Question regarding Snowfall Averages

[CT Rain]

yup take a look at jspin's number for waterbury at 500'. he is the most dedicated meticulously poster and he is sorta "rewarded in a fair sense with higher totals" especially when measuring 50% or more upslope fluff.

most measure less meticulously and while still being by the book...skew the totals...i'd say if jspin measured every 24 hours his totals wold be reduced by a 15-20% compaction. let me STRESS j.spin measures by the book and his totals are accurate but not every station has the time OR committment to measure like that so there numbers will be down. Not saying this is the case in norfolk (for those years) but if there is evidence that period was a bit snowier AND someone was measuring every 6 hours i think we may be suprised "disturbed" to see how much things could change

Absolutely correct. He's doing things correctly and meticulously. I wish everyone could measure like that but I understand that most people don't have the time.

If Norfolk's average is in reality 80" measuring once a day at 12z... then I could see how (especially during a relatively snowy period) you could start racking up 25-30 year averages over 100 inches if you measured meticulously multiple times per day. All conjecture... I am not sure what actually was taking place up there.

[powderfreak]

yup take a look at jspin's number for waterbury at 500'. he is the most dedicated meticulously poster and he is sorta "rewarded in a fair sense with higher totals" especially when measuring 50% or more upslope fluff.

most measure less meticulously and while still being by the book...skew the totals...i'd say if jspin measured every 24 hours his totals wold be reduced by a 15-20% compaction. let me STRESS j.spin measures by the book and his totals are accurate but not every station has the time OR committment to measure like that so there numbers will be down. Not saying this is the case in norfolk (for those years) but if there is evidence that period was a bit snowier AND someone was measuring every 6 hours i think we may be suprised "disturbed" to see how much things could change

Yes... you have to know the measuring technique. J.Spin is a man of science and he is also extremely dedicated to getting as many 6-hour measurements as possible throughout the course of a winter. And in a place where snow is in the air almost perpetually, all those 6-hour 0.5" dustings add up in between the big storms. Upslope fluff, if measured at the right time, will give you huge seasonal totals (ie, J.Spin and other CoCoRAHS snowfall averages of 150-200" in populated areas). Two winters ago, Underhill Village at 1,000ft or lower had like 220" of snowfall per CoCoRAHS. Most folks would say that there's no way a relatively low elevation spot could get that much snowfall. Same with J.Spin in Waterbury at 500ft getting 150-200" fairly regularly. Even here in Stowe the CoCoRAHS observer in the "lower Village" one of the lower snowfall areas in town had 150" while up the Mountain Road snowfall ranged up to 240" by the time the road hit the ski resort.

These are huge snowfall totals for populated areas with bars, restaurants, shops, etc... but you don't get 150-200" of snowfall in this area of the northeast by waiting for the snowfall to settle. If you measured 24 hours after snow stopped, I bet those seasonal snowfall totals would be only 2/3rds of those numbers.

Also, 240" in Maine from synoptic snow would be a completely different ball game from 240" here... maybe its the same in Litchfield with dying lake effect and upslope. 115" in Norfolk, CT might be different than if Kev in Tolland got 115".

I wish I could do pure 6-hourly measurements at the ski resort but alas, I'm pretty much able to only get 2 per day during storms (early morning, and afternoon end of day).

[N. OF PIKE]

powder freak speaking of which ur snowfall totals should have an...* next to them as well.

but in a good way . this winter goes down in the record for you as 210" however u omit a pretty damn snow april and i iwould argue your total is skewed because the amount of days ur measuring snow fall for is skewed due to financial decisions made by stowe mtn owners.

your probably up to 250 or so at the 3K+ snowboard and you've had a memorable april earning your turns but the total is somewhat handicapped by managements decison to close because it's not like the 250" fell in a month when ur usually not running the lifts.

so in essense you 320 or so average is probably 350 or more annually when taking into account the snow that falls in the calendar year (not the ski operaton season) just wow!

