J.Spin

Event totals: 0.1” Snow/Trace L.E. I didn’t think snow was going to start up around here until a bit later in the day, but there was already some accumulations on the boards this morning with light snow in the air. The BTV NWS discussion indicates this event is coming together around here through a collection of factors, such as low pressure moving through Quebec, the presence of LES moisture, snow squalls from the passage of the cold front, and a trailing shortwave. The snowfall has not been consistent the whole time this morning – there are points where it’s snowing lightly, but blue sky is also visible. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.1 inches New Liquid: Trace Temperature: 25.7 F Sky: Light Snow (2-12 mm flakes) Snow at the stake: 15.0 inches

This morning we headed out to the hill to check out the snow from Winter Storm Oaklee. Having clear skies, comfortable winter temperatures, and about a foot of fresh snow held the potential for some great skiing. As noted in observations here in the thread, the storm cycle progressed into some impressive 2-4% H2O champagne, and indeed what we found out there at Bolton was some very high quality powder. The denser (~10% H2O) snow from the front end of the storm cycle wasn’t too evident underfoot actually, so the only major downside of today’s powder skiing was that it wasn’t quite bottomless. Depending on the pitch, you were certainly touching down on the subsurface, but on everything except for the steepest terrain, the powder turns were quite good. On moderate angle terrain you could typically get by with 80-90% bottomless skiing, and because the powder was just so incredibly dry, you could ride it on lower angle terrain and it skied really well because of such low impedance. Measurements throughout the morning revealed plenty of 8-12” powder depths, and we just ended up staying down at Timberline for our entire session because there was rarely a lift queue of note. A lot of trails weren’t open simply because the headwalls didn’t have quite enough snow to cover them up fully, but routes were available to traverse below them, and all that terrain was just loaded with quality powder. We generally stayed on piste because there was plenty of powder available there, and it was the better option anyway. Some off piste areas are dicey because of the recent warmth, but the off piste areas that are typically protected from the warmth and are well manicured were in great shape, so we did have some nice turns in those spots. A few shots from today’s outing:

Below is the north to south listing of available snowfall totals from the Vermont ski areas for Winter Storm Oaklee. It looks like the numbers are a bit lower down to the south, perhaps due to the increased snow ratios that appeared with the latter part of the storm up north. Jay Peak: 16” Burke: 8” Smuggler’s Notch: 13” Stowe: 10” Bolton Valley: 11” Mad River Glen: 15” Sugarbush: 12” Middlebury: 12” Suicide Six: 10” Ski Quechee: 12” Pico: 9” Killington: 9” Okemo: 7” Bromley: 10” Magic Mountain: 8” Stratton: 9” Mount Snow: 9”

It actually looks like there’s a bit of NNE bread and butter style pattern setting up on the heels of Winter Storm Oaklee. Next up in the storm queue appears to be a low pressure system moving through Quebec tonight and coming into the area tomorrow afternoon, with squalls and a reinforcing shortwave. The forecast suggests accumulations of 1-3” around the area. After that, there’s a clipper-type system shown in the models for Tuesday night into Wednesday. The BTV NWS mentions the next potential system for Wednesday night into Thursday as part of their discussion, but they say that one lacks upper level support and would probably only be flurries or a dusting. Some of the models do more with it though, so it’s certainly something to keep an eye on. Then, the models are showing possibility for next weekend, but the suggestions right now would be for a larger system that might be associated with some warm air, so not really a northern stream bread and butter type system. Still, that’s four potential systems in about a week, so there’s a lot of potential in the immediate future.

That’s great to hear about the snowboard and getting in some 6-hour collection intervals for the storm. It seems like your accumulation numbers were right on track with what I was getting here. Now all you need to do is join CoCoRaHS, and start getting accumulation cores so you can report liquid. Just ask Ginx, he’s a big advocate for getting people join. Plenty of people just get snow depths though and don’t necessarily do cores for winter storms. CoCoRaHS had sent me a couple of extra Stratus gauges for backup/replacement, so my wife took one of those and now reports from her school site in Morrisville with her first grade class. Her students had been doing daily weather observations for years, but now they get to work on their numbers as part of their daily weather routine with the liquid from the gauge.

