J.Spin

I checked my CoCoRaHS numbers and found 50.46” of liquid for the 365-day period. That’s less than 10% below average, and seems very consistent with what the map shows for our area.

I was leaving my office, looked out toward the Greens, and was struck by what I saw. You’ve got clouds in the 3,500’ – 4,000’ elevation range skimming along the summits, and for the first time in a while, the clouds have some of that “cold season” look. I see temperatures in the 40s F and winds near 40 F as well, so that makes sense.

Everyone gets sick of excessive heat and humidity as they get older; I see them talking about it all the time in our main subforum threads. With age, it just gets harder to handle extremes like that.

For January snowfall days, the data show that last season was quite impressive among the data set. It’s interesting because both total snowfall (41.0”) and number of storms (12) were rather average this past January, but boy did it snow for “days and days and days”. January is a long month with 31 days, and to get snow on 29 of them is well above the mean as the plot shows. Recording snow on 29 days of a month is actually the highest I see in my records, so that’s another feather in the cap of winter 2020-2021, which generally felt like an “average at best” type of season.

The November data for days with snowfall definitely prompted some great discussion, and brought to light how good November 2018 was around here. Next up in the progression is December, and while this past December was certainly lean on total snowfall, the data show that it was solid with respect to days with snow. Overall, the plot suggest that December is actually quite the dependable month in terms of snowfall days, with 2/3 of the month delivering new snow on average. That means the wintry vibe should generally be there, which is appreciated by visitors as the ski and holiday seasons build. December definitely represents a bump up from November, where the average is just over 1/3 of the month for days with snowfall. …and then of course there’s good ol’ 2015-2016 that everyone talks about, sticking out like a sore thumb!

Now you’re getting it. That’s why you want to winter in a place where there’s always snow. Based on the yearly schedule Phin seems to be following, he definitely gets it. Most of us up here in NNE are here because of the snow, not because we have some strange obsession with wanting to freeze our azzes off. I did have to include that “most” qualifier though… because I’m sure they’re out there.

I was thinking back on this conversation where we were trying to figure out the annual snowfall average for your place at Jay Peak. I’d totally forgotten about the co-op there, since it’s been out of commission for so long. That co-op is literally a representation of your back yard, so I think we can thank Tamarack for getting you a hard number on your annual snowfall average. Our estimates were certainly decent though.

I’d forgotten about that Jay Peak co-op site, so thanks for bringing it up. I’ve always found that the data from that site simply reinforce the season snowfall totals from Jay Peak Resort. PF’s meticulous observations from Mt. Mansfield and the elevation-dependent snowfall discussion we’ve had at Liftlines and here are the perfect primers for people to make the connection. A 40% increase in snowfall at PF’s ~3,000’ plot over his ~1,500’ plot is certainly within reason based on the numbers he’s discussed. If you scale that 1,500’ ratio proportionally for the ~2,000’ elevation differential between the Jay Peak co-op and the Jay Peak summit, what do you get? …~350”. If you ask me, that’s suspiciously consistent with the ~355” season snowfall average that they often report for their summit elevation. PF literally states in the quote above that the 3,500’ – 4,000’ elevations are where you start to get into that “next level stuff”. But you know, since it doesn’t happen in everybody’s back yard, I’m sure nobody in the Eastern U.S., especially a greedy, profit-driven, slant-sticking, snowfall-inflating ski resort, can average that much snow in a season. The numbers must be cooked independently at both the co-op and the resort summit so that they line up perfectly. That’s how the conspiracy is run up there.

