90th Anniversary of Knickerbocker Storm

[gymengineer]

Measurements on the mall more or less jived with DCA though they were a bit higher when I was down there midday. Not completely sure where it ended up as I left before it stopped.

 

May have an interesting lead on this issue though.. still investigating further. Hopefully can get more before this winter is over.

What issue? The 2/5-6/10 snowstorm in particular or DCA measurements?

[Scarlet Pimpernel]

No doubt they are as accurate as they can be given their situation IMO. There is nothing to prove otherwise. But, yeah.. everyone who pays attention knows DCA sucks at snow accumulation and is not what you'd expect in a large part of the city -- though I'd bet it's more representative even there than some think. Anyone saying the old location is for sure colder/snowier has probably not spent time within the main city boundaries during a snowstorm. On a lot of the other DCA complaints I think it's at least partly people not understanding that no location is fully representative of anything other than that location. I believe most temps (at least deep into seasons) etc are fairly representative of a decent part of downtown, or at least can be used as a baseline to make an educated guess based on local variations in topography etc.  On the flip side, it's hard to say an official station near American would be totally representative either. I moved about 1.5 miles halfway through 09-10, so I didn't get measurements at just one location.. I believe my final was about 70" though (have to see if I saved the stats anywhere).  Got 22" (I think on Feb 5-6)... not far from American.. I wonder if their numbers are a little inflated personally, but it is just about the highest part of the city so maybe not. 

 

I agree, thanks for the very good points here.  I think between what I said previously and what you mention here, the two biggest factors that emerge are proximity to the river and elevation differences within the District itself (this is probably very obvious, I know!).   I tend to take the DCA measurements with a bit of a grain of salt, and just figure it is what it is.  Snowfall measurements are so highly variable and fickle over even very small distances, compared to precipitation amounts or temperature.

 

The other thing to consider is the relative magnitude of measurements at DCA itself from big events, not necessarily to compare those to amounts where the "official" site was before it was at DCA.  For instance, as "crappy" as the 17.8" amount from Feb. 5-6, 2010 may seem (just looked up the exact number!), it did rank only 2nd behind the 1979 Presidents' Day storm at the DCA location.  That's also ahead of the PD-II storm and the Jan. 1996 blizzard, among others (note that Dec. 18-19, 2009 is in the top 10 as well).  So in a relative sense for that site, kind of impressive one could say.  I wonder what the Knickerbocker total would have been at the same exact DCA location. 

[Ian]

What issue? The 2/5-6/10 snowstorm in particular or DCA measurements?

 

DCA measurements. Not completely sure on it all but just recently got a lead on it. Have to investigate further.

[gymengineer]

When there are a lot of spotter reports, you can get a better sense of the overall range within a county or within DC, and you can also identify outliers (low or high) that don't make much sense based on location. Looking at all the reports, I think it's reasonable to say the 'low-lands' around DCA were in that 18-20" range-- but that 18-20" might be snow depth instead of snowfall (6-hr method) for some of the spotters, so might be on the low side. Those low elevation areas did start accumulating snow later than all the other places with elevation. On the CWG comments section that late afternoon into early evening, people near the water were starting the "bust" posts because they hadn't really started to accumulate yet.

[Ian]

BTW, Kevin has a book coming out in a week on this storm:

http://www.arcadiapublishing.com/9780738597904/The-Knickerbocker-Snowstorm

 

Should be interesting.. have seen some clips from it on CWG but nothing more.

[gymengineer]

I agree, thanks for the very good points here.  I think between what I said previously and what you mention here, the two biggest factors that emerge are proximity to the river and elevation differences within the District itself (this is probably very obvious, I know!).   I tend to take the DCA measurements with a bit of a grain of salt, and just figure it is what it is.  Snowfall measurements are so highly variable and fickle over even very small distances, compared to precipitation amounts or temperature.

 

The other thing to consider is the relative magnitude of measurements at DCA itself from big events, not necessarily to compare those to amounts where the "official" site was before it was at DCA.  For instance, as "crappy" as the 17.8" amount from Feb. 5-6, 2010 may seem (just looked up the exact number!), it did rank only 2nd behind the 1979 Presidents' Day storm at the DCA location.  That's also ahead of the PD-II storm and the Jan. 1996 blizzard, among others (note that Dec. 18-19, 2009 is in the top 10 as well).  So in a relative sense for that site, kind of impressive one could say.  I wonder what the Knickerbocker total would have been at the same exact DCA location. 

 

Yup, I posted the following in another thread last week (I do think that PDI *is* out-of-order, but the other rankings do shake out more or less representative for DC):

 

You can't compare DCA snow totals to pre-DCA storms (like 1899 or Knickerbocker), but the ranking of the major snowstorms since the move to DCA is more or less right for DC proper. The only exception is probably PDI-- Both 2/5-6/10 and 1/96 had higher snow totals across most of the city.

PDI- 18.7"

2/5-6/10- 17.8"

1/96- 17.1"

PDII- 16.7"

2/83- 16.6"

12/09- 16.4"

2/58- 14.4"

1/66- 13.8"

Some other recent storm totals that make sense within DCA's own rankings:

1/25/00- 9.3"

2/06- 8.8"

2/9-10/10- 10.8"         

 

 

As for the Knickerbocker storm, since temps were mostly in the 20's during the storm and mixing did not happen areawide, I would guess a repeat at DCA probably would have gone over 20" but fall short of 28".

[gymengineer]

DCA measurements. Not completely sure on it all but just recently got a lead on it. Have to investigate further.

I asked last winter and someone confirmed that the 'official' climate data was still unchanged--- any idea now if BWI's totals from before 09/10 will ever get revised?

There was definitely talk from the MIC at LWX about revisiting storms before the 09/10 season after the downward revisions of 2/5-6/10 and then 12/09 (lost 3 inches!). There was a general consensus then that for LWX to just use snow depth for snowfall total was not really better than the airport FAA contractor measuring too frequently.

If there are no more revisions, that would be a pretty glaring within-the-same-site inconsistency and the top-10 list for Baltimore will remain unusable for ranking purposes.