J.Spin

As I did back on Saturday, I cored the snowpack at our site this morning as part of my CoCoRaHS observations to see how the snowpack changed after this most recent storm cycle. With the numbers now in, we can see that the SWE in the pack went from 1.69” before the system to 2.08” now. Snowpack depth didn’t really increase, but the SWE certainly did. Down here we picked roughly ¾” of liquid from the storm, and not all of it went into bolstering the pack since our valley temperatures were a bit marginal, but the mountains likely picked up more than an inch of liquid, and it all should have gone into enhancing the snowpack. I see that the latest report from the Mt. Mansfield Stake indicates that it’s at 48”, which is still a bit below average, but that’s a very solid addition. I think it was at about 40” before this storm? Even if that’s not a huge gain in depth, we know from being out there on the mountain and skiing it over the past few days that it was a hefty addition to the pack and a solid resurfacing up high.

Event totals: 2.6” Snow/0.73” L.E. There are actually a few flurries still around this morning, but this should be the last set of observations for this storm, and the above totals should be the final numbers of for the event. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.1 inches New Liquid: Trace Temperature: 19.3 F Sky: Partly Cloudy Snow at the stake: 7.0 inches

I was curious about how this storm has been playing out at the resorts up and down the spine, so I did the usual assembling of the north to south snow reports for an idea of the storm totals. It seems like the biggest drop off was south of Killington/Pico. The most notable buck in the trend was Bromley reporting 7” for their 72-hour total, when their very immediate neighbors Stratton and Magic are both reporting 1”: Jay Peak: 12” Smuggler’s Notch: 11” Stowe: 13” Bolton Valley: 12” Mad River Glen: 9” Sugarbush: 9” Pico: 7” Killington: 7” Okemo: 2” Bromley: 7” Magic Mountain: 1” Stratton: 1” Mount Snow: 1” It’s still snowing here at the house under the current northwest flow, so it’s possible that the resorts are picking up a bit more as well:

Event totals: 2.5” Snow/0.73” L.E. Well this is one of those storms that PF might associate with the “Energizer Bunny” term, due to the way it keeps going and going. This is the fourth day of observations for this event at our site, and indeed we’ll probably have at least one more round since it’s snowing right now. Details from the 6:00 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: 27.3 F Sky: Light Snow (1 to 2 mm flakes) Snow at the stake: 7.0 inches

Event totals: 2.3” Snow/0.72” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.6 inches New Liquid: 0.08 inches Snow/Water Ratio: 7.5 Snow Density: 13.3% H2O Temperature: 30.0 F Sky: Light Snow (1 to 2 mm flakes) Snow at the stake: 7.0 inches

Event totals: 1.7” Snow/0.60” L.E. Details from the 6:00 P.M. Waterbury observations: New Snow: 0.3 inches New Liquid: 0.04 inches Snow/Water Ratio: 7.5 Snow Density: 13.3% H2O Temperature: 33.3 F Sky: Light Snow (2 to 12 mm flakes) Snow at the stake: 7.0 inches

That’s really interesting with respect to the localization. We really didn’t know much about the upslope snows in the Whites on the forum here until Alex joined, and we’re certainly learning more about it with Diane in the area as well. We’ll have to get PF into the conversation to get his thoughts on the localization issue, but it does sound a bit more restricted over there in the Whites. As “localized” as we talk about it over here in the Greens, it’s always felt to me that it’s there pretty much up and down the entire spine, even down into SNE. It just becomes less and less intense and frequent as one heads south from the Jay Peak area at the international border. We get it to a certain distance east and west of the spine, and that depends on the Froude Numbers associated with each event, but it seems like it’s over the entire length.

Event totals: 1.4” Snow/0.49” L.E. We’ve been having on and off rounds of light snow on the back side of this system, with another batch of flakes starting up as I was leaving the house this morning. Details from the past couple rounds of observations are below, and the snow density has definitely come down some as we head into this part of the storm. Details from the 12:00 A.M. Waterbury observations: New Snow: 0.6 inches New Liquid: 0.05 inches Snow/Water Ratio: 12.0 Snow Density: 8.3% H2O Temperature: 33.1 F Sky: Cloudy Snow at the stake: 7.0 inches Details from the 6:00 A.M. Waterbury observations: New Snow: 0.2 inches New Liquid: 0.02 inches Snow/Water Ratio: 10.0 Snow Density: 10.0% H2O Temperature: 32.5 F Sky: Cloudy Snow at the stake: 7.0 inches