Yeah, I’d say bwt’s and PF’s comments here help clarify it, and Tony’s got those hard numbers on the last page of that Liftlines thread from 40 years of snow data that Mont Sutton gave him. The largest discrepancy in the numbers seemed to be due to the fact that Mont Sutton has traditionally been measuring snowfall at their base – and it’s a relatively low base at 1,300’. On top of that, if they were collecting in a walled, “box-style” container, that can have undercatch issues as well. So, from what I’m seeing in the provided data, the best numbers on Mont Sutton for annual snowfall are: 1,300’: 184” 2,500’: 238” 2,900’: 250” 3,900’: ???” I’m assuming that 2,500’ for the “mid mountain” elevation, since I saw PF using it, but I’m not sure what’s considered “mid mountain” there. The reason the final number in my list above is only question marks is simple: Mont Sutton just doesn’t go that high. So think about that elevation difference between Jay Peak and Mont Sutton - Jay Peak has another thousand feet of vertical on Mont Sutton, and most of us assume that Jay Peak is measuring their summit snowfall numbers somewhere in leeward spots up near that 3,900’ elevation. What would Mont Sutton be recording for annual snowfall up near 3,900’ if they had that extra thousand feet of vertical? Perhaps something near 300”? It’s hard to say though; the orientation of the mountain and the local topography can make huge differences in snow accumulations, and everything suggests that Jay Peak has some serious optimization in that regard. Also note, as much as the annual snowfall totals seem to increase like clockwork as you head from south to north in Vermont, it’s not as if annual snowfall totals simply keep increasing as one continues to head north of the border. The totals increase all the way up the Green Mountain Spine until you get to Jay Peak, and then they start to drop off as you head north into the resorts of the Eastern Townships. Right over the border you’ve got Mont Sutton that may get 250” at their summit, farther off to the east there’s Owl’s Head that reports 175”, and head another hour north to Mont Orford and they report just 140” for annual snowfall. I can also say from first hand evidence of skiing all three of those Eastern Townships areas in a single trip, that the actual snow conditions and snowpack played out exactly as those annual snowfall numbers would suggest. Mont Sutton was by far the best in terms of snow, Owl’s Head represented a substantial drop from there, and then Mont Orford’s snow was definitely the worst. Once you head north of the Northern Greens, the next segment of the Green Mountains is the Canadian Green Mountains (click the link to see the area highlighted at Peakbagger). Why does annual snowfall drop off so drastically as one continues north of the border in the Canadian Greens? There are probably a number of reasons, but elevations only top out around 3,000’ in that area as we see for Mont Sutton, so that’s probably a factor. The Canadian Greens could be a bit more removed from Atlantic moisture, they may lack as much access to Great Lakes moisture, perhaps their orientation and topography are not as good, etc. I’m sure that’s another fun topic for conversation. On a final note, as much as a 250” annual snowfall number for Mont Sutton may seem a bit weak compared to its neighbor Jay Peak, it should be pointed out that 250” is way up there on a regional scale. You’re not going to find an annual snowfall number like that anywhere in the Eastern U.S. outside of the Northern and Central Greens. I’d guess Balsams might be in that range if they were in operation, but Mont Sutton is the only one I can think of around here.

I think we’ve had a rather typical summer up here in terms of temperatures if you average it all out. I believe this current hot spell is the 3rd one we’ve seen? I know there was at least one or two early hot spells back in May or June. I’m not sure if we’ve actually hit 90 F at our place or not, but we certainly haven’t had one of those classic stretches of midsummer highs in the 90s F that heats up the swimming holes sufficiently. I’m sure we would have hit one of our favorite spots or at least gone river tubing if we did. It may have been a timing issue in that heat in May or June just isn’t quite going to do it because the water is still too cold, and then July was on the cooler/rainier side. You have me thinking though; this may be the stretch to finally get out for some river tubing, even if we’re not getting into the 90s. With at least relatively warm overnight lows, it helps keep water temperatures up. We’re into August now, and we’re even passing that magic August 10th barrier when it really gets hard to have sufficient heat for that most comfortable swimming. These next couple of days may be about the last chance for high summer feel as you noted, because even above average temperatures past this point of the season can’t quite do it.

Yeah, I recorded 10 winter storms that month, with 8.60” of liquid. My liquid records only go back to 2010, but that’s the wettest November I see in there. In terms of winter storm distribution, the first one was right at the start of the month, but accumulations were minimal from what I see. The real show started a third of the way into the month, so that means the remaining nine storms were packed into roughly 20 days. That’s a very respectable pace of storms even for a midwinter month. Following up on the PF nostalgia with some shots from the month - once we got to the 10th, the hits just kept on coming: November 10th November 11th November 17th November 18th November 21st November 24th November 27th November 29th

Yeah, that was a solid November. Even down here in the valley bottom, the data show it. For our site I see that November 2019 was actually tops in the number of storms with 12, but November 2018 still had 10 storms, 18 days with snowfall, and almost 35” of snow down here in the valley. We’ve really had a solid run of Novembers as of late, and the data clearly show it. It might come as bit of a shock when one of those weaker Novembers comes around.

