15 replies to this topic

[rgwp96]

  not to keep beating a dead horse but
The chart below was posted on eastern by Famartin  first number is total snowfall and second number is total snowdepth(what was actually on the ground once the snow stopped)  As you can clearly see the measuring techniques have certainly changed.  Sure the snow fluff factor was different but these differences are ridiculous.  No wonder there is so much skepticism with that record. 

1947
Central Park: 25.8/25
The Battery: 25.8/25
LaGuardia: 22.8/22
Newark: 26.0/22

2006:
Central Park: 26.9/17
Ave V Brooklyn: 16.4/16
LaGuardia: 25.4/16
Newark: 21.3/14

[satellite_eyes]

That is very interesting, thanks.  Well I know one thing.  It was a little tough to measure from what I remember but I definitely had a solid 11" on the ground when I measured. 

[robbbs]

Rgwp, good information; thanks for posting. I remember tallking to my architect about both storms -- he's 80 years old, has lived in Manhattan all his life, and remembers the '47 storm very well. He laughed when he heard that the 2006 storm was the "biggest snowstorm in Central Park history". He said it wasn't even close. The '47 storm stopped everything, as did several others. He took a walk in Central Park right after the 2006 snow ended and said it looked like any number of 1'+ snows, heavy but nothing out of the ordinary.

[weathergeek87]

RG, to answer your question from the other thread, 26" was total snowfall, but the snow of course began to compact once it stopped falling, but those differences are crazy bt both storms. I don't remember 96 too well but I think that storm reaked more havock on NYC than 06. Still, 06 was great IMO.

[weatherbowl]

2006 had that heavy band that did noit move, 1947 apparantly did not have anything like that. 1947 might have been worse but I really do not dispute the snow totals. There were numerous local reports to varify the Central Park report.

[rgwp96]

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2006 had that heavy band that did noit move, 1947 apparantly did not have anything like that. 1947 might have been worse but I really do not dispute the snow totals. There were numerous local reports to varify the Central Park report.

I think you are missing the point.  Seems the way they measure the snow has changed thus giving you alot more than what actually is on the ground.  Nobody had over 18 inches of actual snow on the ground yet they report it as 26+.  Look at the 1947 statistics, snowfall pretty much equalled snowdepth.  Now look at 2006 and snowfall didn't come close to what was on the ground.

[robbbs]

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2006 had that heavy band that did noit move, 1947 apparantly did not have anything like that. 1947 might have been worse but I really do not dispute the snow totals. There were numerous local reports to varify the Central Park report.

Weatherbowl, there's no disputing the Central Park 2006 snow total because that is the number "based on the new measurement guidelines". However, what many of us are saying is that 2006 still falls short of many previous snowstorms in NYC when the snows were measured differently. The change in measuring guidelines now makes historical comparisons difficult, if not impossible. Furthermore, it's confusing to nearly all people -- if there's a forecast for a foot of snow, most people would interpret that to mean that there will be a foot of snow or close to it on the ground at the storm's end. The 2006 storm, while measuring 27" of snow, at no point had anything like that on the ground. The new measuring guidelines have been ridiculed by many pro mets and NWS staff. Bad idea.

[weatherbowl]

I understand what your saying Robbbs and rgwp96,  it does make for difficult comparisons. However I think you can make an arguement for both types of measuring. Snow does compact, so if a storm is over and you measure 20 inches, 24 might have fallen. So which is better? I think for historical purposes, maybe we should keep the old method. However the new method may actually be better. Just a thought.

[weatherbowl]

When did the new way of measuring come to be. I seem to remember it being around for numerous years. One other thing, when we get these large snowfalls and I here of these huge amounts, I never seem to get them. I go measure and get 18 or so inches in most all the big storms we have had. I always feel left out.  LOL

[robbbs]

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When did the new way of measuring come to be. I seem to remember it being around for numerous years. One other thing, when we get these large snowfalls and I here of these huge amounts, I never seem to get them. I go measure and get 18 or so inches in most all the big storms we have had. I always feel left out.  LOL

Weatherbowl, the new snow measurement guidelines began in 1997. While the intent was to compensate for some of the compaction issues you mentioned earlier, the new guidelines only make things more complicated IMO and really skews the numbers for long duration events (since you can re-measure every 6 hours off a bare surface). There's no perfect solution but I go back to the basics -- when there's a  forecast for a foot of snow, that's what people expect to have on the ground if the forecast verifies.

[Stormchaser]

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I understand what your saying Robbbs and rgwp96,  it does make for difficult comparisons. However I think you can make an arguement for both types of measuring. Snow does compact, so if a storm is over and you measure 20 inches, 24 might have fallen. So which is better? I think for historical purposes, maybe we should keep the old method. However the new method may actually be better. Just a thought.

