Speaking of Snow: Where are the Anomalies?

There has been lots of cringing in the northeastern U.S. and in eastern Canada this year about the amount of snow that has fallen. So, is the current snow cover — the amount of snow remaining on the ground — anomalous by historical standards?

Well, one way to answer that question is to to go to the Rutgers University Climate Lab, which maintains a nifty map that shows a graphical "diff" of current snow cover from satellite-based norms. And here is the answer as of yesterday, with purple areas denoting surplus snow. Looks like there is an area in the eastern U.S. with more snow on the ground than normal, but, that’s about it — other than a few areas in the Rockies (and lots in Europe) with less snow than usual.



  1. Hard to tell from the graph whether Toronto is in blue. Seems not to be.
    It should be.
    I am not convinced these people know what they are doing (I do not readily confuse the ahecdotal and the statistical).
    Or perhaps they have a goofy notion of normal.

  2. You’re confusing current snow cover with total show fall. Here in Montreal, we beat most records by mid-February, and we’re stilling getting hit hard – but every time it’s followed by a warm spell and everything melts.

  3. I’m not confusing snowfall with snow cover. I am just more interested in what stays behind than in what falls from the sky and immediately melts.

  4. I understand your distinction in Toronto really well. Normally on average we have no persistent snow cover, whatever variation we might have in total snowfall. What has been special this year is that we sure have persistence! I cannot tell from where the blue is on your graph whether these people know how to reflect that correctly.
    There is imply no question this winter is a total outlier in terms of total snow and its persistence here.
    If the data you are getting from these people does not show it (as I see it Windsor is included but not Toronto) you should not trust that data.

  5. All these charts are showing is whether a particular grid spot is mostly snow covered, and whether, historically, that is normal. There’s no gradation, and there are only four possible answers.
    Since most places in Canada are “normally” snow-covered throughout the winter, the only thing this chart would show in that season is when a significant part of Canada *doesn’t* have snow cover.
    Also, for the Toronto people — Toronto’s snow cover is anomalous from its surrounding area. Drive 50 km north, east or west from the lake shore, and you can bet there is a lot more snow normally on the ground. The grid on this chart is pretty coarse, so the dot that contains Toronto is showing a lot more than just the city.

  6. Also, more interesting IMO are the charts showing the average departure from the norm for a month:
    February 2008:
    January 2008:

  7. We just got another big snowfall here in Montreal.
    When people complain, it’s generally not about the total amount that’s on the ground; it’s about the amount they’ve had to shovel off their driveways and side-walks.
    So I guess your interests and those of the complainers aren’t really the same :)

  8. Gene Mate says:

    This bit of “data” seems rather useless. The only useful chart would be on total snow on the ground. And now that we here in Ottawa have had over 4 meters of the white stuff fall, when normal is about 2.5 meters, you know this is an anomalous winter regardless of what the good folks at Rutgers may compute.
    Of course, “normal” doesn’t exist as it’s just based on biased assumptions and recollections, coupled with computed averages. And I’ve yet to see a “normal” winter that hits all the “normal” temperatures or snowfalls.
    It’s winter, it’s white outside. Surprise.

  9. michael ferrari says:

    @gene mate- Climatlological Normal, as useless as the term may be scientifically, doesn’t have any ‘biases assumptions/recollections’ as you suggest. instead the values are simple calculated averages over a 30 year period. To say that the only chart that matters is total snow completely misses the point of constructing a map based on anomalies.

  10. Gene Mate says:

    @Michael Ferrari. I understand what you’re saying, but if they’re truly showing anomalies then the fact this is the 2nd worst winter in our history should show up on the map, and across a wide swath of the map no less.
    However, the map seems to simply show snow cover. And, well, snow cover is pretty normal in winter up here. This much snow isn’t. The average here is about 250cm and we have 410 on the ground. Still not a record — that’s 1970-71 with 444 — but still an anomaly.
    In the end, my use of “normal” in terms of biases was strictly based on the notion that people — and many scientists — proclaim certain weather to be “normal”. Thus, this winter isn’t “normal”, but that’s because people base what they’re going through on their recollection of seasons past.
    I’m always reminded of the weather descriptions at Valley Forge during the Revolutionary War. I look at those descriptions and then realize that that amount of snow hasn’t fallen in Valley Forge in decades, if not longer.

  11. michael ferrari says:

    @Gene Mate – per your reply, my point was that when using normal as a reference point, which most all climate papers do, the ‘normal’ does not include any subjectivity. discussions may use the term normal and may therefore be biased, but any map such as the one Paul posted is based solely on calculations and nothing more. Now there may be errors in the assumptions as to what defines a grid box, filling in missing data, etc, but there are no biases that are used to designate what normal is. What this also shows, which you refer to, is that ‘normal’ weather doesn’t have any real meaning other than for convenience.

  12. Gene Mate says:

    @Michael Ferrari. I’m in total agreement with you. It’s a general problem with the use of any language in trying to define something scientifically.
    And I do realize the map is based on calculations. All I’m saying is the selection of calculations don’t take into account the total gamut of anomalies. In Ottawa “normal” is snow in winter. However, anomalies include excessive snow, much less snow, or excessive ice. Last year we had very little snow (about 1 metre). This year we have excessive snow (4 metres and counting). In 1998 we had severe ice resulting in our Ice Storm. However, if you looked at ground cover and most “normal” measurements in 1998 the winter would have appeared “normal” when it was anything but normal.
    And that’s my problem with the map. It doesn’t truly describe anomalies as it purports to. 2008 is an anomalous year in Ottawa and the surround regions and yet it is not so listed on the map. The algorithms used to create the map are therefore too simplistic to capture our anomalies.