October 29/30 Snowstorm OBS thread

[weatherwiz]

Below 450K now w/o power in CT for CL&P customers. 449,246 (36%) as of 3:14 AM.

[CT Rain]

Re the BDL total.... I think it's high but given the amount of compaction and the fact we were 34 most of the storm I'm not sure how much inflation 3 snow board clears could give you. We have a reliable depth measurement of 15" from e granby (maybe 1 or 2 miles from BDL) from Sunday morning. Seems to me if you cleared every 6 hours )and was measuring on a board not a warm ground) that you could tack on a few inches??? Thoughts ?

[Ginx snewx]

Re the BDL total.... I think it's high but given the amount of compaction and the fact we were 34 most of the storm I'm not sure how much inflation 3 snow board clears could give you. We have a reliable depth measurement of 15" from e granby (maybe 1 or 2 miles from BDL) from Sunday morning. Seems to me if you cleared every 6 hours )and was measuring on a board not a warm ground) that you could tack on a few inches??? Thoughts ?

Great blog yesterday, even heard on national CBS radio this morning about the uproar from Mets. That would be a helluva compaction, what was the w/e?

[CoastalWx]

Re the BDL total.... I think it's high but given the amount of compaction and the fact we were 34 most of the storm I'm not sure how much inflation 3 snow board clears could give you. We have a reliable depth measurement of 15" from e granby (maybe 1 or 2 miles from BDL) from Sunday morning. Seems to me if you cleared every 6 hours )and was measuring on a board not a warm ground) that you could tack on a few inches??? Thoughts ?

I still think it seems pretty high I suppose I could see 15-17", but 20.3? If they were like 700' I could buy it. I don't see many totals like that in Litchfield county. I'll have to go back and look at the radar.

[weatherwiz]

20.3'' does seem a bit of a stretch...like Scott said perhaps something around 15'' would be possible. Not sure why the changed occurred though from 12.3'' all the way up to 20''...where did this all come from?

Highest total in Hartford CTY from the PNS is 17'' in Bristol, CT.

Litchfield's highest toals are; Bakersville with 18.6''; Winstead with 18'' and Litchfield with 16.5''.

I assume the 11.5'' on the PNS from West Hartford is from Ryan? I would find it hard to believe BDL got 10'' more than here judging by what I saw on radar...doesn't appear they were in a band any longer than West Hartford was.

[snowman21]

20.3'' does seem a bit of a stretch...like Scott said perhaps something around 15'' would be possible. Not sure why the changed occurred though from 12.3'' all the way up to 20''...where did this all come from?

Highest total in Hartford CTY from the PNS is 17'' in Bristol, CT.

Litchfield's highest toals are; Bakersville with 18.6''; Winstead with 18'' and Litchfield with 16.5''.

I assume the 11.5'' on the PNS from West Hartford is from Ryan? I would find it hard to believe BDL got 10'' more than here judging by what I saw on radar...doesn't appear they were in a band any longer than West Hartford was.

Wonder how many of the measurements on the PNS were clearing their snow board (if they were even using one) every six hours? I suspect most people just stick the ruler in the ground and that's the measurement. That being the case means we're comparing apples to oranges assuming the observer at BDL was following proper snowfall measuring procedure (though I have my doubts about that given past performance). Along the shoreline I bet there was underestimation as the snow fell, then melted, then fell again, and people measured at the end reporting that number as the total instead of the sum of the maximum depth within six hourly periods. Compaction rates double for temperatures above 32, so it becomes harder and harder to accumulate snow no matter how hard it snows thanks to overburdening. There are plenty of temperature-based snow compaction and metamorphosis models out there for those willing to crunch numbers - Alta-LaChapelle, Pomeroy, Diamond-Lowry, and Fassnacht, to name a few. There was a confex paper floating around (I've seen it on the AMS site) co-authored by the Weather Channel of all places about creating high resolution gridded snowfall using a model based on temperature and water equivalent. So there are a number of ways to at least compute ballpark figures, but obviously nothing beats proper measurement technique. Without knowing how all the measurements were taken it's hard to dispute even with PNS in-hand, and the longer we go the better the chance of that 20.3 number sticking as it'll be up to NCDC to correct (which they won't).

