J.Spin

It’s cool to see that there are folks out there who like that type of snowfall regime, although I’d say it’s still quite a minority of the people I’ve seen on this weather forum. Most of the forum focuses on tracking big winter storms. That’s a huge part of the winter climatology for a lot of places outside the mountains or LES areas though. From the perspective of many skiers, a winter pattern with consistency is where it’s at. Yeah, larger storms are important for base building or getting in those bigger powder days, and they’re awesome when they come around, but it’s the daily snows that will really keep the snow quality up. To get by with generally good to great ski conditions in a feast or famine snowfall climate, there really needs to be great snow preservation, such as is found in the high elevation/dry air climates of some of the higher mountain ranges.

Yeah, we’re into the back side moisture that some of the models like the GFS have been showing for this system (Winter Storm Nathaniel) to potentially persist through Friday/Saturday. It was hard to know how it would play out because only some of the models were showing it, but it looks like it’s there on most global and mesoscale models now. Thus far it’s been fairly light here, with a tenth or two of new snowfall per six-hour block, but we did just get some steadier flakes that dropped another half inch fairly quickly. It’s certainly been keeping us with that classing NNE mountain regime of flakes in the air. As PF would say…

Event totals: 2.0” Snow/0.08” L.E. The snowfall has recently picked up this evening, and it may be associated with the echoes that have popped up on the radar, but the look is very localized over the Champlain Valley at the moment. Details from the 10:00 P.M. Waterbury observations: New Snow: 0.1 inches New Liquid: Trace Temperature: 24.6 F Sky: Light Snow (2-10 mm flakes) Snow at the stake: 14.0 inches

Event totals: 1.8” Snow/0.08” L.E. We’ve still got a bit of light snow falling on and off today, but there’s not much on the radar that suggests any substantial accumulations for this event in the immediate future. Details from the 12:00 P.M. Waterbury observations: New Snow: 0.1 inches New Liquid: Trace Temperature: 32.4 F Sky: Light Snow (1-2 mm flakes) Snow at the stake: 14.0 inches

Event totals: 1.7” Snow/0.08” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.5 inches New Liquid: 0.03 inches Snow/Water Ratio: 16.7 Snow Density: 6.0% H2O Temperature: 24.4 F Sky: Light Snow (2-5 mm flakes) Snow at the stake: 14.0 inches

Event totals: 1.2” Snow/0.05” L.E. Details from the 10:00 P.M. Waterbury observations: New Snow: 1.2 inches New Liquid: 0.05 inches Snow/Water Ratio: 24.0 Snow Density: 4.2% H2O Temperature: 25.5 F Sky: Light Snow (2-3 mm flakes) Snow at the stake: 14.0 inches

I’m not sure what time it started, but as of ~6:30 P.M. it was snowing pretty vigorously with some 1 to 2 cm flakes and ~3/4” of accumulation on the boards. It seems like fairly dry snow at this point, but I’ll have some info if I run an analysis later this evening.

Just eyeballing from the plot, it looks like SDD are in the ~50% range for Mansfield? Last week represented a good boost for the snowpack here at our site though – SDD were ~52% of average before that stretch, and now it’s up to 70% of average as of today. We’ve been doing much better on the season with respect to snowfall, but last week was still a solid contribution – it was a fairly symmetrical flip, bringing season snowfall from 8.2” behind average to 8.0” ahead of average.

I just cored the pack for CoCoRaHS today (I think they encourage folks to do it on Mondays anyway) and got 2.51” of liquid. It was actually a good time for a check on the water in the snowpack because there wasn’t any new snow yesterday, which was the first time since Christmas that I haven’t recorded at least a trace here.

