J.Spin

It was just cloudy here earlier, but snow began to fall around 8:10 A.M. as moisture starts to push into the area:

Event totals: 2.0” Snow/0.12” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 0.1 inches New Liquid: Trace Temperature: 25.7 F Sky: Cloudy Snow at the stake: 6.0 inches The overnight snow should make the end of the effects of yesterday’s low pressure system. Next up is the potential snow from the strong arctic cold front coming through the area.

I just ran the numbers using my data, and starting the winter snowpack here from this date (Nov 20th) would be fairly common – this would be 3 times in 13 years of data, so that’s once every 4 or 5 years. Note though, the current snowpack started on Nov 10th, and if that holds it would be 1.67 S.D. ahead of the mean. That should only happen about once every 20 years, but we’re probably getting just about “due” for one of these as the data set grows. Those numbers are for here along the spine of the Greens though, so the occurrence might be a bit less around here away from the spine. The thing is, if those are the odds here, the percent of seasons where the winter snowpack starts this early in areas farther south out of the mountains must be very small.

Event totals: 1.9” Snow/0.12” L.E. The forecast for today was 1-2” with this current event, so I’d say we’ve hit that with some light snow continuing. Projected accumulations for tomorrow are similar with the anticipated cold front. Details from the 8:00 P.M. Waterbury observations: New Snow: 1.9 inches New Liquid: 0.12 inches Snow/Water Ratio: 15.8 Snow Density: 6.3% H2O Temperature: 25.7 F Sky: Light Snow (2-8 mm flakes) Snow at the stake: 6.5 inches

Snow started up around 8:15 A.M. at our site, with flakes in the 2-3 mm range. The forecast is calling for 1-2” today with the low pressure passing through the Mid-Atlantic States into Southern New England. The forecast also indicates the potential for additional snow tomorrow, with the sharp cold front coming through the area.

Nice stuff PF – indeed those are some of the easiest glades to get rolling in the early season; there’s generally nothing overly aggressive with respect to obstacles, and lower slope angle means even high speed lift-served skier traffic levels aren’t going to be tearing away the snow cover too quickly. From what I’ve seen, those glades are typically well in play by the time the stake has hit the 24” mark, unless the snow is total fluff or the snowfall has been extremely elevation dependent. I jumped into the trees for a bit at Bolton Valley yesterday on moderate-angle terrain at around 2,300’, and with probably 20 inches of reasonably dense snowpack topped with powder, there were certainly no issues. More things are in play/sustainable of course when it’s only non-lift-served skier traffic. I’m actually curious to see what the stake has got for snowpack, since it was last at 19” but hasn’t been updated for a couple of days. That is about a foot above average for this time of year though.

Bolton Valley had quite a multitude of recreational visitors this weekend, which isn’t too surprising with 36 inches of snow reported in the past week. We had a couple of outings, so I can pass along some snow updates and photos. On Saturday we were at Timberline most of the time, and snow depths in the 1,500’ – 2,500’ elevation range were typically 1 to 2 feet. The freezing level rose up to roughly 2,000’ during the warm part of Saturday, so the snow below that elevation did thicken up a bit, but even down there the powder remained manageable. The snow above that level was excellent of course. The mountain picked up another 2-3” of fluffy powder for Sunday, and I toured at to the main mountain to stay above 2,000’ in the best snow. Depth checks around the base area elevations of ~2,000’ revealed about 16 to 20 inches of snow. Indeed the powder was fantastic up in those elevations, with the new fluff on top of everything being well preserved below it. With all the activity from visitors, the main mountain was a veritable superhighway of skin tracks that would take you essentially anywhere you wanted to go fairly easily. Full reports are linked above, but here are a few pictures from the weekend:

I don’t have data for other areas of the Northeast, but tree skiing in November is actually rather common in the Northern Greens. It starts in November in about ¼ (26.3%) of seasons. Once the snowpack at the Mt. Mansfield Stake hits roughly 24 inches, that’s about the time you’ll find people starting to ski the trees around here (mean start date is Dec 12th ± 19 days). I ran an analysis several years back in which I compared that 24” number to actual empirical online reports of people tree skiing, and it lined up fairly well. Using 24” is not overly aggressive (you’ll find people who will venture in before that), and it’s not as conservative at the 40” rule, it’s more of a decent measure of when semi-conservative folks will start venturing into appropriately maintained areas. Early season snowpack here can sometimes start as a lot of fluff (which means more than 24” may required for tree skiing) or dense snow (where less than 24” can suffice), so the 24” value is going to be an average of those possibilities. I’m not even sure if the stake has hit the 24” mark yet this season (the most recent report I’ve seen is 19”), so this is a great example of a season below that threshold because of the dense snowfall we’ve seen. Having the tree skiing around here start this early in November is a bit less common, it happens in about 10% of seasons. The updated plot (through 2017-2018) for the date of reaching 24” at the stake is posted below, which shows the number of times and dates in the past 60 years or so when tree skiing would have started in November.