[powderfreak]

powder freak speaking of which ur snowfall totals should have an...* next to them as well.

but in a good way . this winter goes down in the record for you as 210" however u omit a pretty damn snow april and i iwould argue your total is skewed because the amount of days ur measuring snow fall for is skewed due to financial decisions made by stowe mtn owners.

your probably up to 250 or so at the 3K+ snowboard and you've had a memorable april earning your turns but the total is somewhat handicapped by managements decison to close because it's not like the 250" fell in a month when ur usually not running the lifts.

so in essense you 320 or so average is probably 350 or more annually when taking into account the snow that falls in the calendar year (not the ski operaton season) just wow!

That's true... I always forget that even myself. October snowfall never makes it into our numbers and there have been some big whoppers in the last 10 years in October. This season on our snowfall report (financial weeks and snowfall get combined) we have a big goose egg 0" for April... when in reality its around 36-40".

[tamarack]

These are huge snowfall totals for populated areas with bars, restaurants, shops, etc... but you don't get 150-200" of snowfall in this area of the northeast by waiting for the snowfall to settle. If you measured 24 hours after snow stopped, I bet those seasonal snowfall totals would be only 2/3rds of those numbers.

Also, 240" in Maine from synoptic snow would be a completely different ball game from 240" here... maybe its the same in Litchfield with dying lake effect and upslope. 115" in Norfolk, CT might be different than if Kev in Tolland got 115".

All true, including the parts of your post I chopped for space-saving. 25:1 upslope is lots different from 10:1 synoptic, which is mostly what I've measured in Maine. Some ratios from 4 Maine locations, only for events 4"+ as I've not tabulated many of the smaller ones:

Bangor (3 yr)....9.8 to 1

Ft.Kent (10 yr)...11.6 to 1

Gardiner (13 yr)...10.0 to 1

N.Sharon (14 yr)...10.6 to 1

Some ratio climb as one gets inland/north, but all are far different from upslope/LES.

One can also look at snow depths. Using Farmington (as usual), with good snowpack measurements beginning 1/1/1941, thus 71 yr records (there are a very few depth numbers back to near 1900, but only 16 individual dates in 40 yr, thus worthless.)

In 71 years:

52% (37) have reached 30"

37% (26) made 35"

25% (18) made 40"

Only 10% (7) have gotten to 45" and just 4 years reached 50".

J.Spin's snowfall runs about twice mine or more, but IIRC, his snowpack numbers and mine are fairly close, as would be expected when comparing 20:1 stuff to 10:1, and his conscientious measurements to my twice-a-days (at best.)

[powderfreak]

All true, including the parts of your post I chopped for space-saving. 25:1 upslope is lots different from 10:1 synoptic, which is mostly what I've measured in Maine. Some ratios from 4 Maine locations, only for events 4"+ as I've not tabulated many of the smaller ones:

Bangor (3 yr)....9.8 to 1

Ft.Kent (10 yr)...11.6 to 1

Gardiner (13 yr)...10.0 to 1

N.Sharon (14 yr)...10.6 to 1

Some ratio climb as one gets inland/north, but all are far different from upslope/LES.

One can also look at snow depths. Using Farmington (as usual), with good snowpack measurements beginning 1/1/1941, thus 71 yr records (there are a very few depth numbers back to near 1900, but only 16 individual dates in 40 yr, thus worthless.)

In 71 years:

52% (37) have reached 30"

37% (26) made 35"

25% (18) made 40"

Only 10% (7) have gotten to 45" and just 4 years reached 50".

J.Spin's snowfall runs about twice mine or more, but IIRC, his snowpack numbers and mine are fairly close, as would be expected when comparing 20:1 stuff to 10:1, and his conscientious measurements to my twice-a-days (at best.)

