J.Spin

Event totals: 2.9” Snow/0.22” L.E. We picked up another 0.4” of snow overnight, which was somewhat unexpected, but the forecasts/discussions did indicate the chances for this type of snow during the first part of this week. The current BTV NWS discussion suggests that this precipitation is still related to the same storm we’ve been dealing with for the past couple of days, which is now south of Nova Scotia, and the radar (below) clearly shows that moisture coming from the east, so I’m rolling these numbers in with the current system. Area Forecast Discussion National Weather Service Burlington VT 635 AM EST Tue Jan 5 2021 NEAR TERM /THROUGH WEDNESDAY/... As of 635 AM EST Tuesday...Mainly uneventful weather expected over the next 42 hours despite plenty of clouds. Upper level trough extending west- northwest from offshore low pressure south of Yarmouth, NS continues to pull some mid-level moisture westward back into northern New England/nrn NY this morning and expect this trend to continue into tonight. Therefore, will continue with slight to lower chances of flurries/light snow shower activity across mainly northern counties during this period as forcing will remain weak. By Wednesday the offshore low and aforementioned upper trough begin to pull east fostering a slight uptick in the low level pressure gradient and northwesterly surface winds. This may allow some partial clearing in the Champlain and CT River Valleys toward afternoon. Temperatures to remain slightly above seasonal norms in the upper 20s to mid-30s. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.4 inches New Liquid: 0.03 inches Snow/Water Ratio: 13.3 Snow Density: 7.5% H2O Temperature: 30.0 F Sky: Cloudy Snow at the stake: 7.5 inches

I’d been meaning to check on where we are at our site, and had a chance to look at the numbers today. Snowfall: The combination of a strong November and weak December came together to really keep us right around average on cumulative seasonal snowfall over the past couple of weeks. We’re just slightly ahead of average pace as of today with 55.7” on the season, vs. a 54.6” average to this date. This season will presumably fall off the average pace a bit if this week is slow with respect to snowfall; we need 1-2”/day this time of year to stay up with the mean. Snowpack depth: Today’s snowpack depth at our stake is 9.0”, which is actually quite close to the mean of 9.7” for this date. SDD: Current snowfall for the season and current snowpack depth suggest that things are pretty typical, and indeed they are in those respects, but SDD incorporates a bit more of the season’s history with respect to snow preservation. SDD to date at our site is 106.5 inch-days, which is less than half the 243.5 inch-days average for this date. So, while snowfall and current snowpack depth are typical, it’s definitely been a below average season in terms of snow preservation thus far.

December Totals Accumulating Storms: 11 Snowfall: 23.4” Liquid Equivalent: 4.69” SDD: 54.0 Calendar Year Liquid: 50.64” I’ve had a chance to put together the December snow numbers for our site, and some notes about them are below: · Snowfall was definitely on the lean side for December this season. It’s interesting to note that we picked up the same amount of snow in December as we did in November, which speaks to a solid November and a poor December. This December’s snowfall was actually the third lowest in my 15 seasons worth of records; only 2006-2007 and 2015-2016 were lower. · Also of note is that SDD were quite low at 54.0 inch-days, whereas the mean is 180.8 inch-days.

Thanks PF, that’s really insightful stuff that the average resort visitor is not going to be aware of. I always knew that snowmaking was much more efficient down at those lower temperatures (to a point, since I know you’ve said that are issues when it gets too cold), but I had no idea the temperature threshold for decent efficiency (mid 20s F) was so low. Obviously wet bulb temperatures etc. play into that too, but wow, I figured the big efficiency issues didn’t start until you got to around 32 F and above. As a skier, I’ve been loving these moderate temperatures we’ve had thus far in December and January – cold enough to get snow and hold it (barring the storms where we get into the warm sector significantly of course), but not so cold that we’re freezing our butts off out there. I look at the forecast and see mountain high temperatures in the 20s to near 30 F and think, “sweet!” – I had no idea that the departures were representing such a challenge for snowmaking.

