J.Spin

Yesterday’s ski tour up at Bolton Valley yielded some great powder skiing, so with today being sunnier and warmer, my older son and I headed up for another tour on the Bolton Valley Nordic & Backcountry Network. I’d gotten a good bead on the conditions in the Bryant Cabin area during yesterday’s tour, so I took my son on the same general route today in the 2,000’ to 2,800’ range, and we just varied it up a bit as we sought out untracked areas. The resort reported a couple of inches of new snow overnight, so between new accumulations and settling, powder depths were similar to yesterday, with 14-15” on the low end, and 21-25” on the high end. It turns out that the wind slab and more condensed areas of powder I’d encountered yesterday were strictly in the higher elevations above 2,600’ or so, but it wasn’t really until I’d been through areas again today that I was able to confirm that. Similar to yesterday, we were skiing generally western aspects today, so leeward aspects may be unaffected with the wind slab. In any case, once you got below that threshold elevation where the wind had its effects, the quality of the powder took a noticeable bump up, and that was the case for every line we skied today.

January has just finished up and we’re at the approximate midpoint of the snowfall season around here, so I have the plot with the latest seasonal snowfall progression from our site. The current season is the red trace in the plot, and since that flurry of activity leading up to Christmas, snowfall strolled along at a roughly average pace until about the second week of January. The slope of the average snowfall trace can be used for comparison, but at that point the pace of snowfall actually fell off to a bit below average. This season definitely started to fall behind the snowfall pace of those comparator seasons I have in the plot, and that’s how it was going until that big snowfall spike near the end of January representing Winter Storm Fern. That storm and the couple of additional events we’ve had this week have brough this season right back up into the mix among those other seasons. Starting with the numbers in hand at this point of the season, the stats can be used to get some odds of where the overall seasonal snowfall may end up: Chance of reaching average season snowfall of ~160”: 96.0% Chance of reaching season snowfall of 200”: 38.0% Chance of matching the 1st ½ season snowfall to reach 240”: 1.4% Clearly it would be quite unlikely for this season to continue with the snowfall pace we’ve seen so far for this first half. We’ve never had a season reach 240” of snowfall during my period of record here – none of those other strong seasons in the plot reached that total. I also have the storm list for the first half of the season below. I haven’t assembled stats on the pacing for the number of storm we get during the season, but we’re probably ahead of average there. If storm frequency were to continue at this pace, we’d have over 80 storms on the season, which is way above average – the greatest number of storms we’ve seen in a single season thus far at this site has been 64. If I were to run the numbers, I bet we’d find that there are fewer storms in the second half of the season relative to the first half. As we head father into the winter season, the tenor/typical weather pattern feels different than the November and December regime that has relatively warm Great Lakes and often provides lots of smaller systems/lake-effect events with frequent snowfall. But, every season is different, and we’ll see what Mother Nature decides to do this time around.

We had another cold January Saturday on our hands today, but temperatures were certainly up a notch from what we encountered last weekend. Instead of valley temperatures hovering around 0 F for highs, they were up around 10 F today, so I headed up to the mountain for a ski tour. The temperature was still only around 0 F when I arrived in the Bolton Valley Village around midday, and it was busy, but not “holiday weekend” type of busy, and I was able to get a parking spot right in the backcountry access lot. Thanks to Winter Storm Fern and the subsequent systems that have come through the area, we’ve had over two feet of new snow in the valley over the past week, and the Bolton Valley snow report was indicating 30 inches of snow at the resort in the past 7 days. The powder is still deep and plentiful, but the powder quality certainly isn’t up where it was right after Winter Storm Fern. That storm cycle concluded with a period of incredibly dry 1-3% H2O powder; that champagne was so incredibly light and dry that it skied like a dream on any sort of pitch. Powder of that airy nature would naturally settle rapidly on its own, and it’s easily been crushed by the snows of these more recent storms. The powder from this week’s smaller systems certainly wasn’t too dense, with snow densities in the 2-7% H2O range, but the tail end of our most recent one did finish off with some fine-grained flakes that came around 10% H2O. In combination with the powder settling on its own and under the new snow, I even encountered some areas of wind slab out there on my tour. All told, the combination of depth and density in the powder out there today couldn’t support good turns on low-angle terrain, so you had to hit mid-angle terrain or steeper. I toured up and around the Bryant Cabin today at elevations in the 2,000’ to 2,800’ range and settled powder depths were typically 14-15” on the low end, and 21-25” on the high end. So, I may be dissecting the finer points of the snow density, but there’s absolutely some fantastic powder out there. I initially descended through Gotham City and did a bit of exploring on new terrain, then I did another quick ascent to get a descent through Gotham in the Gun Sight area, which yielded some of the best turns of the day. There really hasn’t been a ton of traffic in many areas of the Nordic and Backcountry Network yet, so as long as you find those areas with appropriate pitches for the deep powder, you can get in some really nice turns. The resort looked like it was actually getting a little busier when I was leaving in the early to mid-afternoon period – the sun was coming out and the temperatures were climbing a bit, so that was the little extra nudge that people might have needed to get out for a few runs.