Yeah, that wet pack snow is very PNW-like. I’ve experienced it most intensely at Whistler Blackcomb with their relatively low base elevation. It was kind of fun today though using the end of runs to work with the boys and discuss technique. At the mountain today we typically stayed out of steep off piste areas below -2,500’ because they need just a bit more base to really be in prime form, but above that it was fantastic as you noted. We generally found 18 inches of powder up high before we’d encounter any crusty layers. Even if the 40” or so at the stake is below average, that's still a lot of snow – we could routinely stick our poles into the snowpack right up to the handle. A few shots from today’s outing:

Event totals: 0.6” Snow/0.42” L.E. Details from the 6:00 P.M. Waterbury observations: New Snow: 0.1 inches New Liquid: 0.03 inches Snow/Water Ratio: 3.3 Snow Density: 30.0% H2O Temperature: 33.4 F Sky: Light Snow (2 to 10 mm flakes) Snow at the stake: 6.5 inches We were out much of the day at the mountain, but it looks like the snowfall was fairly minimal here at the house. The flow was from the south much of the day, but I see that it’s turned more to the west now and the snowfall has really picked up with much larger flakes.

We’re on the gondola right now heading up, and the conditions at elevation are simply fantastic. Yeah it might have been only a few inches of new, but it’s on top of a LOT of great snow below it. Unsettling snow of piste is actually quite deep where it hasn’t been touched. The line where you hit that PNW-style wet pack on the groomed surfaces is right around the 2,000’ mark on this side of Mansfield based on what we experienced on our last run.

Event totals: 0.5” Snow/0.39” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: Trace New Liquid: 0.02 Temperature: 33.4 F Sky: Mostly Cloudy Snow at the stake: 7.0 inches

Well, the projected snowfall numbers in the Mansfield point forecast through Monday night are certainly nothing to scoff at – even the low end of those accumulations would be a solid addition: Overnight Snow, mainly before 4am. Low around 27. Windy, with a south wind 27 to 32 mph decreasing to 17 to 22 mph. Chance of precipitation is 90%. Total nighttime snow accumulation of 3 to 5 inches possible. Sunday A chance of snow before 7am, then a chance of snow showers after 7am. Cloudy, with a high near 28. Breezy, with a west wind 15 to 23 mph. Chance of precipitation is 50%. New snow accumulation of 1 to 2 inches possible. Sunday Night Snow showers. Low around 21. Windy, with a west wind 25 to 31 mph. Chance of precipitation is 80%. New snow accumulation of 2 to 4 inches possible. Monday Snow showers. High near 26. Windy, with a west wind 22 to 26 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 3 inches possible. Monday Night A 50 percent chance of snow showers. Cloudy, with a low around 17. Windy, with a northwest wind 22 to 31 mph. New snow accumulation of 1 to 3 inches possible.

Event totals: 0.5” Snow/0.37” L.E. Details from the 12:00 A.M. Waterbury observations: New Snow: 0.3 inches New Liquid: 0.17 inches Snow/Water Ratio: 1.8 Snow Density: 56.7% H2O Temperature: 32.9 F Sky: Snow (2 to 20 mm flakes) Snow at the stake: 7.0 inches Since it changed over from sleet in the afternoon, the precipitation has been all snow this evening. At times the flakes have been small, but the heavier echoes bring big aggregates. Accumulations have been very waterlogged and sloppy with temperatures around the freezing mark.

Event totals: 0.2” Snow/0.07” L.E. Details from the 6:00 P.M. Waterbury observations: New Snow: 0.2 inches New Liquid: 0.03 inches Snow/Water Ratio: 6.7 Snow Density: 15.0% H2O Temperature: 34.7 F Sky: Light Snow (2 to 4 mm flakes) Snow at the stake: 7.0 inches As I mentioned in my previous post, the precipitation started as sleet here back around 3:00 P.M. At that point the temperature was up around 37 F, and it’s been falling through the evening. Snow began mixing in at some point, and then that became the predominant precipitation type. Temperatures are still above freezing thought, so accumulation has been fairly slow.

I was just outside and we’ve got some sleet falling here at the house.