Event totals: 2.5” Snow/0.19” L.E. Since it was Monday, I also cored the snowpack at observations time this morning and found 0.84” of liquid. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.3 inches New Liquid: 0.01 inches Snow/Water Ratio: 30.0 Snow Density: 3.3% H2O Temperature: 28.4 F Sky: Flurries Snow at the stake: 9.0 inches

With the influx of snow that the area has seen from Winter Storm John, the snow conditions improved dramatically this weekend. Based on the liquid equivalent we picked up here at the house, I bet the local mountains picked up something in the range of ¾” of liquid, which is a game-changer relative to where things were before. The conditions had improved enough that I headed up to Bolton for multiple sessions this weekend, so I can pass along some snow updates and images. On Saturday morning I decided to go for my first lift-served turns of the season – only the main mountain is open at this point, since coverage is still too thin down at the lower elevations of Timberline. It was snowing steadily with some big flakes when I arrived at the mountain, and I found about 4 to 5 inches of new accumulation in the Village areas at 2,000’. The snowfall tapered off to light snow during the midmorning period, but really picked up to some heavy inch/hr snowfall when I was leaving a bit before noon. That was when the back side of the storm was coming through, and the wind jumped up a bit there, but prior to that the weather was fantastic with temperatures just a bit below freezing and no wind. There was obviously some surface snow in place from previous systems because I was generally finding powder depths of 6-9” at the 2,400’ level. Skiing was good, with enough snow to resurface low to moderate angle slopes, and listening to skiers and riders on that terrain you’d hear absolutely nothing. On higher angle slopes you could still hear contact with the old base snow, so it was obvious that ¾” of liquid can only do so much with holiday levels of skier traffic. With the way it had been dumping inch/hr snowfall when I headed home around noontime, I decided it would be worth another session in the afternoon. This time I went for a tour on Wilderness, which had its uphill route officially reopened as of Saturday thanks to the accumulations from Winter Storm John. There had been additional snow, and I’d say 6-10” of powder above the base snow would represent a good summary of what I found overall in the 2,000’ to 3,000’ elevation range, which was a combination of the snow from this storm on top of the accumulations from previous events. With Bolton having access to the entire Wilderness Lift area of moderate-angle, cut trails all starting above 2,000’, I’m sure a lot of folks see it as a very good option with the rather thin base currently in place at lower elevations. That, and the fact that it was a holiday weekend, meant that there was a lot of uphill traffic. Fortunately, there was still decent access to untracked powder along the edges of trails, and the turns were quite good and bottomless on low and moderate-angle terrain with the recent snow we’ve picked up. Today I headed back up for a tour with my younger son, and we went a bit farther afield in the Wilderness area in search of untracked powder. It was definitely harder to come by this afternoon, because there has been heavy ski touring traffic this weekend. The amount of traffic is relative of course, and nothing like you’d get with lift-served skiing, but after an entire holiday weekend worth of people touring, the untracked snow on the trails had been just about picked clean. One factor in the traffic is that folks aren’t yet using all the acreage of tree skiing; the trees were generally untouched because people know that it’s still just a bit too thin in there for the skiing to be practical. If we get one more good snowstorm with an inch of liquid, then the low-angle trees will be in play. A few images from the weekend:

This was a nice addition to the recent snow with 0.18” of liquid equivalent here through 10:00 P.M., and we know every bit helps out with improving the base. We’ve had a bit more snow since those observations, but it’s tapered off now. We’ll see if anything else flares up tonight. It does look like a surprisingly quiet week for snow around here, with no obvious bread and butter systems in the northern stream. After this system, there are some slight chances during the first part of the week, and I guess we’ll just have to see what else might develop. As NoPoles mentioned, this is a much nicer way to potentially have a quiet week vs. it being due to one of those presses of frigid arctic air that we sometimes get in January.

Event totals: 2.2” Snow/0.18” L.E. Details from the 10:00 P.M. Waterbury observations: New Snow: 2.2 inches New Liquid: 0.18 inches Snow/Water Ratio: 12.2 Snow Density: 8.2% H2O Temperature: 28.6 F Sky: Light Snow (1-6 mm flakes) Snow at the stake: 8.5 inches

We’ve definitely had some solid snowfall rates at times this evening – I’d look out and see what definitely looked like 1”/hr snow. We haven’t had that rate consistently of course, but I see 1.5–2” of accumulation on the boards since this event started and we’ve got snowfall that seems pretty close to 1”/hr at the moment.

