The last snowstorm of the 2012-2013 winter season extended all the way out to Memorial Day weekend to produce some great late season skiing, but now that we’re well into summer and all the snow has melted, we can look back at how the winter went down at our location in Vermont’s Winooski Valley. The main focus in the seasonal analysis below is on snowfall, but snowpack and temperatures will be discussed as well. In this post I’ve hit on some of the highlights that came out of the data, and attached our various plots and graphs, but to get to the full data set, you can use the following link:
Thankfully, this past season’s snowfall (144.2”) marked a notable increase over the previous season (115.3”), but the total snowfall for 2012-2013 was still less than 90% of average, so that’s not likely to lift the season into the category of “great” winters. In addition, the amount of snow on the ground at the house last season didn’t help to improve the winter’s standing. Using the value of snow depth days as an integrative way of representing the season’s snowpack, one finds the 2012-2013 winter season producing a value of 729 inch-days, less than half the average value, and right down there in the basement with the well below average 2011-2012 season (688 inch-days). And, if the overall snowpack depth hadn’t already undermined any chances of redemption to an average level, the 2012-2013 snowpack secured the season’s ignominy by reaching the lowest value we’ve seen in January and February (3.0”), and coming within a hair’s breadth of melting out in the area around our measurement stake at a record early date in mid March:
Often, each month of the winter/snowfall season has its own unique flavor with respect to the weather, so one method I like to use to get a feel for the winter is to look at it on a month-by-month basis. Again, the focus below is on snowfall at our location, but snowpack is also considered, as well as mountain snowfall/snowpack and the associated effect on the local skiing. I’ll have a separate 2012-2013 ski season summary coming up, so I’ve kept the ski discussion minimal here in anticipation of a more thorough discussion in that report. The month’s total snowfall is listed at the start of each section below for reference:
Snowfall: 0.1” – October snowfall isn’t reliable enough down at our elevation to be factored much into the seasonal assessment, but this October was on the weak side, with just a tenth of an inch of snow, vs. the mean of roughly an inch. One small feather in the cap of 2012-2013 is the fact that the first accumulating snow fell on October 12th, which beats out 2010-2011’s October 15th snowfall by three days, and now represents the earliest measurable snowfall I’ve recorded here at the house since I started monitoring the weather in 2006.
Snowfall: 6.3” – November snowfall came in just a bit below average this past season, so certainly not remarkable, but notable in that it was probably about as average a November as we’ve seen. November has typically been feast or famine when it comes to snow. We actually had a total of five snowstorms in November, but a small to moderate storm of 4.4” at the end of the month contributed the bulk of the monthly total as well as some of the first great skiing of the season in the mountains.
Snowfall: 49.5” – December held the first lengthy, redeeming snowfall period of 2012-2013. Although the first half of the month was extremely poor on snowfall (just 2.2” of snow at the house), from the 16th of December onward, temperatures got cold and snow came in for a dramatic change; close to 50” of snow fell on us in the second half of the month, and as a whole the month actually wound up several inches above average. We received our second (15.5”) and fourth (11.7”) largest storms of the season during that stretch, right near Christmas and just a few days apart, so needless to say, the snow was there to set quite the holiday mood in the valleys and up above on the slopes.
Snowfall: 21.9” – January continued that good, snowy weather pattern in its first week, albeit to a lesser degree than December, but unfortunately that modest first week ultimately wound up representing roughly half of the month’s snowfall. The second week featured a couple of substantial thaws with no measurable snow, and in fact we received no accumulating snow at all for the period between January 7th and 16th, a very long stretch for the mountainous areas of Northern Vermont during the winter. The third week of January offered just a few small systems, and the fourth week was arctic cold with minimal snow. The final week attempted to recoup the losses with a modest half foot storm, but it was too little too late – the month ended with just 21.9” of snow, by far the lowest January in my records. The combination of very low snowfall and two January thaws was very deleterious to the valley snowpack – after coming down from the depths achieved in December, the snowpack depth at our location never even reached 10 inches again during the month, and got as low as 3.0 inches. That is ridiculously close to losing the winter snowpack in January, definitely the closest we’ve come based on my records since 2006.
Snowfall: 31.4” – February was again below average in snowfall, partly due to the continuation of the dry arctic pattern in the first week, and it wound up missing the mark for the lowest February in my data set by less than an inch. Although that persistent dry pattern didn’t make for a very snowy first half of the month, our third largest storm of the season (12.6”) hit in the second week. It was still a rather modest storm, but at least it did break that one foot mark for accumulation at the house. By the end of the third week of February, the snow depth at the Mt. Mansfield stake actually poked above average for the first time in about a month and a half – but it was only by a couple of inches, and it quickly went back below average as the snowpack sat there essentially stagnant for an entire month. On February 21st, the snowpack was at 65”, and roughly a month later on March 18th, it was still at 65”, without any major consolidation of more than a few inches. That’s stagnant. Our snowpack at the house languished similarly, never even getting above 10 inches of depth during that stretch – and that’s a time of year when it is usually building to its peak of the season. The carryover of the low snowpack from January also set the lowest mark (3.0”) for snowpack that we’ve ever seen in February.