Since we’re right around the midpoint of the snowfall season around here, I did a quick check on where the Vermont ski areas stand for season snowfall thus far, and the north to south listing of totals is below. The four resorts along the spine of the Northern Greens are all reporting 200-300”+ for the season so far. It would naturally be difficult to keep up that same snowfall pace for the entire second half of the season, but that would certainly result in some solid overall snow numbers. As is typical, the numbers drop off a bit to <200” for the ski areas in the Central Greens, and some areas are even <100” in the Southern Greens. These numbers are all subsequent to the strong boost from Winter Storm Fern last weekend, so some of those snowfall numbers in the south must have been quite low prior to that. A quick look at the season snowfall totals thus far for the Vermont CoCoRaHS sites shows that several of them have seen more snow than any of the resorts in the Southern Greens - and CoCoRaHS sites are generally going to be valley/non-mountain locations. That disparity may be a function of the season thus far being characterized by more progressive/northern jet stream patterns vs. coastal or southern jet stream events. Jay Peak: 309” Burke: 118” Smuggler’s Notch: 218” Stowe: 218” Bolton Valley: 222” Mad River Glen: 138” Sugarbush: 154” Saskadena Six: 50” Pico: 140” Killington: 140” Okemo: 84” Bromley: 117” Magic Mountain: 73” Stratton: 106” Mount Snow: 88”

As of yesterday morning, the mountains had picked up another few inches of snow from the disturbance coming through the area on Tuesday, so I headed up to Bolton Valley for a tour. The Timberline Quad was set to start running at 9:30 AM for the first time this week, so getting in ahead of that opening was the best bet for untouched snow ahead of the lift-served traffic. Temperatures have remained much better than the cold we saw over the weekend – with temps running around 10 F and minimal wind present, the skiing is a lot more comfortable, especially while touring. With the additional snow from the end of Winter Storm Fern and this more recent system, powder depths were a bit deeper yesterday than what I’d found on Monday. Depth measurements were more in the 15-20” range vs. the 12-18” range that was out there before. The powder didn’t come across quite as dry as what was out there on Monday, since the snow from this disturbance has been coming in with snow densities in the 3-6% range vs. those 1-3% readings from the end of Winter Storm Fern, but it was still fantastic midwinter champagne powder - you’d be hard pressed to tell the difference unless you were out there both days and paying close attention.

I’d initially thought of heading out for a lift-served alpine skiing session today to check out the snow from Winter Storm Fern, but while temperatures have been warming somewhat since the cold spell over the weekend, morning temperatures were still going to start out in the rather unappealing single-digit F range. Once the snow reports started coming in though, it was clear that there wasn’t much elevation dependence with the storm, and that made the idea of touring at Bolton’s Timberline area where the uphill route has just officially opened for the season, a bit more appealing. And with the Timberline Quad not running on Mondays and Tuesdays, the area was only going to see ski touring levels of traffic. It was clearly a god day for a Timberline tour, and a number of people had similar thoughts - there were more than a dozen cars in the Timberline parking lot when I arrived in the mid to late-morning timeframe. Temperatures had risen into the double digits F, and backside snows were continuing to add to the accumulations. By the midday timeframe I was finding a general 12-18” of powder depending on exposure. Areas with 12” weren’t quite enough to deliver bottomless turns on the steepest pitches, but 18” was enough to do it. The quality of the powder was simply fantastic, with a right-side-up gradient that started off around 11% H2O and tapered down to the 1-3% H2O range. It was so super dry champagne that it skied well on any pitch – you could crash the steep pitches, and the snow was so light and dry that it simply let you float your way down through even lower-angle terrain.