As others have noted, it looks like that system will be too far east to really push much upslope back into NNE, but there’s potential snow associated with the front side of the system tonight, and the BTV NWS discusses the chances for snow showers for the first half of the week. Looking at the models, they’re apparently referring to the bit of moisture that the storm does push back this way even though it’s relatively far off shore. Area Forecast Discussion National Weather Service Burlington VT 936 AM EST Sun Jan 3 2021 .SYNOPSIS... Dry for much of today, then another storm system will bring the chance for some light snow tonight into Monday. Most will see less than an inch, with parts of south central Vermont seeing around 1 to 3 inches. The potential for light snow showers will continue through mid-week, along with temperatures near seasonal normals. Chances for snow showers diminish across the latter half of this week.

Wow, that's pretty darned consistent with what I got - essentially the exact same 9 to 1 snow to L.E. ratio for the overall storm.

Oh, I totally agree that those stood out, even in just reporting the upper elevation numbers as I usually do for my lists. It’s one of the reasons I like to put these north to south summaries together though – it lets one see the snowfall trends and deviations around here with respect to latitude. Sometimes the ups and downs make sense, and sometimes they’re not as straightforward. It’s really cool to have the spine of the Greens running 250 miles with all the resorts giving high elevation observations though. They’re not going to have the rigor of something like a first-order station in their observations of course, but they give a decent idea of what went on with each storm up and down the state.

I’ve put together the north to south listing of available snowfall totals from the Vermont ski areas for Winter Storm John. It’s interesting to note that totals fell off as on heads south, as expected with the intrusion of mixed precipitation, but after bottoming out in the Okemo area, the totals increased a bit heading southward. Jay Peak: 8” Smuggler’s Notch: 9” Stowe: 6” Bolton Valley: 6” Mad River Glen: 8” Sugarbush: 6” Pico: 4” Killington: 4” Okemo: 1” Bromley: 2” Magic Mountain: 3” Stratton: 3” Mount Snow: 4”

Event totals: 5.8” Snow/0.65” L.E. That should be it from Winter Storm John at our site, so the final numbers are 5.8” snow from 0.65” L.E., for an overall snow to L.E. ratio of ~9. Details from the 6:00 P.M. Waterbury observations: New Snow: 0.3 inches New Liquid: 0.01 inches Snow/Water Ratio: 30.0 Snow Density: 3.3% H2O Temperature: 26.2 F Sky: Cloudy Snow at the stake: 6.5 inches

If the low pressure sits in the Gulf of Maine, or anywhere from there up to Northern Maine, or the Gaspé, or even the Maritimes, a period of extended upslope snow is a possibility. Low pressure sitting in Northern Maine can be great for the Northern Greens, but any of those places can deliver if they wrap around moisture from the Atlantic and get that northwest flow into the mountains here. Decent positioning for upslope can vary depending on the storm’s extent of circulation, wind direction at different levels, and various other factors. And I’m sure the different upslope zones here in the mountains of NNE will have different optimal setups for their snow. It’s kind of like an extra insurance policy on some systems if the front side snow misses or ends up being a dud. Naturally, the snowiest scenarios are when you get walloped by the initial pass of the storm and then the storm sits in a position to deliver upslope. That’s when the mountains here can get feet upon feet of snow. What you don’t want to see (if you want to get the most out of that bonus upslope snow) is a system that skirts along the coast and then simply maintains that latitude and heads east. I think we had one of those earlier this season. As PF’s map shows, some models do suggest the potential for upslope with this next system if it hangs out off the coast. It can happen just as you say though, with light snows for an extended period. Sometimes you can get moderate, or even heavy snows, but this setup doesn’t look like that at this point.

Event totals: 5.5” Snow/0.64” L.E. It looks like we’re into the next phase of the storm now, and I can see on the radar that moisture appears to be coming in more from the northwest. Details from the 12:00 P.M. Waterbury observations: New Snow: 2.4 inches New Liquid: 0.25 inches Snow/Water Ratio: 9.6 Snow Density: 10.4% H2O Temperature: 34.0 F Sky: Snow (5 to 20 mm flakes) Snow at the stake: 6.5 inches

I checked the boards at ~8:00 A.M. and found 1.4” of accumulation since the 6:00 A.M. analysis/clearing, snowfall rate has averaged ~¾”/hr. during the period. That’s definitely the average of some slower and faster snowfall periods though, because there was a time earlier where the snowfall had lightened up considerably.

