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Mad River Blog

Friday, April 30, 2021

Winter 2020-2021 review - What could have been !

 The 2020-2021 ski season was certainly compromised as a result of the ongoing Covid19 pandemic but we still had one at Mad River Glen and we thank the efforts of all staff members that helped make that possible. On the weather side of things it was interesting because it almost always is.. We had two big east coast storms, a historic and very damaging cold wave in Texas and a persistently negative Arctic Oscillation yet in the case of northern Vermont, I can best summarize using 4 words. What could have been ! 

As expected, the winter was dominated by a moderate La Nina. It strengthened very quickly in autumn but SST's in key regions of the equatorial Pacific leveled off at about 1C above average and then began to fade late in the winter. Also as expected, the sea surface temperature configuration in the Pacific did create a weather pattern that was dominated by a strong Pacific jet stream which proved to be a mostly invariable force throughout the winter. The more dramatic and less expected distinction relates to the aforementioned Arctic Oscillation. Recall that the winter 2019-2020 was dominated by a very positive AO, one of the strongest recorded in the last 75 years, averaging an index over+2 over a 4 month period beginning in December and ending in March. Over the same period 2020-21, we saw an average AO of -.82 and the very positive AO we saw just recently in March blunted what would have been an even stronger negative number. More than anything else, it was the negative AO which helped daytime temperatures in the MRV average 2 degrees colder during the recent ski season than the season prior. This is not an insignificant figure over a 4 month period and really should have resulted in more snow across the Vermont high country. The stake at Mt Mansfield doesn't lie however. The snow season started below average and never caught up and quite honestly, I chalk it up to whole lot of bad luck. It simply should have been better given the selection of ingredients available to us. I'll expand on this point more when we review what happened in February. 

November of 2020 bore no resemblance whatsoever to what we saw during Snowvember 2018 or even last year. We started mild, we finished mild and the minimal snow we saw in between melted by the start of December. There was almost no support for early season winter weather in November across New England but the AO made the critical turn early in December and this began a long period of time where high latitude blocking effectively suppressed surges of more intense milder temperatures (with one exception). Interestingly, the blocking was largely confined to an area that included Greenland, the Davis Strait, the Labrador Sea and portions of the Hudson Bay. Having such a large block in relative close global proximity to New England actually prevented eastern significant amounts of Arctic cold from impacting eastern North America; nonetheless, it was enough to finally bring a stretch of sub-freezing temperatures to the northern Vermont high country beginning around December 5. The coldest stretch of days occurred in the middle of the month out in advance of what was the first of two major winter storms for New York and New England. Initially forecasts kept the storm south of Vermont but hopes were kept alive by the "northward shift" possibility, which specifically refers to a medium range model bias that overly limits the impact of nor'easters on interior New England. The bias is real and it happened again, as forecasts began shifting the track of the storm northward and higher resolution models began pinpointing the presence of a massive pivoting band of snow within the storm near the Vermont/ Mass border. Man, did we get close ! The MRV missed what could have been some historic snow by maybe 50 or so miles. In Vermont, the band concentrated in a line from near Granville east to Windsor, Vermont and produced as much as 50 inches of snow with high amounts recorded even in areas that often get screwed because of unfavorable oragraphy. It was frustrating to miss on some terrific early season powder by very little but it foreshadowed much of what became some very bad luck in northern Vermont that plagued us throughout the season. The storm did showcase the material improvements in higher resolution modeling, specifically how forecast data was able to indicate the presence of the pivoting heavy snow band. Ski areas such as Magic Mountain and Okemo certainly got a chance to bask in the glory of this storm for several days. Further north, we managed to build a 6-10 inch that seemed to accompany a growing sense of doom as the forecast for Xmas deteriorated. 

Christmas was indeed a disaster but guess who had it on the bingo card back in October when Vermont Ski and Ride came calling for an outlook ! I got extremely scientific with this prognostication going with the theory that 2020 was full of piss and vinegar so why should Christmas be any different. The storm was absolutely a freakish occurrence given the weather pattern by getting caught in the jet stream blocking in eastern Canada rather than tunnelling underneath as most storms do in those circumstances. It was windy, it was mild and our snow was all but gone by December 26th. It was a terrible but fitting way to end a not so great kind of year. 