Weatherbowl - you're correct, although it's confusing when comparing past storms to present, the new methodology can be useful dependent on the situation. Below is a good example straight from the NWS guideline web page:

"For example, three separate snow squalls affect your station during your 24-hour reporting day, say 3.0, 2.2, and 1.5 inches. The snow from each event melts off before the next accumulation and no snow is on the ground at your scheduled time of observation. The total snowfall for that reporting 24-hour day is the sum of the three separate snow squalls, 6.7 inches, even though the snow depth on your board at observation time was zero. Snow often melts as it lands."

Those events in which 1) rain:snow ratios are extremely high, i.e, the snow rapidly compacts upon accumulating; or 2) storms with sfc temperatures marginal for accumulation, i.e., the snow begins to melt from the ground up. In these type of events, taking the total snow depth at the end of the storm would actual underestimate the amount of snow accumulated.

On the other hand, there are situations where the old methodology is more logical/useful - i.e, larger storms. As someone mentioned earlier, most folks prefer the total snow depth methodology as is more accurately represents the magnitude of the storm. The 6-hour clearance method, IMO, does tend to inflate snowfall amounts, particularly in significant to major storms. Personally I'd prefer a return to the older method - however - the new methodology can come in handy in particular situations (examples above).

[Stormchaser]

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Weatherbowl, the new snow measurement guidelines began in 1997. While the intent was to compensate for some of the compaction issues you mentioned earlier, the new guidelines only make things more complicated IMO and really skews the numbers for long duration events (since you can re-measure every 6 hours off a bare surface). There's no perfect solution but I go back to the basics -- when there's a  forecast for a foot of snow, that's what people expect to have on the ground if the forecast verifies.

We think alike. I just posted that the older methodology is more logical for the longer duration, more significant storms.

[satellite_eyes]

To me the only time you should "clear off" is if there is a break in the snowfall or if the snow turns to sleet/rain, etc.  Once the snow begins to fall again or the rain/sleet, etc. changes back to snow then it should be ok to start a "new" measurement even if it is the same storm.  The final total should be the total combined amount from each specific period.  To me that's the only time it makes the most sense.  However what stormchaser posted before from the NWS guidelines does make sense.  Maybe they can just start keeping 2 separate totals - actual amount on the grouind and total for the season.

[robbbs]

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We think alike. I just posted that the older methodology is more logical for the longer duration, more significant storms.

Storm, one more aspect of this that adds to even more confusion and/or inconsistency -- my understanding is that NOAA suggests the clearing off every 6 hours method but leaves it as an option for the local NWS office to utilize or not. Therefore, I'm sure some offices are using it while others do not. Another reason why snowfall comparisons between places will always have to be taken with some degree of question.

[Stormchaser]

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Storm, one more aspect of this that adds to even more confusion and/or inconsistency -- my understanding is that NOAA suggests the clearing off every 6 hours method but leaves it as an option for the local NWS office to utilize or not. Therefore, I'm sure some offices are using it while others do not. Another reason why snowfall comparisons between places will always have to be taken with some degree of question.

That's the problem - even on these weather boards - we don't know whether someone's using the 6-hr clearance method or the older methodology (possible reason for the large discrepancies over relatively short traveling distances). I guess we're going to have to announce what method we're using - along with the totals - during the winter season. My personal preference is the older method in most situations involving significant, 6"+, 6-hr+ type events.

[icehater]

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That's the problem - even on these weather boards - we don't know whether someone's using the 6-hr clearance method or the older methodology (possible reason for the large discrepancies over relatively short traveling distances). I guess we're going to have to announce what method we're using - along with the totals - during the winter season. My personal preference is the older method in most situations involving significant, 6"+, 6-hr+ type events.

What is interesting is the great snows that are reported in western NY as well. Although we all heard the great 120" snow fall reports in western NY there was really only about 65% of that amount on the ground when the snow took a breather. The bottom line is what are people's expectations. I'd bet that if you ask 100 people if Oswego got 120" of snow or NYC got 27" in 2006 how much snow they'd expect to see on the ground, 90+ would have expected the reported amounts to be on the ground not 2/3rd's of it.

On Christmas 2005 Caribou reporeted a record event 30" snowfall but when the last flake fell only 20" was on the ground. Clearly we need a better metric. In baseball pitch count for throws to first (or any) base don't count even though those throws are often harder than throws to the plate. It seems Mets, if they were BB scorekeepers, would differ with MLB and count those throws.