I’d noted your comment about the net gain for the snowpack, and indeed it looks like this system should be another net gain even down here in the valley. I had time to core the snowpack this morning here at our site to get an idea of where it stands, and found that it currently contains 1.69” of liquid. I checked on the NOHRSC modeling for our site, and the modeling’s done quite well over the past 12 days since I last did a snowpack core. Their modeled value for snowpack SWE at our site today was ~1.63” of liquid before I put in my data this morning, which is just a few % difference from the actual analysis and I’m sure easily within the variability in my sampling. We’ve had over 18 inches of snowfall and 1.26” of liquid during that intervening period, and the modeling really incorporated that into the snowpack well. I just refreshed the NOHRSC snow depth/SWE/snow density modeling plot for our site, and I’ve added it below. I was surprised to see that they’ve already incorporated (or at least plotted) my data from this morning (the most recent SWE and snow depth points), so that was quick. The modeling indicates that the snowpack is expected to go up to ~2” SWE, then drop back down a bit to the 1.8” to 1.9” range. The modeling doesn’t yet go out to incorporate any backside snows, so we’ll see how that plays out. If it turns out to be the typical backside type of snow it will potentially add a bit of SWE to the snowpack, but it’s usually more notable for adding snow depth.

I got an alert yesterday from the BTV NWS that we’re under a Winter Weather Advisory in association with this next storm. The advisory is for mixed precipitation, and presumably in place for any potential ice because snow accumulations are expected to be fairly minimal. There is some additional snow expected on the back side of this system, but the current projected accumulations map only covers through 7:00 P.M. tomorrow, so it doesn’t include those potential accumulations.

LOL, just have them recruit students from chemical/biomedical graduate programs. We literally train for decades to make meticulous observations, manipulate small samples, and measure them with accuracy and precision. I guess all you have to do is somehow get them interested in snow.

I’m passing along a conditions update and a few shots from this weekend’s skiing at Bolton. We were out on the backcountry network on Saturday, and then we went for lift-served skiing on Sunday. Despite the fact that that the Mt. Mansfield Stake has hit 40” (a common threshold for most standard off piste skiing to be ready around here) and is getting close to average depth for this time of year, Bolton is lagging behind that benchmark a bit. I think it’s because the thaw cycling hit them pretty hard in areas below 2,500’ or so – the base coverage down at those elevations seems like it was patchy after that last warm storm system. The Timberline area covering the 1,500 – 2,500’ elevation band is only marginally open, and even Cobrass (which faces south in some key spots) off the summit wasn’t open. We actually had some fantastic runs in the trees on Sunday, because some areas we encountered (like the Preacher Woods and Cobrass Woods) were in nice shape, but it’s still very inconsistent. Areas that already had great base coverage offered fantastic turns this weekend thanks to the new snow, and areas that were borderline were pushed to that next level. So the dense snow from Winter Storm Jacob was obviously a huge help, but I’d say they still need another inch or two of liquid equivalent to really get close to 100% open.

It was a solid week here at the house as well; we had 18.1” snow/1.20” L.E. between the four storms. That was definitely the best week of the month in terms of snowfall. This next week doesn’t look as productive though; it looks quieter than average for the midweek. Our CoCoRaHS numbers for the month thus far are 33.5” snow/3.20” L.E., so it’s certainly not last January where we’d hit 50” at this point, but at least it’s moving along decently with the final third to go.

Final totals at our site for this storm were 6.0” Snow/0.43” L.E.

Event totals: 6.0” Snow/0.43” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.2 inches New Liquid: Trace Temperature: 5.4 F Sky: Mostly Clear Snow at the stake: 11.0 inches We’ve mostly cleared out now, so the totals above should represent the final numbers for Winter Storm Jacob here at our site. With 6.0” of snow accumulation we just barely hit the bottom of the 6-12” range that was in out point forecast, but that’s sometimes the way it goes with these SWFE-type events. Indeed, roughly 2/3 of the liquid from this storm came with a fairly dense 8.6 to 1 snow to water ratio.

Event totals: 5.8” Snow/0.43” L.E. Details from the 9:00 P.M. Waterbury observations: New Snow: 0.7 inches New Liquid: 0.01 inches Snow/Water Ratio: 70.0 Snow Density: 1.4% H2O Temperature: 13.6 F Sky: Light Snow (1 to 4 mm flakes) Snow at the stake: 11.0 inches

Event totals: 5.1” Snow/0.42” L.E. Details from the 12:00 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: 21.4 F Sky: Light Snow (2 to 7 mm flakes) Snow at the stake: 11.5 inches