The modeling definitely seems to be showing a northward trend with respect to that system, so it looks like we have the potential to get in on some precipitation even this far north. And indeed like you said, the other models do show that signal for moisture hanging around, just not as pronounced as what the GFS had. We’ll have to see where the trends go with this over the next couple of days. I was actually surprised at how quiet this next week looked in the modeling; we typically won’t have a week that quiet around here in the northern mountains unless full blown arctic high pressure moves in and leaves us in that dry, frigid air. Even during that very slow week before this past one, we still had 2 to 3 inches from those very weak bread and butter systems. There’s almost always a little something that pops up, and the mountains do their thing to at least get some flakes out of it.

Yeah, awesome upslope-land views over the past few days. This was definitely on my mind when I was out for a tour yesterday. The consistent snows and temperatures we’ve had over the past several days certainly had me pretty certain that the snow quality was there for lift-served skiing, but the appearance of your arctic hounds led me to go touring instead. When I saw highs in the single digits F for Bolton Valley yesterday, there was no way I wanted to sit still on the lifts in the wind vs. generating my own heat down in the protection of the forest. I got up to the Village around midday, and temperatures were indeed in the mid-single digits F as the forecast had suggested. Between all the backcountry touring and Nordic folks that I saw, there were plenty of people out on the lower trails, but farther out into the higher trails by the Bryant Cabin, I saw probably a handful of groups. Overall, you could tell by the vibe that people felt it was great weather for these types of activities. The additional 4 inches of fresh champagne that the resort had picked up really just served to top off the already crazy levels of fluff that covered everything. I saw some great views as soon as I arrived in the Village, so before gearing up for my tour, I took a quick walk around the Village and grabbed some scenic shots of the snow. Once I started my tour and got into the forest, the amount of snow everywhere was just crazy – it was caked so heavily on the trees that you were surrounded by it on all sides. Starting up the Bryant Trail was like walking into some sort of white cathedral. I made depth measurements of the snowpack during my tour, and I found generally 26-27” around the 2,000’ level, and many spots that are getting dangerously close to 40” up near 3,000’. That’s pretty consistent with what the Mt. Mansfield Stake is showing. At the start of my tour off Heavenly Highway I was on some steep, 30+-degree slopes, and I was setting off sloughs that definitely spoke to the relative snowpack instability from the continuous day after day after day of snows without consolidation. I was perfectly safe where I was the very dense (too dense for great turns where I was exploring actually) forest, but I immediately though about how I wouldn’t want to be exposed in the ravines. So I guess it wasn’t entirely surprising to come to the forum to find a conversation about slides in Tuckerman. A few shots from yesterday’s tour:

I’ve been checking it out for our site for a few years now, ever since Ginx pointed it out and the fact that CoCoRaHS stations are in there. I’ve found it generally to be quite good for my site. It definitely takes the empirical observations into account at times (see the data assimilation points in the plot) to at least augment the modeling, but they don’t seem to just immediately lock the modeling to the actual observed data points when they do the assimilations from what I’ve seen (and as you can see in the plot below). I don’t really follow the data for other sites to see how well its modeling reality, but I bet the meteorologists can provide more input on that. I’d suspect results are going to be better with the modeling if you’ve got consistent data input, such as at a CoCoRaHS or co-op site, but it’s not too hard to imagine that if you’ve got a site with zero empirical observations and 100% modeling (I’m not sure if they do that), the output could get quite far off from reality.

I hadn’t really checked the weather models much this week aside from a quick look in the short term to see if anything had changed for the bread and butter storms, but I just took a look ahead and I’m seeing some potential snow in our area on Tue/Wed? If it was just one model I’d guess it was nothing of note, but I just saw it on multiple models. The GFS seems to be trapping some moisture that hangs around for quite a while after the system passes. I guess we’ll see what the BTV NWS thinks about it in their afternoon AFD.