The start of 2021 brought almost instantaneous improvement to Mad River Glen. High latitude blocking in the jet stream finally began to score some victories with the first coming from a very garden variety storm that moved from the lower Mississippi Valley to southern New England late on New Years Day. Steady snow fell across much of Vermont and much of ski country in the northern part of the state scored 6-12 inches. Much of what fell ended up staying on the ground through early March thanks largely to the persistently negative Arctic Oscillation. Interestingly, however, eastern North American remained largely devoid of intense arctic chill as the plethora of high latitude blocking structures, were, for a time, closing pathways for polar air to move from the Eurasian Continent. That would eventually change but for much of January, Vermont manage to experience a very impressive streak of sub-freezing temperatures that were, at the same time, above normal. Following the early month snow, a stretch of dry weather persisted for over a week and temperatures remained rather comfortable, staying mostly in the 20's and low 30's and never really falling below zero. We began to see signs of a storm for the MLK holiday but with the cold weather holding a very tenuous grip on New England and the Christmas fiasco still fresh in my mind, I will admit some apprehension. It ultimately looked apparent that the storm would not follow the same fate as the one on Christmas Day. The initial storm occluded over in Iowa and the main precipitation producing storm reformed over New York City early Saturday. Though the snow consistency wasn't optimal everywhere, the storm was the best event of the season with over a foot falling across the high country surrounding the MRV. Colder weather in the ensuing week along with several small accumulating snow events made for some terrific conditions and that persisted through the rest of the month even though the MLK storm was the last to impact the state for the remainder of the month. As for the arctic cold, it finally showed up in New England on the last few days of January with temperatures dropping to as low as -20 in spots on Saturday January 31st. 

February 2021 is a month that will be long-remembered and not necessarily for the right reasons in some parts of the country. For the ski areas in northern Vermont, I consider the outcome quite unfortunate since the chess board appeared set up for an absolutely glorious stretch of winter and the results were rather ordinary at best with our rain-less, thaw-less streak ending late in the month. The 2nd of the the season's 2 big nor'easters struck on February 1st and 2nd as a classic Miller B type event with a Midwest storm transitioning its energy and moisture to what would become a much stronger coastal system. Indeed it was very strong storm and proved to be an epic event for the NYC metro with upwards of 2 feet falling in some suburbs. Snow did reach most of northern Vermont but accumulations were very garden variety and fell short of even some modest expectations. The snow that did fall was nonetheless a welcome addition to a 5-week stretch of sub-freezing, rain/ice-free weather and the week that followed was a productive one with small accumulations of snow making the first full weekend of the month, one of the best of the season. It was a point in the season where everything looked as if it was going to come up roses as the Pacific jet appeared to be finally relaxing allowing the persistent blocking at high latitudes to win the day and the month. What was even more encouraging was the continued presence of a La Nina-style southeast ridge; which, appeared ready to steer multiple storms in our direction as oppose to a confining the impact to coastal areas. Normally, I would embrace this setup and do so enthusiastically fully expecting epic results. 

The weakening Pacific jet was as an absolutely critical occurrence and indeed allowed the blocking at high latitudes to produce an highly amplified pattern capable of producing a cold wave of historic proportions across the Texas, Oklahoma other parts of the middle of the country. Arctic air began its southward advance around February 7th, initially affecting northern latitudes including Vermont. By the weekend of Valentines Day however, the pattern would become even more amplified allowing very extreme cold to make a full on assault on portions of the Gulf Coast. As the cold continued to look more intense in Texas, it was gradually appearing less intense across New England and expectations began to shift from bone-chilling cold to a more defensive posture of fending off surges of milder air. The third week of February, you know the one that includes the holiday looked like a could be a 2-storm type of week and ended up being a wide-left and a wide right form if ugliness. The first storm late Monday into Tuesday involved a big push of mild air and had lots of moisture but an initial, decent burst of snow turned to sleet and ice. The 2nd on Thursday, Feb 18th, made a southward shift in the days leading up to the event and resulted in little to no snow in northern Vermont. The month ended with a muted thaw but and it was a microcosm of a month that should've been better. 