[CT Rain]

Wonder how many of the measurements on the PNS were clearing their snow board (if they were even using one) every six hours? I suspect most people just stick the ruler in the ground and that's the measurement. That being the case means we're comparing apples to oranges assuming the observer at BDL was following proper snowfall measuring procedure (though I have my doubts about that given past performance). Along the shoreline I bet there was underestimation as the snow fell, then melted, then fell again, and people measured at the end reporting that number as the total instead of the sum of the maximum depth within six hourly periods. Compaction rates double for temperatures above 32, so it becomes harder and harder to accumulate snow no matter how hard it snows thanks to overburdening. There are plenty of temperature-based snow compaction and metamorphosis models out there for those willing to crunch numbers - Alta-LaChapelle, Pomeroy, Diamond-Lowry, and Fassnacht, to name a few. There was a confex paper floating around (I've seen it on the AMS site) co-authored by the Weather Channel of all places about creating high resolution gridded snowfall using a model based on temperature and water equivalent. So there are a number of ways to at least compute ballpark figures, but obviously nothing beats proper measurement technique. Without knowing how all the measurements were taken it's hard to dispute even with PNS in-hand, and the longer we go the better the chance of that 20.3 number sticking as it'll be up to NCDC to correct (which they won't).

Yeah I do agree that most of the totals we have are just snow depths from after the storm.

That said we received very few snowfall measurements in northern and western CT (normally we get about 100 for a storm like this) because no one had power.

I agree that the 20.3" sounds high... but I wouldn't be surprised if proper 6-hour snowboard clearing resulted in unusually high totals for this event given how exceptionally warm it was at the surface. Not to mention the fact I noticed there was a tremendous amount of melting 'from below' with the warm and unfrozen ground effectively melting the bottom inch of accumulation even on the grass. Is it possible to go from a 14 or 15" depth to a 20" total by clearing a snowboard? That's what I don't know.

[CT Rain]

Great blog yesterday, even heard on national CBS radio this morning about the uproar from Mets. That would be a helluva compaction, what was the w/e?

w.e. didn't report initially. Haven't looked back yet.

[CT Rain]

FWIW I had a 18" total depth Sunday AM from one of our mets in granby... at like 800 ft.

[Ginx snewx]

FWIW I had a 18" total depth Sunday AM from one of our mets in granby... at like 800 ft.

The highest w/e I see on Coco Rahs is 1.84 from Brookfield NGRANBY had 1.42 with 16.2 new

[Damage In Tolland]

FWIW I had a 18" total depth Sunday AM from one of our mets in granby... at like 800 ft.

LOL The boss def slant sticks

[Damage In Tolland]

My final total was 12.5 but that was measured about 7:00am if I recall

[Organizing Low]

This just in....CLP planning to cut power to Ryan Hanrahan's house.

[ChrisM]

Yeah I do agree that most of the totals we have are just snow depths from after the storm.

That said we received very few snowfall measurements in northern and western CT (normally we get about 100 for a storm like this) because no one had power.

I agree that the 20.3" sounds high... but I wouldn't be surprised if proper 6-hour snowboard clearing resulted in unusually high totals for this event given how exceptionally warm it was at the surface. Not to mention the fact I noticed there was a tremendous amount of melting 'from below' with the warm and unfrozen ground effectively melting the bottom inch of accumulation even on the grass. Is it possible to go from a 14 or 15" depth to a 20" total by clearing a snowboard? That's what I don't know.

I didn't measure properly with clearing but I measured 18" at 930 am. I'm thinking I may have gotten near two feet. With the temperature and snow weight I really think the snow could have compacted 5 or 6 inches by then...goi.g with 20" though toward my season running total

[CoastalWx]

If you look at BDL, although they were deep into the good echoes, the heaviest snow still seemed to be just nw of them for a time as well.

[ORH_wxman]

i don't think there is a chance BDL came within 4" of 20"...that total sticks out like a sore thumb. Compaction with this type of heavy wet snow is going to be a lot less than Feb 06 fluffy dendrites.

[ChrisM]

i don't think there is a chance BDL came within 4" of 20"...that total sticks out like a sore thumb. Compaction with this type of heavy wet snow is going to be a lot less than Feb 06 fluffy dendrites.

I don't see them being within 6 inches even of my total. My guess is they got about 14"

[Damage In Tolland]

BDL did not have 20 inches. I'm in Windsor and there is 0 evidence snowbankwise or otherwise they had that. There are a few peeps that are actually here today even with no power in the place that live in Windsor..and they all say they had around a foot

[ChrisM]

BDL did not have 20 inches. I'm in Windsor and there is 0 evidence snowbankwise or otherwise they had that. There are a few peeps that are actually here today even with no power in the place that live in Windsor..and they all say they had around a foot

To compare, where I live got somewhere between 18-22 and there is.still snow in all but the sunniest spots

[Cold Miser]

. . . but I wouldn't be surprised if proper 6-hour snowboard clearing resulted in unusually high totals for this event given how exceptionally warm it was at the surface.