Well, you were absolutely right to be gun shy with respect to that type of forecast – how often do we actually get upslope-style snowfall ratios with surface temperatures around 0 F? I will say that thankfully, temperatures did come up quite a bit today – we got up to 15 F in the valley, which felt really nice. While that may not seem all that warm, without any wind it’s dramatically different from temperatures below zero F with brisk winds. Anyway, we certainly doubted whether or not Mother Nature could pull off those higher snow totals in the forecast at those temperatures, but she did. We just hit 20” on the storm as tonight’s snow is rolling through, and low and behold, we are just about to hit 0.75” of total liquid equivalent. So, it was just like the upper end our ~10”-20” point forecast range here suggested, and the overall snow to liquid ratio is around 27:1 for the storm. Kudos to the BTV NWS for their forecasting as usual. And for folks that got our for powder turns today, if you were wondering why the quality of the powder seemed like it was off the charts good… well, you weren’t crazy. The quality of the powder was off the charts. OK, well maybe it wasn’t quite off the charts, since I can, actually, chart out just why the powder skiing was of such incredible quality around here. As noted earlier in the discussion, the storm started off Sunday afternoon with a couple inches of 11.1% H2O/ 9:1 snow, then during Sunday evening, the snow to liquid ratio more than doubled, for another 7 to 8 inches of 4.2% H2O/24:1 snow. Then overnight, the ratio nearly doubled again, leaving about a half foot of 2.4% H2O/42:1 snow. Then through the day today there was another half foot of snow that fell in the 1-3% H2O range. Even for around here, that’s some impressively dry powder, and with the way that right-side-up density gradient came together, it skied really well. This certainly wasn’t an especially large storm by Northern Greens standards, but the very high quality of the powder that fell was definitely noticeable.

Well, the modeling certainly knew what it was talking about with the snow growth potential. At least when snowfall rates were on the higher side, I was seeing flakes up to 20-30 mm in diameter, but midnight observations here still had flakes up to 20 mm. I wasn’t sure if that 6 PM to 7 PM snow ratio would be maintained for the whole 6 PM to 12 AM block, but LOL, no worries there. This most recent block’s snow density just came in at 4.2% H2O for a 24:1 ratio – that impressive for an entire snow collection period, and indeed it’s right up there with the quality of upslope snow. This has certainly been some of the loftiest snow I’ve seen with temperatures hovering around the 0 F mark, so some unique conditions have come together with this system. At 24:1, even 0.75” of liquid produces 18” of snowfall, so the forecast numbers certainly aren’t crazy for areas that are in the banding.

The tenor of the snowfall had changed so much that I decided to run a quick liquid analysis on the new snow at 7 PM – it came in at 5.5% H2O for an 18.3:1 ratio, so indeed the snow to liquid ratio had essentially doubled from what it was earlier.

The snow thus far in the storm has seemed fairly dense, and indeed the 6 PM liquid analysis came in at 11.1% H2O for a 9:1 ratio. Flakes were generally in the 1-3 mm range this afternoon, but with that said, flake size has been increasing over the past hour or two. With that band that’s moved into the area, the snowfall rate has jumped up to the 1-2”/hr. range and I’m seeing flakes up to 10 mm in diameter. That’s more in line with the type of snowfall that would be needed to hit those higher end totals, and if I were to run another liquid analysis right now it would be much higher ratio snow. I’m not convinced that these snowfall rates and ratios would continue to be the norm overnight, but it’s nice to hear that some of the modeling is suggesting the potential is there.

Well, it’s wall-to-wall Winter Storm Warnings on the BTV NWS alerts map now that those cold weather alerts are gone, and that’s typically a good sign for a storm. I see that the latest Event Total Snow Accumulation map update has some areas of that 18-24” shading up here along the spine, and there’s a bit of that 24-30” shading down in the Southern Greens. The forecast here at our site does come in around that 10-20” range through tomorrow night, and the mountains are a bit more than that. Those numbers generally match up with the accumulations shading, but it’s a little tough to envision the high end of those numbers with the liquid equivalent that I’m generally seeing in the models (which seems to top out in the 0.75”-1.00” brackets). Accumulations could get there with some high snow to liquid ratios, but I’m not used to getting great snow ratios when the air is this cold – we often get that relatively dense arctic sand. The ratios are being mentioned a lot, so the dendritic growth zone setup must be there, and I guess we’ll see if this event is different and gives some lake-effect/upslope style snow ratios. What’s in the forecast is certainly a moderate resurfacing event, but it’s not even as large as Winter Storm Ezra from a few weeks back, which brought 1.24” of liquid here in the valley and even more to the mountains. This should be a nice addition of liquid equivalent to the snowpack in any case – I’m not sure if we’ve had a storm in the 1.0” liquid equivalent range since Ezra? And it’s always great to add to the snowpack when it’s already in really good shape and the surface conditions are relatively good as well – the ski conditions should only get better. This system (Winter Storm Fern) is rightfully getting a good amount of attention though because it’s affecting a relatively large amount of the country and some big population centers.