The November snowfall and snowpack at our site can certainly give an idea of what the month is like with respect to snow in the Northern Greens, but of course, data specifically from the higher elevations of the mountains is going to be even better when it comes to thinking about ski conditions. With that in mind, the plot below has the snowpack depth from the Mt. Mansfield Stake at Thanksgiving for all the years that are available in that data set. I think that snowpack depth at that time of year does have some utility with respect to what you asked about (trying to get a better idea of what late November looks like in terms of skiing around here in the Northern Greens). For folks that just want to know if there’s going to be any skiing, I don’t think the natural snowpack depth is too helpful. Manmade snow is going to guarantee that there’s at least some skiing, for those resorts with the snowmaking firepower and desire to open terrain, at least 90-95% of the time. The natural snowpack depth is essentially irrelevant when it comes to that aspect of the early season. The natural snow depth is definitely helpful in getting a sense for how much extra terrain might be open beyond the usual early season snowmaking routes, how much natural terrain might be open, what backcountry options there might be, etc. From depth alone, especially a single point, it’s hard to get a sense for the ski conditions because you don’t know if that depth is what just fell and there’s zero base below it, or it’s just the slushy accumulation that’s hanging on because it’s warmed up after an earlier storm came through, etc. At a certain threshold of snowpack depth (I’ll just throw out 20 inches as an initial value for discussion), you start to hit a point where it won’t matter if the snow just fell, if it’s melting remnants from a previous storm, if it’s fresh snow atop an established base, or whatever. At some point, there’s going to be enough natural snow in place that resorts are going to open additional terrain. -If one uses the 20” snowpack depth threshold, that would suggest you’re looking at expanded skiing in about 20% of seasons. I bet if we checked reports from those seasons in the plot where natural snow depth was ≥20”, you’re looking at substantial additional terrain being open for Thanksgiving. -Just based on first impressions, I think that snowpack of ≥20” is a virtual slam dunk for additional terrain being open at the resorts, so a snowpack threshold of 16” is also worth a look. With that threshold, you’re looking at about 30% of seasons with expanded skiing at Thanksgiving. -The lowest threshold that I think might be practical (and this is definitely pushing it with respect to natural snow terrain being able to support lift-served levels of skiers) is probably around the 12” mark. You can certainly pull it off on well-maintained moderate or low-angle terrain if the snow is dense, but this is definitely going to be pushing it for lift-served. Some resorts are more liberal than others are when it comes to doing this sort of stuff. That would put the occurrence of expanded skiing at Thanksgiving at about 40% of seasons. That is unquestionably a higher percentage than reality based on my years of skiing around here, but we’ll just throw it out there as an upper limit. Jay Peak does have that bit of extra snowfall bump above Mt. Mansfield, so they may be the closest of any resort to that percentage, but it’s still definitely an overestimate. I’ve roughly estimated the 24” snowpack depth threshold at the Mt. Mansfield Stake as when people seem to start venturing into the most amenable off piste areas (trees). Experience tells me that the point where skiing well-maintained trails begins is definitely below that depth, but I’m not sure how low. I can certainly look at some reports from past seasons to try to get a sense for it. When it comes to getting out for ski touring on low-angle, well-maintained, on-piste terrain with fat skis; that can certainly be done on less than 12” of snow without concern for hitting the ground. You can do that on 10” of snow easily, or even 8” without even bottoming out if the snow is reasonably dense. The mean depth at the Mt. Mansfield Stake on Thanksgiving is 10.7”, which suggests that in the appropriate spots at elevation, one should have a chance to get out for some natural terrain touring on, or at least around (due to the temperature inconsistencies at that time of year) Thanksgiving in 50% of seasons. I wouldn’t be surprised to find that to be the case if I checked my records; it sounds very plausible.

