpanogos in American Fork ...

A hot climate topic in recent years has been the possible linkage between a warming arctic and midlatitude weather extremes, including severe winter weather.  An example of the types of headlines you've probably seen before is provided below from The Guardian .  Source: The Guardian This is a subject that has caused me a good deal of indigestion and that I've largely avoided in this blog.  This is because most of the evidence for this linkage has been based on observational studies, whereas model based studies have obtained differing results.   A new review article is now out in Nature Climate Change discussing the differing perspectives obtained form observational and modeling studies.  The paper is led by Judah Cohen and involbes a large number of authors including HongPing Gu and Simon Wang of Utah State University and the Utah Climate Center.   Source: Nature Climate Change Sadly, the paper is paywalled, but the National Scien...

Western Japan has one of the most remarkable and reliable snow climates on Earth, but as the saying goes, climate is what you expect and weather is what you get. During the East Asian Winter Monsoon, which over Japan features quasi-persistent northwesterly to northerly flow between the Siberian High and Aleutian Low, frequent cold-air outbreaks drive sea-effect storms near the Sea of Japan coasts of Honshu and Hokkaido Islands.  Mean annual snowfall exceeds 500 inches in some mountain areas, much of it falling from December to February.   This year, however, the winter monsoon has been more of a winter "nonsoon."  Snow depth observations as of today, 22 January, show many sites with under 50 cm of snow and only four over 100 cm (about 40 inches).   Snow depth observations in cm.  Source:  http://www.data.jma.go.jp/obd/stats/data/mdrr/snc_rct/index_snc.html . This is unusual as nearly all sites are well below average, especially on H...

This Thursday Evening's Frontiers of Science Lecture is one you don't want to miss.  Dr. Craig Clements, Professor and Director of the Fire Weather Research Laboratory at San José State University will be speaking on Advances in Observing the Wildfire Environment: Understanding the Role of Fire-Atmosphere Interactions .  The talk is scheduled for 6 PM in 220 ASB (Aline W. Skaggs Biology Building).  Free parking is available in the Chemistry Lots.  Complete information is available at  https://science.utah.edu/news/frontiers-of-science/ . Craig is a University of Utah alum and the "Indiana Jones" of wildfires.  You've probably heard of tornado storm chasing.  Well, Craig is an extreme wildfire chaser, using scanning Doppler lidars and other instruments to better understand how fire-atmosphere interactions yield extreme fire behavior.  Craig is a great and engaging speaker.  This is definitely a lecture you don't want to miss. 

One of the "worst" days I've had this year.  Photo: Erik Steenburgh. It's been a pretty good ski season thus far and, thinking like Gordon Gecko, I think our motto going forward should be "Greed Is Good."   NRCS SNOTEL data as of 18 January shows that most northern Utah observing sites are at or above median.  In the Wasatch Range, only Timpanogos Divide (93% of median) and Cascade Mountain (82%) are below median.   Source:NRCS The Snowbird SNOTEL has both the highest water equivalent (23.8") and percentage above median  (143%) in the Wasatch Range.  A look at this water year's trace (blue line below) compared to water years since 2011 shows we are running well above all water years except 2019 and 2011 (year denotes the last year of the water year — i.e., 2019 = 2018/19).  Further, we were ahead of 2019 during much of December and are only a little behind, so the difference is negligible.   Source: CBRFC The ...

There are places in the Wasatch that make me think of Mount Crumpit from Dr. Seuss' How the Grinch Stole Christmas.  Whoville in this case is, however, not a small town. My favorite passage from Dave Hanscom and Alexis Kelner's essential guidebook  Wasatch Tours: The Northern Wasatch  describes the route up Mount Crumpit as follows. "No ski area developers have cleared the willows and oak, so considerable ingenuity and determination are required to get through the brush.  True cross country touring is, after all, a character developing and strengthening form of recreation."   Yup, it's not easy.  However, the Grinch favors the route below, which was skied by some of his assistants prior to our arrival. And one need look no farther than Dr. Seuss for inspiration for your next mountain adventure. "You're off to Great Places! Today is your day! Your mountain is waiting, So...get on your way!" -Dr. Seuss, Oh, the Places You'll Go...

Our latest storm cycle certainly ended with a bang this morning.  Observations from Alta-Collins show a total of 16 inches as of 3 PM, but 10 inches fell in the 4 hours and 6 inches in 2 hours ending at 8 AM.  Storm winds were also strong.  With a peak ridge-top wind gust at 11,000 ft of 80 mph around 9 AM.  The heavy snowfall and perhaps wind transport led to some natural avalanche activity in the Y and Y-Not Couloirs on the south side of Little Cottonwood Canyon.   Video avalanche in Y and Y-Not Couloirs in Little Cottonwood Canyon which has seen intense snowfall. #utavy @UDOTavy @UDOTcottonwoods pic.twitter.com/rRE3uX3fRy — UtahAvalancheCenter (@UACwasatch) January 17, 2020 Strong winds were also observed at mid-elevations, even in some tree-protected areas.  Having returned from Boston after a long work trip, I headed out this morning and found it necessary to stay layered up even on the long climb.  The MLK weekend ...

I've been unable to prepare a blog post in a few days, so it's time to catch up on several subjects. AMS 100 I've been away from Utah for several days attending the Annual Meeting of the American Meteorological Society (AMS).  It is a noteworthy meeting as it is the 100th anniversary of the AMS.  When the AMS began, routine upper-air observations did not exist and the concepts of upper-level waves and the jet stream weren't developed.  Digital computers hadn't even been invented.  Radar wasn't invented.  Wireless radio communication was in its infancy.  Today, we observe the atmosphere from space, surface observations are ubiquitous and shared instantaneously, we get near instantaneous information about storms using radars, and some of the world's biggest computers are dedicated to weather prediction.  It is clear that meteorology has made incredible progress over the last century and that we should be excited about the next 100 years. Alta 100 a...