Oh, and the NOHRSC output does have a standard panel that tries to get at the snowpack layers (lower plot in the image below), and I think it’s roughly getting at the layers that PF is talking about. You can see the modeled settling in the very top layer of fluff, and at the very end of the modeling timeline what even looks like some compression in that lowest layer of faceted snow he mentioned:

Yeah, the snowpack topped out at ~18” here the other day, and it’s dropped a couple inches to 16” now. My last snowpack liquid analysis was on the 19th, when then snowpack had just shy of 2 inches of liquid in it. Based on what we’ve picked up in the past several days, we’re probably in the range of ~2.5” of liquid at this point? As I mentioned the other day, it looks like the NOHRSC modeling for our site (plot below) had the snowpack SWE a tad high because some of the Winter Storm Malcolm liquid when the temperatures were marginal probably percolated down through the snowpack here, and their modeling didn’t seem to account for that. They have now done a couple of assimilations of the actual data I’ve sent in (green lines on the plot), and I think they’ve reigned in the disparity a bit. The NOHRSC plot currently has our average snowpack density here at around 20%. As PF mentioned, there’s plenty of fluff on top in the form of dry snow from these recent days, so I know we’ll see some settling of that. But, there’s that very stout middle layer from the dense part of Winter Storm Malcolm that won’t settle much, and then a sugary/faceted layer below that representing the previous snowpack. I think it’s generally going to be the top portion of the pack settling as we go forward, so we’ll settle some, but it’s not as if the snowpack depth will get cut in half.

Ahh, it becomes much clearer now why Phin has been so very insistent about having that snowpack in place at the house. I’d be stressed as well if my main spiritual/emotional outlet during the winter was in jeopardy. We’re definitely glad he’s got the new spot in NNH.

LOL, don’t worry bwt, “epic” is totally subjective and fine to use whenever you want. As a skier, let’s just say that’s clearly a good sign if the word is even coming up in the conversation. Indeed, as PF alluded to, as a scientist, what I like about this forum is that one can dive into the data and actually get a sense for where things really stand vs. just simply relying on hype, poor memory, weenie hyperbole, agenda, opinion, anecdotes, recency bias, etc. etc. And I love that the meteorologists on here will often pull out real data to shut down misconceptions. I get it that for many folks, the forum is more focused on the entertainment aspect, and that’s great, but I really like the science/data-driven side a lot. A great analogy for what the forum is like from my perspective (and I mean the main threads for the most part, the NNE thread is pretty even-keeled), is like listening to Dr. Fauci talk about the COVID-19 pandemic on one hand, vs. listening to Donald Trump talk about the pandemic on the other. One of those presentations is more for show, publicity, entertainment, popularity, etc., whereas the other deals more with the nuts and bolts. One (you can probably imagine which one) is rather cringe-worthy from the perspective of someone who has been training and working in science for decades, and the other just clicks and makes sense. I’m clearly biased in my preference of course (Dr. Fauci was technically my boss during my years at NIAID), so it’s posts of that sort where I put a lot of my efforts. It is funny to think of us pulling out the data to tell folks how excited they should be, LOL. Hopefully I’m not overselling the past week with this one:

I’d been meaning to follow up on my initial “sub-epic” comment for bwt with an example, and it’s nice to see from the discussion that I wasn’t totally out to lunch somehow relative to the perspectives of some of the other NNE mountain veterans in here. As you can see from my comment above, I was thinking that for the period to more appropriately qualify as “epic”, we’d want to see some snow totals in the 1.5X to 2X range of what we saw this past week, and I wanted to grab an example. One that jumps to mind was that Feb 18-24 period in 2009, which did have back-to-back synoptic storms along the line of what PF mentioned as a possibility. I copied one of my forum posts from that period: That brings our total for this event to 18.2 inches, and our total for the back to back storms is 33.4 inches. As I suspected, some of the mountains have now hit six feet of accumulation from the last six days of snow. My daily email from Bolton Valley this morning had this to say: Six Feet of Snow. “Looking back at the log we keep of snowfall totals for the year I can hardly believe the last six days. It seems as if I am dreaming. We have measured snow of a foot or more on four of the last six days. We have a six day total of six feet. That's taller than most people. That's two yards of snow.” Here are some of the two-storm totals for local areas on the Green Mountain spine, listed north to south: Jay Peak: 68” Smugg’s: 54” Stowe: 52” Bolton 72” I was thinking there had to be periods where places like Jay Peak, with their penchant for upslope, have pulled in something in the 80-100” range in roughly a week duration (something roughly 2X what we saw this week), so I was glad when I saw that PF threw in that 80” value in his comment. Of course, this is all just dealing with the numbers and perspectives of various people – don’t let that get in the way of anyone who personally had a week that was epic for them. I think the veterans around here just wanted folks to have a sense for the fact that we’re nowhere near the ceiling on how weeks can go around here. If we get one of those systems that can hit up here where we get the full brunt of a big synoptic snowstorm and it tracks appropriately to drop a huge upslope event on the back side (I see PF mentioned 36” of upslope in 36 hours), that’s when the resorts can quickly get those 40”, 50”, or even 60” storm totals. Using the detailed snowfall numbers for individual storms on my site, and knowing the fairly consistent correlation of roughly 2 to 1 for snowfall at the local ski resorts of the Northern Greens relative to our site in the valley (which actually works fairly well on both a season-long, and storm-by-storm basis), I can provide estimates for the average frequency of storms of certain thresholds for the resorts of the Northern Greens. These numbers won’t really work for other parts of the region of course, but they definitely apply for bwt’s location at Jay Peak: Storm Size (snowfall) vs. Frequency of Occurrence 24”+: ~3 per season 30”+: ~2 per season 36”+: ~1 per season 40”+: ~1 per season 48”+: ~1 every other season So, on average for winter storms, the local mountains here should get about 3 two-footers a season, 1 three-footer a season, etc. etc. Note that this is not going to represent the frequency for mountains in other part of the Northeast of course, and certainly not for any valley locations, so folks hopefully aren’t looking at this and thinking that they’re going to be averaging a 40-incher every season at their house, or even their local ski area if it’s outside the Northern Greens. But if we’re doing that well in this area from a storm, then it’s probably not going to be an all-out famine at nearby mountain sites. This past week is a bit tough to compare in terms of the individual storm frequency estimation methodology because the snow was derived from what my records show as four storms. Here are the various storm totals from our site: 1/16/2021: 12.2” 1/19/2021: 2.9” 1/20/2021: 2.9” 1/21/2021: 8.4” The first storm in that series (Winter Storm Malcolm) represents the main synoptic one with the dense snow that kicked off this past week, so if you following my usual methodology, that one should be roughly a two-footer for the local resorts. PF did mention that the mountain-to-valley snowfall ratios haven’t been quite as disparate as usual for this week’s snowfall (one can take that as either “yay” for the valleys or “bummer” for the mountains I guess), but how did my data correlation work with respect to Winter Storm Malcolm? If one goes back to my storm summary for the VT ski areas for Malcolm on Monday, you’ll see that when it was all said and done, the resorts along the spine had picked up 18-24” from that one. Yeah, the Northern Greens specifically, were only topping out around 20” in this case, but these things are all going to be ± to some degree of course, and I can certainly live with that. That’s actually the first 12”+ storm I’ve got in my records for this season, which means (barring some early season elevation bomb that wouldn’t have affected our site) that must be the first roughly two-footer for the Northern Greens this season? That potentially speaks to the way the season has gone around here thus far, but is it outrageously late for the first two-foot storm? As I was writing this, I realized that I’ve got some data for that. The average date for the first 12” storm of the season here at our site (thus an ~24” storm for the local mountains) is January 3rd, with a pretty large S.D. of 34 days. So, this would be a couple weeks later than average for the first storm of this size in the mountains, but it’s still nothing unheard of. This past week should definitely get a gold start in terms of mountain snowpack/ski quality recovery efforts though, as bwt proposed. The zero to hero factor for the week was excellent.