Snowfall: 30.8” – Although certainly not approaching what we saw in the second half of December, the last part of the winter/snowfall season was the other relatively bright spot to mention. This was aided by our largest storm of the season, which delivered 21.3” during the last third of the month. That storm was the only real standout for the month however. It did bring March above average in terms of snowfall, but only by roughly six inches, and the resulting monthly total really ranks in the middle of the pack for Marches in my records. The fact that the snowpack in the area around our snow measurement stake at the house was barely hanging on around mid month was certainly disconcerting, but the snowpack did recover somewhat with the help of a modest mid-month storm, that big storm at the end of the month, and reasonably cool temperatures.
Snowfall: 4.2” – April was even a couple inches below average for snowfall, but temperatures stayed cool enough to keep the winter season rolling along, and that’s what really helped make the period wintrier. We didn’t have any notable April snow accumulations down at our elevation, just a couple of small ones on the 2nd, and again on the 12th – 13th, but the mountains continued to get fresh snow right into mid month to keep surfaces in great form and the Mt. Mansfield snowpack robust.
Snowfall: 0.0” – There was no accumulating May snowfall down at the house this season, but that’s not too much of knock on the Month, because not getting snow in May is more the norm than actually getting snow. The mountains did get that beautiful Memorial Day weekend storm though, and the late season powder skiing was mighty fine. Although I can’t factor that directly into the analysis for the valley, it was quite cold in the valleys at the end of the month, and close to even snowing there.
There were a couple of other interesting notes with respect to snowfall this season:
1) Storm frequency and average storm size: Despite coming in below average for snowfall, the 2012-2013 season offered up a healthy 51 accumulating snowstorms, almost up there with the 53 storms we received in 2007-2008. Of course, to come in below average for snowfall with that many storms indicates that the average snowfall per storm was down, and indeed it was. At 2.8”/storm, 2012-2013 ranks down there with 2011-2012 (2.6”/storm), the only odd seasons out compared to the more typical seasons up near 4”/storm. For whatever reason, this season’s average came in on the low side. This is presumably due in part to many of the everyday events being on the small side, but also due to the lack of bigger storms, which is covered in point #2 below.
2) Storms with double-digit snowfall: It’s certainly an arbitrary and subtle distinction, but after looking through my data, I noticed an interesting trend with respect to each season’s largest storms for our location. In my season summaries, I always make a list of the top five storms of the season, and when the season seems to have gone well, all of those top five storms have been in the double digits for snowfall. In fact, the “best” seasons thus far have been able to surpass that five-storm threshold. For reference, here’s the top five list for this season, with the links to the detailed web pages for each storm:
Indeed, if we look at the number of storms with double-digit snowfall by the seasons, we see an obvious trend. With the number of double-digit snowfall storms listed in parentheses after the season, one notes those “good” seasons – 2007-2008 (6), 2008-2009 (7), 2010-2011 (7) seemed to find a way to exceed five double-digit storms, whereas the poorer snowfall seasons – 2006-2007 (4), 2009-2010 (2), 2011-2012 (3), 2012-2013 (4) just didn’t. Surely the law of averages comes into play here to some degree – seasons with patterns producing lots of snow likely have a greater chance of getting a big storm in here, but that’s not a given. It’s also very suspicious that those seasons that come in sort of in that middling ground like 2006-2007 and our season of interest for this summary, 2012-2013, fall just short of making the cut. I suspect this trend may be more intact in a location like ours because of the relatively high number of storms and snowfall, and upslope snow (which was on the low side this season) as an extra protection against huge snowfall variance, but this is going to be an interesting trend to follow into the future as a gauge of snowfall seasons.
In sum, while snowfall was certainly a bit below average, and snowpack was well below average, I’d still give the season a reasonable grade. If C is average, I’d go with a C- for 2012-2013, just a bit off from making the average. Were snowpack a more significant factor in my winter preferences, one could argue for going a bit lower, but at least minimal snowpack was maintained throughout the entirety of the winter to keep everything white. Overall it could have been a lot worse, and with the amount of snowfall we did get, it’s hard to drop the season into the D range, which, based solely on snowfall and snowpack at the house, is where I’d put a season like 2011-2012.
For a complete look at all the data, charts, graphs, and tables from the winter season, head to our Waterbury, VT 2012-2013 winter weather and snowfall summary page.