The snow continues to pile up and the automated snow depth sensor at Alta Collins reached 96 inches at 6 AM this morning. This puts us on the cusp of Steenburgh winter , my vain name for the crème de la crème of backcountry ski conditions when the snowpack is deep and the sun angle low.  Officially, Steenburgh winter extends from the day when the Alta-Collins snow depth reaches 100 inches to February 10 when the sun begins to have an increasingly caustic influence on the snow as spring approaches.  We haven't had many Steenburgh winters in recent years.  A quick look shows that seasons with Steenburgh winter conditions since I began this blog in 2010 are: 2010/11, 2016/17 (barely - we hit 1000 inches on Feb 10),  and 2018/19.  It could get close, but I don't think we will reach the start of Steenburgh winter today.  We need another four inches and things seem to be winding down as I write this.  Our next storm, which looks to be a good one, de...

Sad news from Idaho where 2 skiers were killed in an avalanche at Silver Mountain.  Media reports indicate that the avalanche occurred in in-bounds terrain that had been open for less than an hour (see this article from The Spokesman-Review ).  This is an unfortunate reminder that mitigation efforts reduce avalanche hazard at ski resorts, they do not completely eliminate it.  As discussed in my book Secrets of the Greatest Snow on Earth , on average slightly less than one avalanche fatality occurs per year in in-bounds terrain that has been opened by ski patrol at US ski areas.  Although this is much lower than the number of deaths in backcountry areas, it is not zero.  Avalanche mitigation and hazard assessment is inexact.  It is a human endeavor in an environment in which there is not complete knowledge.  That being said, there is little doubt that snow-safety teams do great work.  Just check out the photo below of Alta after it was raked by...

The pattern over the next 7-10 days looks pretty good for Wasatch snow lovers as several weak systems move through the region. Ten-day total accumulated precipitation from the ECMWF model (top image below) indicates roughly 1-2 inches of water equivalent in the central and northern Wasatch, while the GFS generates greater amounts.  Such results are fairly consistent with model biases as the GFS tends to be wetter than the ECMWF. Source: Pivotal Weather Source: Pivotal Weather Our downscaled NAEFS product for Alta over the next seven days (i.e., through 0000 UTC 14 January) shows that after dry weather prevails today, a progression of weak systems through the area.  There are no huge one-day dumps if the GEFS members, but instead a series of systems that slowly but surely add up to a mean of just over 2 inches of water equivalent and 35 inches of snow.  Some Canadian members are more inclined to produce heavier snowfalls.  That's not out of the realm o...

Three years ago I was in Japan on a trip that involved some skiing and collaborative work with scientists at the Nagaoka Snow and Ice Research Center (SIRC).  Joining me for the trip was University of Utah graduate student Peter Veals.  Exactly three years ago today we were ski touring in the Hida Mountains, also known as the northern Japanese Alps.  Hokkaido gets a great deal of press, but the Hida Mountains on Honshu offer up some of Japan's highest terrain.  Whoever said Japan is deep not steep has never been to the Hida Mountains.  The tricky part in the Hida Mountains is having a day with stable snow and good visibility, and we were fortunate to have one.  It is possible to purchase a single ride ticket at Happo Ono or Tsugaike ski areas to begin your tour in the alpine.  Given the relief of the Hakuba Valley, I suspect this is greatly preferred by most ski tourers when the alpine is accessible, although you won't be alone as many opt to do...

It was a pretty good day for cloud viewing today.  First, there was a brief display of altocumulus undulatus at Alta.  Such cloud billows were likely produced by a phenomenon known as Kelvin-Helmhotz (KH) instability, which occurs when strong vertical wind shear leads to atmospheric overturning.  Source:  https://www.eoas.ubc.ca/courses/atsc113/flying/met_concepts/01-met_concepts/01b-special-clouds/billow.html Then there was a beautiful sunset, with lenticular clouds hanging over the central Wasatch.   These stationary clouds were generated as the atmospheric flow was forced over the Wasatch Range.  Below is a web-cam video looking south from the University of Utah illustrating the stationary nature of the clouds (apologies if Blogger has coarsened the resolution, but my time is tight).  Finally, there's nothing too exciting about the altocumulus clouds below, but it was a pretty sunset over the Oquirrhs with a weak sun pillar,...

With the holiday's winding down, I think it is safe to say that we have been blessed with some outstanding skiing for December and the first couple of days of January.  Really, the entire month is a blur to me.  This morning, walking up the stairs to my office felt like climbing an 8000-meter peak (not that I know what that feels like), but I'm hoping to rally in time for a short skate ski later today. Snowpack water equivalent (i.e., the amount of water in the snowpack) is above median at most SNOTEL sites.  The few sites that are below median are barely below median.  In the central Wasatch, Snowbird, Brighton, Mill D North, and Thaynes Canyon are at 138%, 119%, 122%, and 110% of median.  In the northern Wasatch, Ben Lomond Trail and Ben Lomond Peak are at 127% and 117% of median.  Source: NRCS Snowbird and Ben Lomond Peak have the largest snowpack water equivalents with 16 and 15.1 inches, respectively.  I did some ski touring in the Ben Lom...