I never thought I'd say this, but we need this to stop. We need the onslaught of storms to end, for the snowpack to settle, and for spring to begin.
Snowdepths and snowfall amounts right now are just ridiculous. Let's start at the Ben Lomond Peak SNOTEL, which is at an elevation of only 7688 ft (I'm not sure why it says 8000 ft in the figure below). Snowpack water equivalent at that site is now 78.7 inches, the highest on record, easily toping the 74.0" observed in 1984 (yes, 1984 at this site was higher than 1983).
A meteorologist friend of mine was wondering if this might be the highest snowpack water equivalent ever observed in Utah. I suspect that's likely. Perhaps someone out there can do some digging.
Down in the Cottonwoods, the Mill D North SNOTEL is now at 51.7", well above the prior 2011 record of 44.3". Records here, however, only go back to 1989 and don't cover those big early 1980s years.
Perhaps most relevant to what I want to talk about here is how steep the snowpack water equivalent has been rising at these and other sites. Mother Nature has added over 10" of water to the snowpack since March 15th. Snowbird has also added a bit over 10" of water since that time. Talk about load and stress!
Meanwhile, the Alta-Collins site picked up 19" of snow from 9 PM last night to 7 AM this morning, including a 6" increase from 1 to 1 AM. This is on top of the 14" that fell the previous night. Total snowfall for the season is now over
800 INCHES!
Insane. They are also well over 200 inches for the month. I'm not sure what the resort record is, but the Alta-Guard snowfall record for a month is 244.5" set in December 1983. We must be getting close to that.
All of this puts us deep into outlier territory. Readers of this blog know that I like to say beware when the atmosphere is in outlier mode. I woke up this morning, saw the huge snowfall numbers, and looked at the forecast and got a pit in my stomach. An incredibly deep snowpack. So much new snow. Slide paths that are greased.
And then I looked at the forecast and saw the GFS, after a break tomorrow, was forecasting over 3" of water and 40" of snow for Sunday through Tuesday.
Then I about threw up. The NAEFS mean is lower and around 2" of SWE, but still a significant event.
This must stop now. Both canyons are currently closed. The UDOT Cottonwood Canyons site reported that a natural bank sluff hit the road this morning. They are extending the estimated time of opening (ETO) now to 11 AM. The last I looked, there is no ETO for Little Cottonwood. Snow safety crews have been working the ragged edge all season, but especially over the last month. Avalanche threats exist not only in the Cottonwoods, but also along other highways where such slides are less common and only occur in big years.
And we haven't even talked about the runoff.
I am hoping we get through this cycle without incident and that after that we see a shift to something resembling spring with some longer breaks between storms. Both the GFS and the ECMWF are advertising a high-amplitude ridge to develop along the Pacific Coast by later next week and be parked there by 0000 UTC 10 April (6 PM MDT Sunday).
A lot of people have requested a blog post explaining what the hell has been going on this winter. Well here goes.
I don't know.
At least that's the tl;dr summary.
OK, I can do a little better than that, but explaining the whims of the atmosphere is very difficult and I don't want to suggest that I'm some sort of mystic who knows what is going on. I'm not sure anyone is.
Let's start in the fall. As usual, a variety of seasonal outlooks were issued by various groups. These always get a lot of attention, but their value is often limited.
I will use the official forecast issued by the National Weather Service Climate Prediction Center as example. Below is the three-month outlook issued in November for December through February. Due to the presence of La Nina (which has now waned), the forecast suggested that the dice were loaded for a dry southwest and a wet northwest. Utah could go either way.
Mother Nature, however, had different ideas, and for the mountain west, basically flipped that forecast on its head, producing a wet southwest and a dry northwest.
Mother Nature 1, NWS Forecasters 0.
To be fair, the forecasts issued by the Climate Prediction Center are probabilistic. They don't say that the southwest will be dry and the northwest wet. Instead, they forecast a shift in the likelihood of possible outcomes. Pure chance for any given winter gives a 33.3% chance of above, near median, or below median precipitation (in this case, median is broadly defined as a range around median). Equal chances, as was forecast for Utah, says there's no loading of the dice and they simply don't know what is going to happen. Below median, as was forecast for the southwest, indicates a shift to something like a 25% chance of above median, 35% of near median, and 40% of below median (the exact numbers vary somewhat regionally). Thus, the seasonal outlooks issued by the National Weather Service in November predicted a small shift from chance toward drier conditions in the southwest, although they are often interpreted or communicated in ways that make them seem more confident.
Long-lead-time forecasts, such as seasonal outlooks like the one above, are based largely on forecasts of more slowly varying components of the Earth's climate system that exhibit some predictability (over chance) at long lead times. For example, although the day-to-day weather cannot be reliably predicted after about two weeks, ocean temperatures in the tropical Pacific (e.g., La Niña or El Niño) exhibit some predictability at long lead times.