I put together a plot of November snow progression for each season at our site. The plot and some periods of note: -As people in the thread have mentioned, that 2018-2019 season (bright pink line) is noteworthy with respect to November snowpack. Once the snow on the ground returned on the 12th of November, there was no going back, right through the end of the month. The skiing was simply going off in the mountains: -During November in the 2019-2020 season (green line), the snow wasn’t quite as deep as the year before, but it was quite persistent. There was just that one dip down to a trace on the 11th, but there was coverage from the 7th of month onward. And that was in the valley of course. It wasn’t as deep as some Novembers, but there was plenty of snow for touring at elevation: -November in the 2014-2015 season (yellow line) had a strong finish. There was some great natural snow out there, even starting well before Thanksgiving: -Last season (orange line) was unique with that impressive period of snow at the start of the month. No other season has anything like that so early in November at our site during my period of record. Accumulations were nothing extravagant at elevation, but it was definitely enough to get out for some touring:

I do have the snow depth data for Thanksgiving at our site, so I can start with that. More directly relevant for conditions on the slopes will be snow depth at the Mt. Mansfield Stake of course, so I’ll see if I can get those data together later. For now though, here’s the Thanksgiving snow depth at our site. The past couple of seasons have had typical snow depths, with an inch or two of coverage, but as folks have indicated, Thanksgiving 2018 was up there with the deeper seasons. I have plots of the progression of snow depth at our site over the course of the month of November as well, and that gives one a better sense of the monthly progression, so I’ll try to put that together next.

Looking at snowfall days for November, we can see that they were slightly above average this past season. Although we don’t seem to get huge storms in November, it certainly comes across as quite a wintry month in terms of days with snow. This is especially true over the past four seasons, where on average; half the days of the month have had snow.

OK, I found the discussion that dove heavily into the differences between base and summit snowfall numbers for the Northern Greens. It was actually over in the Liftlines Skiing & Snowboard Forums at First Tracks!! Online Ski Magazine. The discussion began because Jay Peak recorded the most snowfall of any mountain in the lower 48 states during the 2014-2015 season: https://skivermont.com/skivt-blog/2015/04/13/ski-vermont-receives-most-snow-in-continental-us-during-2014-15-season/ Actually, Jay’s reported snowfall was only 357” that season, but all of the Western U.S. outside of Alaska had a rather poor winter in terms of snow. Looking through Tony Crocker’s numbers for the 2014-2015 ski season, even snowfall heavyweights like Alta and Grand Targhee were just pushing a bit above the 300” mark. Alyeska still recorded 478” of snowfall at their 2,750’ plot though, so that area was probably tops overall in the U.S. The snowiest season I can recall at Jay Peak was 2000-2001 when they recorded 513”, and I believe that was the same situation. I think that number beat out all the resorts in the lower 48 states, but again not Alyeska, which recorded 638” at the 1,400’ elevation. For some reason, Tony has 581” listed for Jay Peak in his 2000-2001 Ski Season Summary, so I’m not sure if he had to extrapolate some sort of summit number from a mid-elevation number, but he has the 513” number on his 2000-2001 Ski Season Analysis Page. In either case, it wouldn’t top Alyeska’s number, so it would remain a similar situation to 2014-2015. https://en.wikipedia.org/wiki/Jay_Peak_Resort#Snowfall So, in terms of the base vs. summit snowfall differential, what came up in the First Tracks discussion were a couple of things. There was confusion about where Jay Peak actually records their “summit” snowfall numbers. It’s obviously not the actual summit of Jay Peak, since like Mt. Mansfield, that’s just a windswept area of rocks. The collection spot is likely in a protected, leeward spot (or spots) near summit elevation where the summit snow collects. It would be a spot like PF’s 3,000’ snow plot, or where the Mt. Mansfield Stake sits at 3,700’. Unfortunately, Jay Peak doesn’t have a PF like Stowe does, or even a measurement camera like Sugarbush and Stowe are starting to use, so their actual system of measurement is rather obscure. The second thing that came up in the discussion, and what also helped drive the discussion toward the details about base/summit snowfall differentials, was the snowfall at Mont Sutton, which is just a bit to the north of Jay Peak across the Canada-U.S. border. People (Tony initially broached the topic) were confused as to why the annual snowfall totals (200” at Sutton) simply seem to fall off a cliff as you head north of the border. The difference between reported snowfall at Jay and Sutton is so stark, that people thought Sutton might be reporting base area snowfall. Anyway, eventually PF made it to the conversation, and talked thoroughly about the cause of the snowfall differential between the upper and lower mountain areas in the Northern Greens. I’d already pointed out in the thread that the big differential is not due to an elevational rain/snow line, and PF came in to explain some very cool upslope stuff involving snow ratios, relative humidity, and mountain orographics that only someone like him would piece together. If you like the meteorology aspects of mountain weather, especially as it pertains to snowfall, definitely check out the thread (linked below) and PF’s contributions. In terms of rough upper mountain/lower mountain snowfall differential numbers, here’s a quote from PF in that discussion: “I've done the numbers before and regardless of the type of winter, the upper mountain plot (3,014ft) will receive somewhere between 30-40% more than the base at 1,550ft. It’s almost fail-proof. If the upper plot gets 300", the base will be around 200" or at least that's the general association.” I suspect PF will jump into this discussion at some point, so if people have questions or want to expand on that discussion at First Tracks, we can do it here. Here’s the link to that thread: https://www.firsttracksonline.com/boards/viewtopic.php?f=2&t=11837