Great data... I was hoping you would chime in on this. I always think of folks like you and Allenson when we discuss this stuff because often you guys have the same exact amount of snow on the ground as us in the upslope region, but did it with half the "snowfall." And then in the spring, you guys have better snow retention being further east, so you'll often have snow on the ground longer anyway.

I need to start calculating and recording snow depth days, as I think that value is a much better indicator of how good a winter is. If you plot your snow depths, the snow depth days value is the area under the curve and that will always show the true story of a winter. We could get 300" of snowfall but if there's never more than 24" on the ground due to lots of warmth and thaws, is it really as great as a winter where you get 160" but have snow depths of 4-5 feet for 2 months?

I love snowfall but I also have a snowpack fetish so I'm always up for more synoptic storms over upslope... but in a winter like last winter, upslope definitely helps when there's no synoptic storms. However, we're still going to come in with a below normal winter because upslope won't compensate for a dearth of synoptic storms.

[dendrite]

I believe someone in the BUF area has done some research comparing different measuring intervals in LES events. Come to think of it, it may have been Lake Effect King on here. I think I recall a more formal paper on it too.

[CapturedNature]

I agree with you when you look at the body of records those weenie years truly do jump out at you.

It certainly could be an issue or specifically where/how snow was measured in those years. I think we all get a little too cute and precise when it comes down to nailing specific seasonal averages. If you start measuring every 6 hours as compared to every 24 (not necessarily when a storm ends but at 12z) you can get some fairly substantial differences. I'm not saying one is right over another but I could see the difference between measuring at 12z only and measuring through the duration of a storm and immediately following snowfall can inflate the totals somewhat dramatically.

This is the problem that I have with the new standard of measuring every 6 hours instead of at the end of the storm. You run into statistical issues compare storms of today with storms 50 years ago. I started in the mid-80s measuring at the end of snowfall and stuck with doing that so I could compare snowfall. I agree that measuring ever 6 hours can inflate snow totals

I'm a little confused by the comment of measuring every 24 hours and only at 12z. Who measures like that? I was a co-op and even took a class on being an observer while I was at LSC. The 12z ob is when you record temperature max/min, liquid precip for the previous 24 hours and snow on ground (SND). Snowfall for the previous 24 hours is measured at the end of a snowfall. If you have one 3 hour period of snow and you get 3" of snow, you record 3.0". If you have three of those you'd record 9.0". I'm not aware of anyone who waits till 12z to measure how much snow fell. That's just being a poor observer.

That being said, I do think that anything close to 100" is too high for Norfolk. 75" to maybe 85" at the high end is what I would guess.

[CT Rain]

This is the problem that I have with the new standard of measuring every 6 hours instead of at the end of the storm. You run into statistical issues compare storms of today with storms 50 years ago. I started in the mid-80s measuring at the end of snowfall and stuck with doing that so I could compare snowfall. I agree that measuring ever 6 hours can inflate snow totals

I'm a little confused by the comment of measuring every 24 hours and only at 12z. Who measures like that? I was a co-op and even took a class on being an observer while I was at LSC. The 12z ob is when you record temperature max/min, liquid precip for the previous 24 hours and snow on ground (SND). Snowfall for the previous 24 hours is measured at the end of a snowfall. If you have one 3 hour period of snow and you get 3" of snow, you record 3.0". If you have three of those you'd record 9.0". I'm not aware of anyone who waits till 12z to measure how much snow fell. That's just being a poor observer.

That being said, I do think that anything close to 100" is too high for Norfolk. 75" to maybe 85" at the high end is what I would guess.

Depends on whether you actually have someone at that location to measure when the snow stops falling. Are all coops manned 24 hours? Ideally you'd measure when snow stops falling but I'm not sure that's done everywhere. I could be wrong, however.

Agreed on the 6 hour. It's fine if that's the standard everywhere but even with weenies on the board who are up every second of every flake they don't even measure like that (some just slantstick at the end and get the same result, though) so it's challenging to compare measurements for the same storm nevermind a storm 50 years ago.