Hitting 70-80” snowpack depths is pretty typical for Mt. Mansfield and similar elevations in the Northern Greens in most seasons as the Mt. Mansfield Stake data suggest, with 80-100” depths a bit less common. Strong seasons will hit 100”+ snowpack depth with either the right combination of liquid equivalent and/or lack of large storm cycles with substantial warmth – I think last season was just above the 100” snowpack mark at its peak. With everything so evenly covered and buried, it can be difficult to get a sense for the depth unless you are in areas that have sharp wells to the ground as PF discussed or dig a pit like backedge showed. One approach that has always helped set up the perspective for me is warm season hiking above Stowe’s Cliff House, not too far from the area that PF describes in his post. When you hike up there in the summer among the car, truck, or even house-sized boulders and realize that many of those areas are actually smoothed over into snowfields that you’re skiing in the winter, it sort of hits home. Once you get up in that 100”+ range of depth, you’re at that height of a one-story building, so it’s not hard to see how all those huge obstacles can get covered. The image below shows summertime shots of some of the types of terrain features there that are covered, and then the bottom right of the collage is a shot of what it looks like in the winter when we were out with some of the kinds in our school’s ski program guiding them in the alpine. The next image is a great representation of how smoothed out it gets, and there are more winter shots of the area in my web page archives.

PF, am I seeing the recent snowpack depth report numbers correctly to suggest that the current snowpack (74”) at your High Road Plot at 3,040’ is coming in deeper than the snowpack (70”) at the Mt. Mansfield Stake at 3,700’? Those two spots aren’t all that far away from each other, they aren’t too disparate with respect to elevation, and they both represent similar leeward aspects of the mountain, but is that true and does the lower elevation depth outpace the higher elevation depth frequently? I’ve never routinely followed the snowpack depths at your snow study plots because I typically only see them when you bring them up in a forum post, but now that Matt Parrilla appears to have them on his Mt. Mansfield Stake page, I’m seeing them all the time (he also monitors some lower elevation CoCoRaHS sites around here in the Northern Greens like ours in Waterbury). I didn’t know your daily depths from the plots were even available – where does he get them from? Or (it’s hard to imagine) are his 3,040’ and 1,550’ numbers coming from somewhere else other than your High Road and Barnes Camp plots?

I wouldn’t describe our recent weather pattern as much of a classic Northern Greens bread and butter setup with Alberta Clipper systems driving right though the area every other day or so; it’s been much more a hodgepodge of systems passing fairly far to the north, cold fronts, lake-effect snows, squalls, and stuff like that. Those types of events are certainly a big part of our usual winter snowfall, but it just hasn’t seemed like the locked-in consistency has been there recently the way it was often around in November and December. In any case, the past couple of days have certainly delivered as PF’s images show, and Bolton Valley’s snow report speaks to that, with 10 inches reported in the past 48 hours. I hadn’t planned to ski today with no notable systems in the area, but my older son was up at the mountain yesterday and was quite impressed with the amount of new snow he encountered. He’d brought some fairly narrow alpine skis, expecting generally packed/groomed snow, but he was up there when some of the recent squalls started hitting, and the inches built up rather quickly. When he was telling me about it later in the day, he said that he should have brought fatter skis because he was getting into boot top powder quite often. His report was enough to get me out for a ski tour this morning, and the timing was also good with respect to temperatures –the mountain was in the teens F today, which is much better than it looks like it’s going to be over the next couple of days. I was last out on the hill on Monday, and at that point I was already impressed with how much the powder conditions below 2,500’ had improved relative to the prior few days. These past couple days of lake-effect snow, fronts, and squalls have definitely continued that improvement to the point where I didn’t even notice any difference in the quality of the powder skiing above and below 2,500’ today. I toured in the 2,000’-2,800 elevation range today, and while the powder does get deeper with elevation, the subsurface has improved so much with settling/drying, and the depths/total liquid equivalent at even 2,000’ have increased enough that the quality of the skiing doesn’t drop off as you descend. Here are the approximate powder depths that I measured during today’s tour 2,000’: 6-8” 2,500’: 8-10” 2,750’: 10-12” There were even more rounds of squalls today with decent accumulations, as well as a potentially larger storm on the way toward the end of the weekend, so the quality of the conditions should continue to get even better going forward.