Event totals: 3.1” Snow/0.39” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 3.1 inches New Liquid: 0.39 inches Snow/Water Ratio: 7.9 Snow Density: 12.6% H2O Temperature: 28.4 F Sky: Snow (2 to 10 mm flakes) Snow at the stake: 4.0 inches

I see we’ve got some flakes coming down here in Waterbury, so the storm has pushed into this area.

This afternoon’s update from the BTV NWS should be the last one before the onset of the current system moving into the area. There have been some changes in both the advisories map and the projected accumulations map, with the BTV NWS AFD noting a couple of related forecast changes. The first is regarding a slightly earlier onset time for snow, and the second deals with snow totals, as discussed below: Area Forecast Discussion National Weather Service Burlington VT 416 PM EST Fri Jan 1 2021 NEAR TERM /THROUGH SATURDAY NIGHT/... As of 410 PM EST Friday...The second change in the forecast concerns snow totals, mainly along the Canadian border and across the Northeast Kingdom. Snow totals are now expected in the 4 to 8-inch range across this area, the bulk of which will fall between 7 AM and 1 PM on Saturday. Localized accumulations up to 10 inches are possible across the northern Green Mountains. During this time, a band of heavier snow is possible, producing rates up to 1 inch/hour for a brief period of time. This is attributed to enhanced meteorological forcing paired with higher snow ratios as colder, drier air pushes in from the northwest. By late Saturday afternoon, all precipitation will transition to either snow or rain before coming to an end Saturday evening. Changes in their advisories maps show some Winter Storm Warnings moving into Northern Vermont, and some areas of 8-12” shading in the Northern Greens and Northeast Kingdom. Our point forecast here got a bump to roughly the 6-10” range, and I see some 6-12” forecast numbers for the higher elevations along the spine.

The latest BTV NWS maps for the upcoming storm are below. The notable change in the advisories map is the Winter Storm Warning area in NNH, and on the projected accumulations map they’ve refined it to show some areas in the 6-8” shading. The point forecast here is roughly 3-7” through Saturday, which is right in line with what the map shows.

Well, the great news is that in whatever frozen form it falls, 0.50-0.75” of L.E. would be huge for base building on natural terrain. As long as it’s topped off with a bit of lower density stuff, low-angle terrain would immediately be back in action. Checking on BTV NWS point forecasts, I see projected L.E. of 0.69” here at our site, 0.83” for Bolton, and 0.89” for Mansfield at elevation.

I got a text this afternoon indicating that we’ve been put under a Winter Weather Advisory for this upcoming system, which is substantial enough to have earned the name Winter Storm John. The BTV NWS advisories map is pretty straightforward with wall-to-wall Winter Weather Advisories throughout the north country. Our point forecast here calls for 4-8” of snow with the potential for some sleet mixed in on Saturday. The projected accumulations map looks like it’s on the lower end of that with broad areas in the 3-4” and 4-6” ranges, but the products often get synced up better as the storm gets closer.

Event totals: 0.2” Snow/0.01” L.E. We’ve had flurries/light snow on and off all day, but just an additional 10th of an inch of accumulation through noontime with some of the graupel. I haven’t seen anything accumulate this afternoon with the temperatures a few degrees above freezing – it’s been fluffy flakes that melt fairly easily relative to the graupel. Details from the 12:00 P.M. Waterbury observations: New Snow: 0.1 inches New Liquid: Trace Temperature: 36.5 F Sky: Light Snow (1-2 mm flakes) Snow at the stake: 1.0 inches

Event totals: 0.1” Snow/0.01” L.E. We had some standard flakes yesterday afternoon and last night, and I’ve seen graupel falling today, but a tenth of an inch is all I’ve observed for accumulation from this event (which appears to be the remnants of Winter Storm Ivy merging with a clipper to our north) thus far at our site. 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: 36.1 F Sky: Light Snow/Graupel Snow at the stake: 1.0 inches