Event totals: 8.4” Snow/0.21” L.E. We’re really cleared out now, so it looks like this will be the last accumulation to report from this system, and the numbers above should be the final totals. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.1 inches New Liquid: 0.01 inches Snow/Water Ratio: 10.0 Snow Density: 10.0% H2O Temperature: 1.6 F Sky: Mostly Clear Snow at the stake: 16.0 inches

There was technically that more substantial synoptic storm to kick off this run, but there’s really no two ways about it at this point; you’ve definitely been able to experience a solid NNE bread and butter week now Phin. It’s funny, the whole “days and days” thing is actually a sarcastic snow weenie meme that they use in the main threads sometimes, but it’s not a joke up here, it really does that. Actually, tomorrow will be the 30th day in a row that we’ve recorded a trace of more of snow at our site, so we’re in quite a long run of flakes since Christmas

So you’re saying we have to deal with this guy and all his buddies now? Sigh… he has a mean look.

Event totals: 8.3” Snow/0.20” L.E. Well, flake size is way down today, and at 5.0% H2O this is the densest snow I’ve seen from this whole storm. We’ll blame those damn arctic hounds PF was talking about and assume they’re messing up the dendritic growth. Details from the 12:00 P.M. Waterbury observations: New Snow: 0.2 inches New Liquid: 0.01 inches Snow/Water Ratio: 20.0 Snow Density: 5.0% H2O Temperature: 17.1 F Sky: Light Snow (1-3 mm flakes) Snow at the stake: 17.5 inches

Event totals: 8.1” Snow/0.19” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 2.0 inches New Liquid: 0.05 inches Snow/Water Ratio: 40.0 Snow Density: 2.5% H2O Temperature: 12.0 F Sky: Flurries Snow at the stake: 18.0 inches

I hadn’t checked on the resort snow totals for the past week, so your comment got me thinking and I just assembled the list below to see where things stood as of this evening. As expected, Jay Peak is leading the pack with 46”. For perspective, at least with respect to just snowfall numbers for the past week, I don’t think we’re really in “epic” territory. I’d say the week is actually better characterized as “very solid”, or “strong”, or “great”, or something along those lines. Obviously these terms are highly subjective, but for “epic” (sort of a “once-a-season” type of week), I’d want to see snowfall numbers 1.5X to 2X what we’ve seen this week. The snowfall numbers below, or even higher totals, could easily be picked up in one solid storm cycle over the course of a couple of days, and then if the rest of the week has solid daily snows, or you happen to get a second big, synoptic storm, you can imagine where the numbers would end up. I think for describing the overall ski conditions, “epic” might have a better chance, simply because it was that perfect combination of starting off with a hefty shot of beautifully dense, high L.E. snow, followed by day after day after day of very solid refreshers of midwinter dry powder. That’s seriously what makes for the best ski surfaces, so conditions have just been really good. And, the “zero to hero” factor sort of makes it feel somewhat more epic than it really is. I still think we’re falling short of “epic” all around though – the existing snowpack was just way too shallow starting off the week to immediately go to that “no holds barred” type of off piste skiing. To that point, I see that the snowpack at the Mt. Mansfield Stake is 36” (vs. an average of 44”), so we’re still below average in that regard and really haven’t even reached the point of the 40” rule yet. I feel like we’ve at least got to get there before we get into “epic” territory. Of course it’s all subjective, but no doubt it’s been a very solid week for snowfall and ski conditions around here. It would be interesting to hear where PF would place the week for Stowe based on his extensive experience. North to south listing of available 7-day snowfall totals from the Vermont ski areas: Jay Peak: 46” Burke: 18” Smuggler’s Notch: 32” Stowe: 35” Bolton Valley: 29” Mad River Glen: 30” Sugarbush: 30” Pico: 36” Killington: 36” Okemo: 23” Magic Mountain: 19” Mount Snow: 35”

Event totals: 6.1” Snow/0.14” L.E. Details from the 10:00 P.M. Waterbury observations: New Snow: 0.8 inches New Liquid: 0.02 inches Snow/Water Ratio: 40.0 Snow Density: 2.5% H2O Temperature: 21.9 F Sky: Light Snow (1-2 mm flakes) Snow at the stake: 17.0 inches