March 22-23 Storm Thread: Cabins and Pony-Os?

[Baroclinic Zone]

5 hours ago, Ginx snewx said:

You didn't grasp the science aspect,  its ok.

There is no scientific way to measure snow/snowfall without human interaction.  It's the only weather phenomenon that I know of that  has this. I feel getting across the impacts of any given potential snowfall is more important then what actually falls and/or is measured by any given observer.

[Baroclinic Zone]

16 minutes ago, OceanStWx said:

LCD sites measure differently because we've always had synoptic hour observations there. CoCoRaHS was created a decade ago. We don't ask volunteers to measure every 6 hours. 

Your measurement technique during the storm is fine. I don't decide what BOX keeps and what they don't. But I don't think you're understanding what I'm saying. I'm not saying wait to measure in 24 hour increments. You can measure as often as you like without clearing, but you can only report the highest snowfall amount in that observation window (whether it's 6 or 24 hours). 

If we really want to get into semantics about what snowfall really is, it's the amount of snow that fell from first flake to last. So really we should measure when the event ends. The only real reason people argue about measurement techniques is not because they want to be accurate, it's because they want to have higher totals.

Yep.  

[40/70 Benchmark]

3 minutes ago, Baroclinic Zone said:

Yep.  

Fine, stop paying people to measure and clear every 6 hours.

[backedgeapproaching]

1 hour ago, OceanStWx said:

CoCoRaHS and coops are reporting new snowfall. And a fluff bomb that compacts as it falls, to Brian's point, isn't that just part of what happens to snow. We're not measuring every flake as it stacks up, we're measuring what people have to deal with.

You guys asked what officially is new snowfall, and I gave the answer. It seems that some don't like the answer because it may take away a few inches at the end of the year. You're fine to clear the board every 6 hours, it won't be any different than a LCD site, but any more than that and you're not giving us a number comparable to the rest of our reports. 

CoCoRaHS seems to be Ok with either method.  You can do new snow at the end of the event or do 6 hour clears. I'm not sure how many are actually doing 6 hours vs "new snowfall"--I would think most are doing new snowfall and not clearing.  

Below is from their site:

One of the difficulties with accurate and consistent snowfall measurement is related to the melting, settling, or evaporation of snow before you have a chance to measure it (especially in the Fall and Spring). Please try to do a measurement as close in time to when the storm ends as possible. Don't wait until 7AM if the snow ended the previous day. During long-duration snowfalls, you may choose to measure and clear the snowboard every six hours. The total snowfall would then be the summation of the different measurements.

 

[tamarack]

2 hours ago, OceanStWx said:

I honestly think you are exaggerating how much totals are inflated by measuring the greatest depth of new snow and measuring and clearing every 6 hours. If you went out every hour and measured new snow, reporting the greatest number you saw, but didn't clear the board until 24 hours your total is not going to be that far off 6 hour clearings. If rates are extreme and you stick a ruler in frequently enough, you'll capture a higher total before compaction. In fact that number may be higher than if you waited until the end of the 6 hour period to measure. 

Depth and new snow are fundamentally different. One is the amount on the ground, the other is what has accumulated on your snow board over the event. I'm not saying that we're looking for a report of the change in snow depth. We're looking for the greatest amount of new snow on your board over the course of the event. 

Exaggerating, maybe, but I think it can be significant.  Becoming a wx weenie in my NNJ days, the NYC records were the gold standard (thank you Unc Wethbee) and the late Dec. dump in 1947 the unchallenged champion.  Now it sits at #3.  However, it added more depth than either of the current top 2, though 2016 is close (and the 26.9" of 2006 never registered more that 16" depth, which really makes me wonder.)

Another variable in the 24-hr-or-greatet-depth method comes when the obs time is at/near the height of the storm.  If there's 10" and puking snow at cocorahs' 7 AM time, I'll take a core and clear the board, such that the 8" max when accumulation stops at 2 PM means an 18" event, even if there's only 16" in my unplowed driveway due to compaction.  If that same storm had come 8 hours earlier, it would have measured 16" at 7 AM.  C'est la vie, I suppose.