Event totals: 12.0” Snow/0.65” L.E. The skies cleared out overnight, so that marks the end of Winter Storm Oaklee, and the above totals are the final numbers for here at our site. The total liquid picked up here was right in line with the modeling consensus, and kudos to the BTV NWS for their usual great forecasting – their 8-12” range that was forecast in this area was right on track. With the given liquid, those higher snow ratios were required to get into that accumulation range, but those ratios went way up as the storm progressed. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.4 inches New Liquid: 0.01 inches Snow/Water Ratio: 40.0 Snow Density: 2.5% H2O Temperature: -2.4 F Sky: Mostly Clear Snow at the stake: 17.0 inches

Event totals: 11.6” Snow/0.64” L.E. Details from the 6:00 P.M. Waterbury observations: New Snow: 6.9 inches New Liquid: 0.22 inches Snow/Water Ratio: 31.4 Snow Density: 3.2% H2O Temperature: 12.4 F Sky: Snow (5-20 mm flakes) Snow at the stake: 18.0 inches

Event totals: 4.7” Snow/0.42” L.E. This morning’s snow was down slightly in density to 8.6% (11.6:1) from the 9.4% (10.6:1) obtained for the overnight collection. Details from the 12:00 P.M. Waterbury observations: New Snow: 2.9 inches New Liquid: 0.25 inches Snow/Water Ratio: 11.6 Snow Density: 8.6% H2O Temperature: 21.6 F Sky: Snow (5-10 mm flakes) Snow at the stake: 12.5 inches

Yeah, the afternoon was solid here at the house as well – 5 to 6” in the 12:00 P.M. to 3:00 P.M. period, so certainly up there in that 1.5-2”/hr. range. The snow ratios are much higher now, and that will easily allow folks to get those ~10” numbers that the BTV NWS had in their Event Total Snowfall map. We’ve already sailed right past that here at our site thanks to the ratios. I think the biggest ratios will be from this afternoon, but I’ll see what the ratio was on the morning’s accumulation and how it compared to the overnight accumulation.

There might be a bit of that going on up north here as well. I left home with decent snowfall, and that lasted westward through to about Bolton, then it really tapered down to lighter snow as I passed through the western slopes. Accumulation in that area were also somewhat lower, with what looked like an inch or so. Then as I continued westward toward the Champlain Valley, snowfall intensity was back up, and accumulations seemed to be back up in that 4” range. I did pass through some louder snow on I-89 in Williston – it was never sleet by the sounds I heard, it made the sound of graupel, so I just figured there was some variations going on at various levels in the atmosphere.

October through February for our site averages 20.23” of liquid, and this season we’ve seen 20.14” of total liquid with a few days of February to go. Looking at the individual months, December and January were drier than average, so if that liquid trend has been the same for the mountains, perhaps it’s part of the issue. Our December and January snowfall were both below average here, so perhaps that was part of the issue for the mountains, but so far, it’s not been enough to get us beyond 1 S.D. from our mean cumulative season snowfall here in the valley. October: 5.57” vs. 5.31” mean November: 5.59” vs. 3.94” mean December: 3.28” vs 4.46” mean January: 1.95” vs. 3.30” mean February: 3.75” vs. 3.23” mean February is only to date, so that’s going to go up with the contribution from the current system.

Oh, I see it now that I’ve checked out the rest of the map details – I saw that it was the same time of issuance, but they’ve modified the period that is covered on the map.

As noted in my observations, the morning ratio here was 10.6 to 1, so assuming L.E. of ~0.6”, staying at that ratio would provide something in the 6-7” range for snow accumulations around here. Accumulations in the 10” range will require more moisture (some models have that) or higher ratios, but putting down ~0.6” of L.E. into the snowpack in the form of snow is great, regardless of how it actually stacks up. In terms of the latest BTV NWS maps, it’s wall-to-wall Winter Storm Warnings on the advisories map, and interestingly, the Event Total Snowfall Map I get from the site actually has slightly different numbers than the one you posted. I’m not sure what causes that difference.