I think I recall PF saying that more upslope actually enhances the difference in snowfall between base and summit elevations, due to the effect of the high ratio snow. We’ve got a discussion about it around somewhere, so I’ll see if I can find it. It’s hard to imagine the summit/base snowfall difference being greater at the SVT resorts though – with the relatively low snowfall numbers to begin with, they’d probably be looking at <100” of snow a season for the base areas, and that just doesn’t seem very practical. My quick recollection for Jay Peak would be that the annual snowfall at the base elevations is in the 200-250” range, but I’ll look around for the numbers we used in our discussions.

So as the plot above shows, I found that last season had the highest number of days with snowfall in our records. After looking at the data though, I see that it’s going to be able to claim another honor in that area: the winter of 2020-2021 was above average in snowfall days for all eight months of the snowfall season. Beyond being top of the heap for total days with new snow, the season also showed a remarkable level of consistency in that area. No other season in the data set even has seven months with an above average number of snowfall days; the next best performer managed to do it for six months. To get a better feel for how last season performed in terms of days with new snow, we can look at the individual months, starting with October as usual. This past October was actually quite typical for days with snowfall, but it did slip its way above the average:

Agreed, and that’s a good point - when one is using months for their intervals, they’re roughly equivalent spans of time, but not exactly the same. It would take a bit of work to get all the dates for days with snowfall from every season into the appropriate format to plot the distribution and find the actual midpoint for that parameter. While it might be interesting to know the midpoint of the season based on days with snowfall, a more practical measurement that I do have is the midpoint of the season based on cumulative snowfall. That point isn’t the middle of January, and it’s not the last day of January either – it January 25th (plot below). I wouldn’t be surprised if that’s pretty close to the midpoint that would be obtained from looking at snowfall days as well. With that date being the midpoint of the snowfall season for our location, we really shouldn’t get a single month serving as a symmetrical peak for the days with snowfall plot, and we also shouldn’t see January and February sharing the peak equally – the plot with those eight months would probably have its peak skewed a bit toward January.

Knowing the average number of days with snow at our site, I next looked at the monthly breakdown of days with snow. I actually had no idea how the data were going to distribute, but the appearance is certainly that of a unimodal distribution with a peak in January. It does look like there’s a bit of a skew of the peak to the left, but of course, we’re looking at a very coarse interval of months, and the eight months that happen to cover the snowfall season won’t necessarily correspond perfectly to Mother Nature’s actual snowfall season. We certainly have those years where it feels like January is relatively dry due to artic intrusions, so I could have easily seen some sort of bimodal distribution where January came in below December and February for days with snow, but that’s clearly not the case.