With this being said, should I forego the 6" rule, and measure some other way at certain temps? I've always done the 6 hour thing, but when I read this I have my doubts for certain temps.

[CT Rain]

i don't think there is a chance BDL came within 4" of 20"...that total sticks out like a sore thumb. Compaction with this type of heavy wet snow is going to be a lot less than Feb 06 fluffy dendrites.

What about melting? And yes if I had to guess I'd say they got 15"

[CoastalWx]

I don't know if melting played a big part. I think once a slushy layer is established, it's a little more difficult to melt a significant amount ( I mean greater than 2"). I'd say the ground was pretty cold already given antecedent conditions and earlier snow.

[Damage In Tolland]

What about melting? And yes if I had to guess I'd say they got 15"

No way 11-12 tops

[snowman21]

With this being said, should I forego the 6" rule, and measure some other way at certain temps? I've always done the 6 hour thing, but when I read this I have my doubts for certain temps.

If it's above 32, and especially if you're at 34 and 35 like a lot of places were when it was snowing during this storm, you should measure as frequently as you can. The six hour rule only applies to clearing the measurement surface and not the frequency of measurements. The maximum snow depth since the last time you cleared the surface is your snowfall for that period even if your surface is just wet (i.e. all the snow melted).

[CT Rain]

I don't know if melting played a big part. I think once a slushy layer is established, it's a little more difficult to melt a significant amount ( I mean greater than 2"). I'd say the ground was pretty cold already given antecedent conditions and earlier snow.

Yeah good point. If you say 2" is max you can lose from melting and 1" from compaction you're looking at a 3" inflation by clearing every 6 hrs. With a max depth of maybe 14" you could conceivable have 17" at BDL.

[CT Rain]

If it's above 32, and especially if you're at 34 and 35 like a lot of places were when it was snowing during this storm, you should measure as frequently as you can. The six hour rule only applies to clearing the measurement surface and not the frequency of measurements. The maximum snowfall depth since the last time you cleared the surface is your snowfall for that period even if your surface is just wet (i.e. all the snow melted).

How much melting/compaction can you reasonably expect in an 18 hour storm and you measure depth at the end as opposed to clearing a snow board?

[Cold Miser]

If it's above 32, and especially if you're at 34 and 35 like a lot of places were when it was snowing during this storm, you should measure as frequently as you can. The six hour rule only applies to clearing the measurement surface and not the frequency of measurements. The maximum snow depth since the last time you cleared the surface is your snowfall for that period even if your surface is just wet (i.e. all the snow melted).

Got it. Thanks.

[Damage In Tolland]

665k out of power for CL&P - closing in on Irene, heavy heavy damage. Basically the whole northern 1/3 of the state is without power, Blizz ftw.

TollandKev Kevin Once in a lifetime Ocotber storm. Damage will be vast and widespread17 hours ago Favorite Retweet ReplyTollandKev Kevin Prepare for death and destruction. This is a life threatening situation17 hours ago

EDIT: Forgot this one

TollandKev Kevin Prep for extended power outages. Irene esque. Yes very possible28 Oct

Good call by kev.

If only CL&P had followed me on Twitter. They know who i am I am sure of that from my Tweets

[Cold Miser]

If only CL&P had followed me on Twitter. They know who i am I am sure of that from my Tweets

lol - I doubt anyone from CL&P is holding tight, waiting on the next tweet from you.

. . . Although you do bring up an interesting aspect of that technology that could be very useful to companies like that. Maybe there needs to be money spent on infrastructure/ or at least people to monitor people to some degree, although weeding out the useless info may be tough as I'm sure there are some who would make something out of nothing - crying wolf so to speak.

[CoastalWx]

Yeah good point. If you say 2" is max you can lose from melting and 1" from compaction you're looking at a 3" inflation by clearing every 6 hrs. With a max depth of maybe 14" you could conceivable have 17" at BDL.

Well that's just a ball park figure in my head with some reasonable deduction I guess. I don't have the evidence to back it up, but if they indeed used some sort of a non-asphalt surface...I don't think melting would have been that bad.