Event totals: 1.8” Snow/0.17” L.E. Snow was quite heavy at observations time this morning; certainly in the 1”/hour range or so, but it hasn’t been that way the whole time and there have been periods with less intensity as well. Snow density came in just a bit under the standard 10% mark – 9.4% H2O, or 10.6 to 1 in terms of ratio. Details from the 6:00 A.M. Waterbury observations: New Snow: 1.8 inches New Liquid: 0.17 inches Snow/Water Ratio: 10.6 Snow Density: 9.4% H2O Temperature: 13.6 F Sky: Heavy Snow (3-10 mm flakes) Snow at the stake: 9.5 inches

A quick look at liquid for the latest runs shows most of the models having our area in the 0.50” – 0.75” L.E. bracket, with some of the mesoscale models getting us into the 0.75” – 1.00” bracket, and there are a couple models with the area in the 0.4” – 0.5” L.E. bracket. The CMC was one of those with that lower L.E., but it’s more recently come up to match the other models in that next bracket. We’re a bit south of PF, but our point forecast has ~0.6” of L.E. here at our site, and that seems very consistent with the modeling. That would be 6” at a 1:10 ratio, or 12” at a 1:20 ratio. Our point snowfall forecast sums to 8-12” through Friday night, which may be a bit on the higher side, but they do mention those mid to upper level vortices that I’ve seen PF talking about having the potential to move over the area: Area Forecast Discussion National Weather Service Burlington VT 635 PM EST Thu Feb 24 2022 NEAR TERM /THROUGH FRIDAY NIGHT/…potent embedded 700 to 500mb vort, which wl move directly acrs our cwa btwn 15z-21z Friday, resulting in a period of moderate to heavy snowfall. HREF shows 1 to 2 inch per hour rates with pockets of up to 2.5 inches per hour over the dacks around 18z Friday, which looks reasonable given the idea of strong dynamics and deep moisture within the DGZ. Fluff factor could result in some areas overachieving, but limiting factor wl be extremely quick movement of system, with favorable dynamics/lift and moisture only lasting for 3 to 6 hours from west to east acrs our fa. Our point forecast does have that “heavy snow” listed for the Friday period, so there’s enough confidence to get that put in there. And hey, it’s the Northern Greens, so there’s always the potential for a little extra oomph if things line up to let the orographics help with a touch of extra lift. And as PF said, if dendritic growth isn’t great and it’s tiny flakes, the accumulations will be on the lower side. But who really cares about the exact accumulations numbers aside from the record keeping aspect, it’s the L.E. that matters around here; that’s what’s going to make the difference on the slopes. The current snowpack needs a major resurfacing; that’s all there is to it, so that means getting down as much L.E. as possible. Dense snow might in fact be better than champagne in terms of the resurfacing anyway. Modeling suggests that there are more potential shots of snow over the next week as well, so perhaps we’ll do a little catching up on seasonal snowfall with respect to average.

Seeing the data from regional sites is very interesting, because at our site this has most definitely not been a bottom of the barrel winter up to this point. Even in our small data set of 14 seasons, there are three seasons with less cumulative snowfall up to this point, three seasons with lower snowpack on this date, and both of those parameters for this season are currently within 1 σ of the mean. We’ve had two storms of 16”+, which is already average for an entire season in that regard. The Mansfield snowpack data clearly indicate that the mountains are well off the usual mark in terms of snowpack. I think the same thing happened last year, where the mountains were much farther below average on snowfall/snowpack than the valleys? We actually ended last season with roughly average snowfall at our site, or even slightly above. One would think that the mountains should have lower standard deviation and have higher snowpack/snowfall reliability, but perhaps not? What sort of seasonal weather pattern/trend has to come together to keep the valleys closer to average than the higher elevations?