[Baroclinic Zone]

23 minutes ago, 40/70 Benchmark said:

Fine, stop paying people to measure and clear every 6 hours.

Why?  Is what they are reporting inaccurate based on current accepted methodology?  You know what you measured was accurate.  You only took issue when what you reported was taken off the PNS.  Does it diminish in any way what fell in your location vs the ones left on the list? 

[dendrite]

BUF had 81.5” in a 5 day span during Dec 2001, yet their highest depth was “only” 44”. They may have had 120” if they cleared every 3 hours.

[40/70 Benchmark]

15 minutes ago, Baroclinic Zone said:

Why?  Is what they are reporting inaccurate based on current accepted methodology?  You know what you measured was accurate.  You only took issue when what you reported was taken off the PNS.  Does it diminish in any way what fell in your location vs the ones left on the list? 

It compromises the integrity of the data when measuring methodologies are not homegeneous.

[40/70 Benchmark]

14 minutes ago, dendrite said:

BUF had 81.5” in a 5 day span during Dec 2001, yet their highest depth was “only” 44”. They may have had 120” if they cleared every 3 hours.

Perfect example. Corahs would report 44" snowfall....yet the 6 hour swipe produced a total of 81.5".

[dendrite]

Just now, 40/70 Benchmark said:

Perfect example. Corahs would report 44" snowfall....yet the 6 hour swipe produced a total of 81.5".

Well that is depth over 5 days so you would at least get a handful of clearings in. But yeah...maybe 55-60” instead of 44”?

They also went from a depth of 44” to 29” in a few days despite the warmest temp in that period being 25°. 

[BombsAway1288]

1 hour ago, 40/70 Benchmark said:

That may be about as extreme and localized event that you will see in sne, but ME gets those fairly frequently due to norluns.

Yeah I forgot about Maine. They are the most favored in terms of history to score on norluns. I think Connecticut gets their share also for whatever reason. I remember for years (like the last 20), whenever the models would show a norlun setup in NNJ but we all knew that ultimately that would shift NE into CT, which it would usually do for whatever reason.

[Baroclinic Zone]

10 minutes ago, 40/70 Benchmark said:

It compromises the integrity of the data when measuring methodologies are not homegeneous.

The only compromising is if you are trying to compare one site vs another if they use different accepted measuring methods.  The integrity of the data for the individual site is correct/accurate.  Because snow is inherently a difficult thing to measure, I have no issue with different methods being accepted.

[40/70 Benchmark]

1 minute ago, Baroclinic Zone said:

The only compromising is if you are trying to compare one site vs another if they use different accepted measuring methods.  The integrity of the data for the individual site is correct/accurate.  Because snow is inherently a difficult thing to measure, I have no issue with different methods being accepted.

Exactly...I'm not sure why you would't want to compare sites.

[Baroclinic Zone]

26 minutes ago, 40/70 Benchmark said:

Exactly...I'm not sure why you would't want to compare sites.

I'm not saying to not compare sites, but the differences in totals would likely be minimal over any given season/storm, and it really doesn't make a huge difference in real-world impact from a day to day perspective.  I would think that is more important to the NWS.

[Ginx snewx]

1 hour ago, Baroclinic Zone said:

There is no scientific way to measure snow/snowfall without human interaction.  It's the only weather phenomenon that I know of that  has this. I feel getting across the impacts of any given potential snowfall is more important then what actually falls and/or is measured by any given observer.

I vote bullshit if you value data

[dendrite]

idk if they’re as concerned about comparing different sites as much as they are keeping the same measuring methods for sites over the historical data period. The COOPs have been measuring only at 6-8am for a long time because they’re just volunteers that have other jobs and responsibilities too. The LCDs have historically had paid observers measuring hourly at the airports for many decades now. So they are keeping the 6hr measuring there to keep the methodology continuous. 