That’s good info, since as I mentioned, I don’t really have a sense for what numbers are like at sites around the region. Total snowfall numbers are always flying around, but days with snow isn’t talked about as much. I did the count for 0.5”+ from last season for my previous post, but I haven’t calculated all those thresholds yet. That’s an analysis I can certainly put on my “to do” list when I have time. I have it set up to run via COUNTIF in Excel, and with the CoCoRaHS data, it’s quick. There are of course a million different ways to analyze snow data (many that you and others here in the forum have shown me that I never would have thought about). What I find especially interesting about looking at the different parameters is discovering aspects of seasons that would never have been obvious. Who would have thought that the much-maligned, average-at-best 2020-2021 snow season would come out tops in our data set for days with snow? - not me. Nevertheless, that’s the type of interesting info that the analyses reveal.

The Northern Greens certainly seem to excel in the ability to put at least some flakes in the air throughout the winter. I haven’t really looked at that stat for other sites in the region or in the country, so I don’t know what’s typical, but 100+ days with snowfall certainly feels snowy. There are presumably sites in closer proximity to the lakes that get even more days with snow. I’d argue that many days with snow is a solid benefit when it comes to areas where winter tourism is important, since it at least improves the winter aesthetics for the visitors as you’ve noted. Thankfully, the flakes can be more than just window dressing and produce accumulations substantial enough to improve the surfaces on the slopes as well. If I check my data from last season for days with ≥½” of snow, which typically correlates with ≥1” of snow at the local resorts, that’s still 64 days. I should be able to do the monthly breakdown on days with snowfall, so we can look at that as well and see how last season stacked up. With 117 days of snow, it’s already up there at the top of the charts for the data set here, and I seem to recall we had a month this past season with just a couple of days where it didn’t snow.

That’s actually great timing on the inquiry LaGrange, days with snow was the next category I was planning to cover. Phin’s recollection is correct, based on the data I’ve collected so far, the average days with snowfall per season at our site is around 100. I didn’t track days with snowfall before joining CoCoRaHS, so I only have data from 2010 onward, but the plot is below. This past season didn’t have much to lay claim to since it was kind of lackluster in general snow stats, but days with snowfall was a category in which it edges out all the other seasons in the data set. Therefore, at least in our area, we had plenty of days with snow this past season, even if it was only average in terms of total snowfall.

Thinking about ways to get at which winter seasons had a tendency to deliver “larger snowstorms” vs. those that didn’t, I’ve made a couple of additional comparisons. Presenting the single largest storm as done in my initial plot above is certainly useful, but the single largest storm could easily be an outlier and not quite portray the tenor the season. Bringing a few more large storms from each season into the picture would temper the effect of those “one hit wonder” types of seasons. There are still plenty of options to consider with respect to how many storms to select, and whether to use mean and or median values from those storms, but here are two plots I made for now: 1) A clustered column plot that simply contains the snowfall for the five largest snowstorms from each season 2) A column plot that presents the sum of the snowfall from the five largest snowstorms from each season The first plot below is nice in that it lets one view the totals for the five largest storms of the season. It’s helpful for quickly identifying instances such as you mentioned above, where seasons had >1 storm of 20”+. I don’t think it works all that well for quickly getting at whether or not a season was one that tended to deliver large storms though. There’s enough data there in each set that they all just look like stair steps of data points unless you dive in and examine them closely. I think the second plot may do a better job of quickly highlighting those “big storm” seasons. Since each point is the sum of the top five storms, a season that consistently brings larger events is likely going to poke its head above the rest of the crowd. The 2016-2017 season is of course bolstered by the big 41” storm, but it’s still up there even when tempered by incorporating the next four storms. In this analysis, 2010-2011 and 2006-2007 also seem to pop up as potential “big storm” seasons. I like that 2006-2007 popped up on that plot, because it did have that “consistent, big storm feel” once it got going with what seemed like a notable storm on each holiday in the spring. Note that one could also plot the averages for the top five storms for each of these seasons and produce the same relative plot, but I think providing the number for total snow from the five storms gives a more immediate sense for the contribution that those top storms made to the season’s snowfall. While my initial plot of largest storm of the season certainly suggested that this past season was relatively weak with respect to large snowstorms, I think the plot summing the top five storms from each season solidifies that feel. This past season again came in as the second lowest in the data set next to the horrendous 2015-2016, suggesting that it was quite weak in the “big storm” department.