Event totals: 1.2” Snow/0.44” L.E. We’ve mostly cleared out, so the above totals should be the final numbers for Winter Storm Nancy at our site. As others in the thread noted, the back side snow was surprisingly impactful for travel, and that impact is notable when one realizes that there were just a couple hundredths of an inch of liquid in there. I did see some coatings still on the roads this morning, but much more impactful was the effect those big, fluffy flakes had on visibility. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.6 inches New Liquid: 0.01 inches Snow/Water Ratio: 60.0 Snow Density: 1.7% H2O Temperature: 8.6 F Sky: Mostly Clear Snow at the stake: 8.0 inches

You know I’d be the first to point out if you seemed to be overreacting to apparently unusual winter conditions for your area, but let me split it up between snowpack, and the running total for season snowfall. In terms of season snowfall, we’re certainly behind average pace here at our site (91.6” to date vs. 114.5” for the mean) but it’s still well within 1 σ (31.0”), and I suspect you’re within 1 σ at your site as well. So, sure, we’re behind average pace, but the stats say it’s no big deal. But in terms of your snowpack, I can’t imagine how the current depth is anything but outrageously abnormal. We had 3.5” of liquid equivalent in the snowpack here before that first storm, and you had even more than that. That amount of liquid should typically be enough to survive even two or three of those types of warm sector events, as I mentioned in my post a while back, and this current system wasn’t even that potent. The reason that the disappearance of the snowpack at your site is so weird is that it really should be baked into the climatological record for your area, so if south winds beat up the snowpack like that, then there should be plenty of times during the winter where it disappears. The mean snowpack depth for this date at our site is 16.8”, so it’s probably in the range of 2 feet at your site. Unless your neighbor’s climate is notably different than yours because of protection from winds or whatever (I haven’t checked the data from that site, but we could determine average snowpack for this date), it’s definitely weird that so much liquid equivalent could disappear like that.

Event totals: 0.6” Snow/0.43” L.E. Some models have been showing back side snow in our area from Winter Storm Nancy, but the signal wasn’t all that strong, so I hadn’t given it too much thought. It definitely caught my attention this afternoon though. There were a few flakes falling here and there in Burlington, but as I headed home westward into the mountains, the precipitation ramped up steadily. Accumulations began to appear on the roads around Williston, and by the time I reached the Bolton area I encountered near whiteout conditions with snow-packed roads. Here at the house, the intensity of the snow was enough that I had to put it down as “heavy snow”, since it was in excess of 1-2”/hr. while I was out making the 6:00 P.M. observations. Details from the 6:00 P.M. Waterbury observations: New Snow: 0.6 inches New Liquid: 0.01 inches Snow/Water Ratio: 60.0 Snow Density: 1.7% H2O Temperature: 24.1 F Sky: Heavy Snow (2-15 mm flakes) Snow at the stake: 8.0 inches

I got a phone alert early this morning that Winter Storm Watches are up in the area. The latest BTV NWS maps are below, and the alerts map is an interesting mix of colors that I don’t think we see very often with those Wind Advisories mixed in. The watch text indicates that a general 6-12” of snow accumulation is expected at this stage, and that fits with what’s shown in current Event Total Snowfall map.

Event totals: 2.5” Snow/0.11” L.E. The skies have fully cleared out, so the above totals will be the final numbers for this storm. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.3 inches New Liquid: 0.02 inches Snow/Water Ratio: 15.0 Snow Density: 6.7% H2O Temperature: 13.3 F Sky: Clear Snow at the stake: 11.5 inches

Event totals: 2.2” Snow/0.09” L.E. Details from the 6:00 P.M. Waterbury observations: New Snow: 0.4 inches New Liquid: 0.01 inches Snow/Water Ratio: 40.0 Snow Density: 2.5% H2O Temperature: 22.1 F Sky: Cloudy Snow at the stake: 11.5 inches

Event totals: 1.8” Snow/0.08” L.E. Details from the 12:00 P.M. Waterbury observations: New Snow: 1.8 inches New Liquid: 0.08 inches Snow/Water Ratio: 22.5 Snow Density: 4.4% H2O Temperature: 27.1 F Sky: Flurries Snow at the stake: 12.0 inches

We’ve been running at a bit over an inch per hour here since the flakes first appeared, and that includes the initial ramp up time. You guys up there are surely even above that based on the radar.

I see that snow has started up here at our site in association with this next system moving into the area.