And while Vermont was glazing over with ice or getting bested by coastal cities on snow, Texas was freezing in darkness. The cold wave sent temperatures to -14 in Oklahoma City which is about as cold as the MRV got all winter. Readings were below zero as far south as Dallas/Ft Worth and a low as 10 degrees in some outlying suburbs of the Houston Metro. The intensity and duration of the cold wave stretched an already flawed electricity market in Texas, overseen by ERCOT (Electric Reliability Council of Texas) beyond its breaking point. Much has been written and politicized about a weather event that proved more impactful than multiple high category  hurricanes making landfall at once.  Though I don't operate within the ERCOT sphere, the power markets remain part of my home turf and it was disappointing to see misconceptions made by familiar characters in the aftermath of the event. The most common one involved laying the blame at the feet of renewable sources of energy such as wind which supply Texas with a critical amount of electricity throughout the year. Texas, in fact, leads the nation in wind generation, a source of electricity that many cold weather climates rely on in high demand periods and do so successfully. The Texas market however does not operate with the necessary incentives to seamlessly operate during high load events and especially during historic cold waves. When the postmortem assessments are completed, they will almost assuredly show how dangerously vulnerable the grid was to a historic cold wave and that planning for such an event was very poor with a limited sample size of data used to make an adequate risk assessment. Texas, more than any other region, is susceptible to gas freeze offs which effectively shuts off vital supplies of  natural gas to power plants when they need it most. Wind, could have provided Texas with a critical backstop but ERCOT failed to provide generators with the proper incentives to winterize their wind generation which is commonly done for wind generators farther north. ERCOT also operates with a reserve margin that is considerably lower, often less than 10 percent during high demand periods, than our market (NEPOOL) in New England which is typically closer to 30 percent. A  less than 10 percent reserve margin in a region of the country that can experience very volatile weather and energy demand is not a market structure that ensures reliability and is instead hoping for a combination of luck (which always runs out) and market forces (which have a funny habit of conspiring against John Q Consumer at the worst time) to operate successfully.  Don't let anyone tell you differently, the situation in Texas in February was a miserable embarrassment for free-market advocates who can wax poetic about how all of this serves the consumer. It serves no one to freeze in the dark, which millions did for a span of several days.

The milder turn the weather pattern took in late February continued into March. The AO which helped power the widespread cold outbreak in February abruptly turned positive in late February and stayed positive through March and when combined with a still active Pacific Ocean jet stream helped make for a rather torchy and surprisingly dry month. That said, winter tried to make a last stand in New England and Vermont was one of a select few states to see a sustained stretch of winter early in the month including a day, on March 2nd where temperatures struggled into the teens. Fittingly however, Vermont saw a very limited amount of snow when it was cold. The high country did see a few decent snow squall events but at no time do we see snow from an organized weather system. Ski country did see some excellent weather for spring skiing however. By my count, the MRV got to experience 7 days of near 60-degree, sunshiney weather which is unusual for us and gave skiers several days of healthy spring conditions. Too much of a good thing can present a problem for MRG lift service however and all of that warmth ended the official season on April 3rd. 

April followed with more surprisingly pleasant spring weather in Vermont but this was rudely interrupted on April 15 by an elevation snow event which brought some heavy snow to the same portions of central and southern Vermont that seemed to get much of the best snow all winter. Another even colder event on April 21/22 brought snow to the northern Vermont high country and helped make April a snowier month than March in spite of a lot of warm weather. 

Years ago, a very experienced and seasoned forecaster shared with me his feelings about what was going to happen during the upcoming summer of 1999. He was a believer that the 11-year sunspot cycle could be correlated with the North American weather pattern. The 11 year sunspot cycle refers to the oscillating measure of observed solar activity where it takes 11 years to complete one full cycle. There are peaks and troughs of such activity with the most recent peak occurring around 2014 and a trough having occurred very recently. He never did actually sell me as to why and how the correlation exists but he pointed out how hot and dry summers have occurred in the same point of each cycle stretching back (at the time ) of 50 years. 1955, 1966, 1977, 1988 were all hot and dry with a high activity of tropical cyclones. The forecaster nailed the 1999 summer forecast and though I never was completely sold on the sunspot link, the verification stuck with me and I remembered it going into the summer of 2010. Once again it was hot and dry. So, if you made it this far in the review and in the paragraph, you can probably see where I am going with this. 

I won't sell folks on the idea that the sunspot cycle is a predictor of a prevailing weather pattern. I really don't know. I do believe however, as many of you know, that the weather pattern can provide tells as to future weather. I've watched many dry weather patterns in spring lead to hot and dry summers. We've had some precipitation in April and some more is on the way in the upcoming week but we've been running deficits for several months with the biggest occurring in March. Unless we get a wet May that cuts into the building precipitation deficits however, count me as someone that believes a very hot and dry summer is on the way. Yeah, this kind of thing is a little too anecdotal and might need a scientific infusion but I have a sentimental weakness for some of that stuff and it was a good way to end another season of blogging. 

Hope everyone made the best of the season under some trying circumstances. Hope everyone enjoys their summer and we will talk again late next fall !!