The outlook above was based largely on the presence and anticipated persistence of La Niña for this winter. Forecasts probabilities of above, near, or below median precipitation were based largely on what happened during past La Niña, with some consulting of computer models forecasts and expert judgment.
This sounds straightforward, but the the Earth is a complicated place. First, although we can anticipate La Niña with some skill, the forecasts aren't perfect or highly detailed. During La Niña the central and/or eastern tropical Pacific cools to below average, but the strength and coverage of the cold water varies. This in turn affects the distribution of thunderstorms and thunderstorm complexes in the tropical Pacific and in turn that affects the atmospheric circulation in different ways.
Then there is the inherent randomness of weather and weather systems. Waves and other flow patterns in the atmosphere can be highly chaotic. Think of a loose firehose. You can see there are waves in the hose, and they tend to exhibit preferred wavelengths and amplitudes, but there's also a lot of randomness. A firehose is relatively simple compared to the complex three-dimensional flows in the atmosphere where there are interactions between circulations near the surface and at upper levels and between the tropics, midlatitudes, and polar regions.
The existence of La Niña and other slowly varying characteristics of the Earth's surface (e.g., Arctic ice coverage, etc.) can affect some characteristics of the large-scale flow pattern, but there's still a lot of random stuff happening. How the atmosphere got the way it did during the 2022/23 winter is complicated, much like Harry Potter finding the sword of Godric Gryffindor.
With that in mind, let's look at the atmospheric circulation over the past few months. To do this we will use analyses of 500-mb height anomalies. The 500-mb level is often used to describe the upper-level flow pattern. Areas with positive height anomalies are places where there were anomalously high heights and ridging at upper levels. Areas with negative height anomalies are places where there were anomalously low heights and troughing at upper levels.
The 90-day height anomaly for October 4 to January 1 shows an anomalous tough over northeast Siberia (cool shading), a monster anomalous ridge over the North Pacific centered near the Aleutian Islands (warm shading), and a weak anomalous trough over the interior western US.
Source: psl.noaa.gov
For November 4 to February 1, the location and amplitude of these shift some, but the general pattern remains the same. Anomalous troughing remains over Siberia, ridging near the Aleutians, and troughing over the western US.
Source: psl.noaa.gov
And for December 2 to March 1, the story remains largely the same.
Source: psl.noaa.gov
And suppose we looked at the 30 day period ending in mid March (our current pattern still approximates this). Apologies for the color pattern change, but lo and behold, anomalous troughing over northeast Siberia (perhaps shifted a bit northward), ridging near the Aleutians, troughing over the western United States (and Canada).
Source: psl.noaa.gov
So, this general pattern of a trough over northeast Siberia, a ridge over the north Pacific, and a trough over the western US has been locked in for the better part of the winter. Overall, this pattern resembles something known as the negative phase of the Pacific-North American Pattern, or negative PNA, which is one of the leading patterns of atmospheric variability in the north Pacific and North America.
Scientists have created an index to measure the strength of the PNA pattern. Below is a graph illustrating 3-month averages of this index from 1950 through February 2023. The PNA index tends to flop fro positive to negative. This winter we have indeed been in a negative phase of the PNA pattern.
All of this is well and good, but it is where I am going to get off this train and here's why. First, the negative PNA pattern is associated with La Niña, so that makes some sense. However, La Niña weights the dice toward a drier southwest, which didn't happen this season. Something else is going on with the large-scale circulation and one index, like PNA, doesn't tell us enough. There's a lot happening in the Earth's climate system globally that might shift the PNA pattern characteristics or perhaps randomness played an important roll this season. People who are smarter than me and specialize in the large-scale circulation can perhaps answer these questions, but I can't.
As Tom Petty sang, "baby even the losers get lucky sometimes" and boy did we get lucky this winter.
March is winding down and what a run of cold storms we have had. How long they continue, I don't know but I was thinking that this spring has serious potential for a major corn harvest if the weather cooperates.
First, the snowpack is enormous and it is enormous on every aspect at at all elevations. We're not limping into spring as we have frequently over the past several years. The ability to follow the sun, work the softening snow on differing aspects, and to have relatively easy access to adventurous terrain could be as good as it gets this spring.
Second, we have had so much snow this month that any dust layers are buried deep in the snowpack and will take some time to emerge. Many years we have a dust emerging quickly in either March or April. An example below from 2018.
Thus, I am optimistic for the corn harvest, but the wildcard is the weather and perhaps the timing of strong south wind events with agricultural activities that disturb the land surface. It's helpful that it has been so wet this year, but lowland soils can desiccate quickly and agricultural fields can be huge emitters. We have seen examples of enormous dust emissions from tilled fields in the Cedar Valley in April (see Where Today's Dust Is Really Coming From (Not Sevier Lake) from April 2018). Such an event would sadly put a big dust layer on top of all this wonderful snow.