I’ve always thought 6-8 hours was a happy middle ground for allowing some compaction, but not letting it sit too long. I’ve always mimicked CON with my observing methods so I’ve stuck to 6hrs when I can. But part of me wishes I started at 8hrs so I could measure, go to bed, sleep 7.5hrs, and then wake up to an on-time measurement rather than setting my alarm for 11z after measuring at 5z. lol

[Baroclinic Zone]

4 minutes ago, Ginx snewx said:

I vote bullshit if you value data

That's your opinion.  My opinion would be to move to measuring what has fallen at the end of any given specific snowfall and report that.

[powderfreak]

4 hours ago, OceanStWx said:

I honestly think you are exaggerating how much totals are inflated by measuring the greatest depth of new snow and measuring and clearing every 6 hours. 

It definitely can make a large difference up this way.  Probably the same in lake effect.

I mean JSpin probably has events that totaled 18" but max snow depth is 12-13".  I'll look for examples later but early season events you can see it as the new snow in a protracted 24 hour event is vastly different than the snow depth.  

I feel like we've had that discussion on here before when a November event with bare ground has someone asking JSpin how he got 14" but the snow depth is 9". 

If you get 3.5" every 6 hours for 24 hours or even 36 hours like can happen, that stuff settles on itself quite a bit over time despite constant snowfall.  In a climo where it can literally snow for days at a time, even if just 1.7" in 6 hours but then 5.1" in the next interval, then 0.6", etc.... the 6-hourly method is the best by far not a max depth in 24 hours.

[dendrite]

3 minutes ago, Baroclinic Zone said:

That's your opinion.  My opinion would be to move to measuring what has fallen at the end of any given specific snowfall and report that.

See I just hate that. You penalize the snow in the second half of a major storm because of all of the weight building upon the first half. In those LES events, at some point the depth almost stops growing because for every 3” you had you probably compact 2”.

[dendrite]

Just now, powderfreak said:

It definitely can make a large difference up this way.  Probably the same in lake effect.

I mean JSpin probably has events that totaled 18" but max snow depth is 12-13".  I'll look for examples later but early season events you can see it as the new snow in a protracted 24 hour event is vastly different than the snow depth.  

I feel like we've had that discussion on here before when a November event with bare ground has someone asking JSpin how he got 14" but the snow depth is 9". 

He measures on an elevated board too. Those early season fluff events struggle on the depth side of things since there’s still enough warmth in the ground to try to slowly melt/compact it from the bottom upward. When it’s 31° in Novie and pounding upslope fatties it gives the measuring surface a cooler surface to accumulate on.

[#NoPoles]

Well, seems like the only solution is for interested parties to do an experiment. Set up multiple snowboards, use the different measuring techniques, and then you will know for sure how the different measuring techniques effect storm total. Unfortunately, winter is waning. This would be interesting to follow for next season if we had a few posters willing to participate and share the data

[dendrite]

Just now, #NoPoles said:

Well, seems like the only solution is for interested parties to do an experiment. Set up multiple snowboards, use the different measuring techniques, and then you will know for sure how the different measuring techniques effect storm total. Unfortunately, winter is waning. This would be interesting to follow for next season if we had a few posters willing to participate and share the data

It’s been done many times. I’ll look for some of them later, but I need to go out and corral some chooks.

[dendrite]

5 minutes ago, powderfreak said:

It definitely can make a large difference up this way.  Probably the same in lake effect.

I mean JSpin probably has events that totaled 18" but max snow depth is 12-13".  I'll look for examples later but early season events you can see it as the new snow in a protracted 24 hour event is vastly different than the snow depth.  

I feel like we've had that discussion on here before when a November event with bare ground has someone asking JSpin how he got 14" but the snow depth is 9". 

If you get 3.5" every 6 hours for 24 hours or even 36 hours like can happen, that stuff settles on itself quite a bit over time despite constant snowfall.  In a climo where it can literally snow for days at a time, even if just 1.7" in 6 hours but then 5.1" in the next interval, then 0.6", etc.... the 6-hourly method is the best by far not a max depth in 24 hours.