Event totals: 1.8” Snow/0.09” L.E. It looks like the upper level shortwave and secondary cold front have passed through the area now, so that should be it for that event. The next potential windows for snow in the area appear to be on Monday/Tuesday and then again on Thursday. 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: 19.2 F Sky: Partly Cloudy Snow at the stake: 7.5 inches

Event totals: 1.2” Snow/0.08” L.E. This evening’s snow has certainly got some loft to it thanks to some big flakes – snow to liquid ratio is up near 20 to 1. Details from the 8:00 P.M. Waterbury observations: New Snow: 1.1 inches New Liquid: 0.06 inches Snow/Water Ratio: 18.3 Snow Density: 5.5% H2O Temperature: 32.7 F Sky: Light Snow (2-6 mm flakes) Snow at the stake: 7.5 inches

We picked up a tenth of an inch of snow earlier this morning, but it was too warm to accumulate much else today. This evening’s snowfall is much more robust though, so we’re certainly picking up some accumulation now. You can see more of those 30 db echoes crashing into the spine:

Indeed, the BTV NWS mentioned it in their discussion as well. We’ve had on and off light snow shower activity here at the house, but it’s picking up now with some additional moisture coming into the area:

Event totals: 1.6” Snow/0.13” L.E. Well, the BTV NWS is attributing this afternoon/evening’s snow to a specific upper level shortwave/trough, and indeed there was a defined break in the snowfall, so I guess it’s best to split it out from Winter Storm Avery. 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: 32.9 F Sky: Flurries Snow at the stake: 10.5 inches

Yeah, hopefully there are many more right side up storms to come. Analyses for this storm were: 10.2 to 1 for the overnight initial burst 13.3 to 1 for the morning push of moisture back to the east 12.5 to 1 for the afternoon snow through 6:00 P.M. We’ve had a bit more this evening, so if I’m up I’ll do a midnight analysis, or if I’m not I’ll just run it tomorrow morning. There does appear to be another shot of moisture upstream on the regional radar, so we’ll see if that delivers anything here. It looks like it might be compliments of our good friend Lake Ontario: .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... As of 939 PM EST Friday...The trends continue as mentioned earlier. The snow shower activity associated with elongated shortwave has lifted NE and now broad SW flow across Lake Ontario bringing some additional snow showers for Adirondacks and Northern Greens for the overnight. No changes to forecast.

Event totals: 8.2” Snow/0.72” L.E. This evening coming home from Burlington was one of those drives where the snow just kept ramping up in intensity the farther you headed into the mountains. At the moment the snowfall seems to be running at about ½”/hr. here. Details from the 6:00 P.M. Waterbury observations: New Snow: 1.0 inches New Liquid: 0.08 inches Snow/Water Ratio: 12.5 Snow Density: 8.0% H2O Temperature: 31.8 F Sky: Snow (2-8 mm flakes) Snow at the stake: 10.0 inches

Yeah, that’s going to be horribly inaccurate unless they update it tomorrow morning – we’ve had over 8 inches now, but even as of just noontime today we’d added substantially more snow than what came in that initial overnight burst.

Event totals: 7.2” Snow/0.64” L.E. Snowfall here at the house was 4.4” with the initial overnight burst of precipitation and then another 2.8” fell when the precipitation moved back through. We’re into the backside precipitation now, and I’ll take the next set of observations at 6:00 P.M. to update on how this part of the storm is going. Details from the 12:00 P.M. Waterbury observations: New Snow: 2.8 inches New Liquid: 0.21 inches Snow/Water Ratio: 13.3 Snow Density: 7.5% H2O Temperature: 33.1 F Sky: Cloudy Snow at the stake: 9.0 inches

Snow has started back up here in Burlington, and from the radar it looks like the next block of moisture we’re been hearing about is just heading into the area. Hopefully the Greens will do their usual job of wringing out some of that available moisture.

Snowfall was light and flake size was small as I headed west from Waterbury this morning, and it stayed that way as I continued toward the Champlain Valley up until I hit Williston. At that point the flakes got larger (10-15 mm) and intensity increased. Visibility was still in the ½ to ¼ mile range, so nothing outrageous, but a definite bump up from farther east. There’s a steady snow here in Burlington now, and it looks like the snow is pushing back to the east now based on the radar: Road conditions were fine this morning, snow-packed on Route 2 and black tire lanes on I-89. I didn’t see any accidents so it looks like it was experienced Vermonters driving the way experienced winter drivers do.

Below I’ve added the latest projected accumulations map from the BTV NWS. They talk about the mesoband hitting the Champlain Valley in their discussion, so the updated totals seem to reflect that. Here at the house our most recent overnight forecasts were 3-5” and then 4-8”, and both were good estimates of what we received.

Event totals: 4.4” Snow/0.43” L.E. Details from the 6:00 A.M. Waterbury observations: New Snow: 4.4 inches New Liquid: 0.43 inches Snow/Water Ratio: 10.2 Snow Density: 9.8% H2O Temperature: 24.4 F Sky: Snow (1-10 mm flakes) Snow at the stake: 7.0 inches

The BTV NWS mentioned in their discussion that they did a bit of an update in their projected accumulations map, so that’s added below. Their latest thoughts have a general 8-12” stripe along the spine of the Greens.

I just checked out the BTV NWS map updates, and as they often do, they’ve slowly ratcheted things up as the storm gets closer and confidence builds. The projected accumulations were bumped up a notch, apparently enough that it nudged most areas into Winter Storm Warning criteria, so those have expanded to a lot of the area. For our site, the point forecast is in the 6-12” range through Friday night, and as PF has been saying (and the BTV NWS forecast discussion notes as well), getting up into the higher end of that range would probably depend on getting into some banding.

The BTV NWS updated their maps for Winter Storm Avery overnight. The main changes were to put some areas into Winter Storm Warnings, and most of VT was bumped to the 6-8” bracket on the expected snowfall map.