Let's hope for a great transition from powder to white corn, without any snirty dancing on dust until late in the spring.
I decided I could not miss out on this one-in-a-generation pattern and skied Friday, Saturday, and Sunday. My brain is basically whitewashed at this point. My waking hours have been in a snow globe. Friday and Sunday I toured. Saturday I racked up an enormous amount of lift-served vertical given my fragile back. I'm exhausted.
Thank God tomorrow is Monday.
Seasonal snowfall records have fallen at nearly all of the resorts. It's well known that this blog has an Alta bias, so we'll give them a hat tip for breaking their record since 1980.
In all likelihood, that's an all-timer, but we should probably wait for the Alta Guard reports to come in since records there go back to the 1940s (although the site hasn't always been in exactly the same location.
Also getting news is that the statewide average SNOTEL water equivalent is also at an all time high. This record has an asterisk. In particular, the sites used have changed from 59 sites in 1981 to 114 today. Thus, the elevations and spatial locations of new sites could have affected trends in the average.
It is also important to recognize that the statewide average being at an all-time high doesn't necessarily mean that every drainage is at an all time high. Snowbird, for example, is at a record high for the date (records begin in 1990), but is still more than 10 inches below its all time record.
So, let's be careful about thinking this year will be like the 1983 flooding down State Street because the statewide average is at a record. We certainly are concerned about the runoff, but much will depend on what happens over the next few weeks. Additionally, there have been important infrastructure upgrades since 1983.
Let's forget graphs for a while and look at some pictures. It's been a while since I've been above the S-curves in Big Cottonwood. What a scene! How about this snowbank at Spruces?
Bus anyone?
Good luck finding your cabin in Mill D after the next storm.
Someone shovel this roof before it collapses and makes a mess!
Meanwhile, on north aspects, I have friends that call this FM100 Easy Listening Skiing.
The snowpack is so deep that in some areas that it's up into the aspen canopy.
You know all that crap I say about Steenburgh winter and the low-angle sun before February 10th? It's so bloody cold that south aspects actually survived today. It got just a little stiff, but you can't feel that in the pictures.
Count your blessings that you are alive during the winter of 2022/23. I can't tell you how fortunate I feel to have lived to ski this season.
What an unbelievable season. It just keeps coming. McKenzie Skiles, a snow hydrologist here at the University of Utah, tweeted the photos below taken by Otto Lang of the Atwater snow study site above the Town of Alta. Multiple groups have instruments on the platform, including a profiling radar from my group (that's the dish). What a snowpack!
Snow has reached the platform at Atwater Study Plot in Alta, UT! Snow HydRO Lab grad students for height reference.
Snow HydRO Lab Phd Otto Lang grabbed this pic yesterday & it's still snowing hard! pic.twitter.com/QaDZhFTDlL
I attempted to ski tour this morning, but really, the snow was too deep for the hill we were on. The pictures looked good though.
Photo: Michael Wasserstein
It snowed hard for the entire 3500 vertical foot climb and I arrived at the top as a frozen wet sponge. I'm still shivering! It's late March and the snow was cold and in pretty good condition even at low elevations. Melt-freeze crusts? Perhaps buried, but not really an issue. Did I say it was late March? What a season.
We exited Mill Creek into the wall of snow associated with a strong snow squall. Visibility less than a quarter of a mile and rapidly deteriorating road condition.
Every day I look at the models and wonder when this will end. I don't know. Here's the latest downscaled NAEFS for Alta. A mean of more than 3" of water for the next week.
Do you ever wonder what it would be like if it started snowing and never stopped? - Steve Casimiro, Editor, Powder Magazine, 1987-1998
It's been a long week at the HAARP Weather Control Center. About a month ago, someone "discovered" that the Sierra-Wasatch snowstorm lever was locked at 11. Nobody knows who did it or when it happened, but it is jammed. They've tried shifting other levers to control the storm track over the past month, to no avail.
Weather and snow-depth sensors in the Wasatch are starting to disappear, like this one at Snowbird (photo from Sunday, 19 March).
The medium-range forecasts are clued in on this and continue to provide a parade of storms for the Wasatch Range. Last night Alta picked up another 7 inches, with their total snow depth hitting 190 inches at 6 AM this morning. The models continue to advertise more snow for today with the HRRR producing 1.27" of water and 15.4" of snow at Alta-Collins from 6 AM this morning to 9 AM tomorrow morning and the GFS 0.9" of water and 12" of snow.
Let's go with 12-18" and hope that comes through. No need to hope for more when the models are in the Goldilocks range.
Time for blogging has been limited this week. I've been quite occupied with the day job. If you see me on campus, treat me like one of this season's cornices and give me a wide berth. Grumpiness abounds.