You guys need some of these at the ski area. I think they’re replacing the snow pillows in many sites.

https://www.sommer.at/en/products/snow-ice/snow-scales-ssg-2

[powderfreak]

2 minutes ago, dendrite said:

He measures on an elevated board too. Those early season fluff events struggle on the depth side of things since there’s still enough warmth in the ground to try to slowly melt/compact it from the bottom upward. When it’s 31° in Novie and pounding upslope fatties it gives the measuring surface a cooler surface to accumulate on.

Ahh fair enough and good point.  He's lucky to never have any wind.  

I do think 6-hourly is the best method in this climate zone when you can have light accums for days on end.  Always brushing those car toppings off every time you need to drive somewhere.  

[powderfreak]

Just now, dendrite said:

You guys need some of these at the ski area. I think they’re replacing the snow pillows in many sites.

https://www.sommer.at/en/products/snow-ice/snow-scales-ssg-2

That looks awesome.  I would love to have accurate SWE for snowfall rather than just biweekly surveys.  

I love seeing the differences as sometimes you get an upslope event with great growth and 9" out of 0.28" water...then you'll get a -4C 850 event where 1.08" water brings 9" of needles and graupel.  

[powderfreak]

A lot of weather data runs in 6-hour increments too... models run every 6 hours, the ASOS tallies up precip every 6 hours, it just seems like that's a good interval for weather observing too.  

[Baroclinic Zone]

30 minutes ago, dendrite said:

See I just hate that. You penalize the snow in the second half of a major storm because of all of the weight building upon the first half. In those LES events, at some point the depth almost stops growing because for every 3” you had you probably compact 2”.

But it takes any human element out of the measurement.

[40/70 Benchmark]

24 minutes ago, tamarack said:

Exaggerating, maybe, but I think it can be significant.  Becoming a wx weenie in my NNJ days, the NYC records were the gold standard (thank you Unc Wethbee) and the late Dec. dump in 1947 the unchallenged champion.  Now it sits at #3.  However, it added more depth than either of the current top 2, though 2016 is close (and the 26.9" of 2006 never registered more that 16" depth, which really makes me wonder.)

Another variable in the 24-hr-or-greatet-depth method comes when the obs time is at/near the height of the storm.  If there's 10" and puking snow at cocorahs' 7 AM time, I'll take a core and clear the board, such that the 8" max when accumulation stops at 2 PM means an 18" event, even if there's only 16" in my unplowed driveway due to compaction.  If that same storm had come 8 hours earlier, it would have measured 16" at 7 AM.  C'est la vie, I suppose.

9/10 time he is right...its NBD...but the one time out of ten that it is a big deal is the one of the most climo significance.

[OSUmetstud]

2 hours ago, dendrite said:

Well that is depth over 5 days so you would at least get a handful of clearings in. But yeah...maybe 55-60” instead of 44”?

They also went from a depth of 44” to 29” in a few days despite the warmest temp in that period being 25°. 

Thats a 5 day les storm. Lots of compaction. Look at the elma report from nov 2014. That was 57" depth after about 90-100" in 60 hours. 

[40/70 Benchmark]

1 hour ago, powderfreak said:

It definitely can make a large difference up this way.  Probably the same in lake effect.

I mean JSpin probably has events that totaled 18" but max snow depth is 12-13".  I'll look for examples later but early season events you can see it as the new snow in a protracted 24 hour event is vastly different than the snow depth.  

I feel like we've had that discussion on here before when a November event with bare ground has someone asking JSpin how he got 14" but the snow depth is 9". 

If you get 3.5" every 6 hours for 24 hours or even 36 hours like can happen, that stuff settles on itself quite a bit over time despite constant snowfall.  In a climo where it can literally snow for days at a time, even if just 1.7" in 6 hours but then 5.1" in the next interval, then 0.6", etc.... the 6-hourly method is the best by far not a max depth in 24 hours.

That blizzard for me last season, at its height, was akin to a late effect band...exquisite snow growth and just pouring fluff. What compounded the discrepancy is that I cleared just at the most intense part began, so it couldn't compact.