State of the snowpack / Streak ends at 48-50 days for those around Rt.78/80 and S

[Juliancolton]

Question for the experts here. I remember as a kid learning in school about sublimation of solids directly to liquid, and the example of losing snowcover despite temps well below freezing. To what extent is this true? For example, given a fluffy snowcover after a blizzard, if we had sunny with 15 degree high temps for a week, would snowcover dimish, excluding compaction?

It depends largely on the sun angle. Around the solstice, your losses to sublimation would be negligible, but this time of year you could lose up to 1/3" per day with the right conditions (a stiff surface wind, low humidity). That's the figure I've heard and tend to go along with, anyway. Compaction will have a far greater impact on fresh snowfall for the first couple of days.

 

Hopefully a met. will pop in and confirm the above figure.

[JERSEYSNOWROB]

Can you spot the south facing side of the street?? Hahaha Also, my dirty Jersey strip mall snow piles still holding on strong.

[uncle W]

Central Park reported no snow cover for yesterday...It's probably wrong...again...3" reported on 3/8...

[Isotherm]

Probably the primary reason why the snowpack is holding tough given its early March is the fact that this is NOT new snow. The snow remaining, for most people, has a very high water content due to the refreezing, thawing, rain absorbed, glaciating over again process that we've seen over the course of the 4-7 week period since late January. In other words the pack that remains is tough as nails and basically a sheet of ice. Much more difficult to melt off a high water content snow.

 

I remember the March 1st 2009 snowstorm which dumped 13.5" here, melted away in about 3-4 days, largely due to the freshness and lower water content.

 

So really the best case scenario for maintaining snow cover in March is to have a long-standing, hardy, high water content snowpack going into the month.

[Juliancolton]

Probably the primary reason why the snowpack is holding tough given its early March is the fact that this is NOT new snow. The snow remaining, for most people, has a very high water content due to the refreezing, thawing, rain absorbed, glaciating over again process that we've seen over the course of the 4-7 week period since late January. In other words the pack that remains is tough as nails and basically a sheet of ice. Much more difficult to melt off a high water content snow.

 

I remember the March 1st 2009 snowstorm which dumped 13.5" here, melted away in about 3-4 days, largely due to the freshness and lower water content.

 

So really the best case scenario for maintaining snow cover in March is to have a long-standing, hardy, high water content snowpack going into the month.

Many folks have one or more layers of sleet and/or freezing rain to add rigidity and insulation, as well. I wouldn't be surprised to see some of this stuff stick around through April 1, assuming no deluges and especially if this week's storm produces.

[Mikehobbyst]

Do any of you believe the 3/18-19 HECS threat from the ECMWF is real ?? Discuss why or why not ?  We'll have the mall piles through Flag day if we get the 19.2 inches forecast by the Euro for next week HECS.  We'll be sublimating like crazy with the 70 degree sun angle by then, even if the -EPO keeps going strong.  We'd be in the 55-60 degree range by June 1st,  even if the Polar Vortex is still stuck in Quebec for the next three months.

[Bobby]

Do any of you believe the 3/18-19 HECS threat from the ECMWF is real ?? Discuss why or why not ? We'll have the mall piles through Flag day if we get the 19.2 inches forecast by the Euro for next week HECS. We'll be sublimating like crazy with the 70 degree sun angle by then, even if the -EPO keeps going strong. We'd be in the 55-60 degree range by June 1st, even if the Polar Vortex is still stuck in Quebec for the next three months.

Asking if something that is produced by a computer based on algorithyms and data input is "Real" is really a waste question. Is it real? Seriously? No it's not unless you're a weenie of the Nth degree. Euro snow maps more than a week out? Really? Lol. 60 degree range by June 1st? Someone has watched The Day After Tomorrow WAY too many times lol

Thanks! Your posts are always good for a smile

[Juliancolton]

Do any of you believe the 3/18-19 HECS threat from the ECMWF is real ?? Discuss why or why not ?  We'll have the mall piles through Flag day if we get the 19.2 inches forecast by the Euro for next week HECS.  We'll be sublimating like crazy with the 70 degree sun angle by then, even if the -EPO keeps going strong.  We'd be in the 55-60 degree range by June 1st,  even if the Polar Vortex is still stuck in Quebec for the next three months.

Wrong thread

[JetsPens87]

Do any of you believe the 3/18-19 HECS threat from the ECMWF is real ?? Discuss why or why not ? We'll have the mall piles through Flag day if we get the 19.2 inches forecast by the Euro for next week HECS. We'll be sublimating like crazy with the 70 degree sun angle by then, even if the -EPO keeps going strong. We'd be in the 55-60 degree range by June 1st, even if the Polar Vortex is still stuck in Quebec for the next three months.

Flag Day?! Come on man. And we're not getting the Phantom hecs shown again by the euro at Day ten. For some reason or another this specific pattern doesn't want to do it and it's likely due to the time of year.

[uncle W]

it's amazing we had a plus NAO since January 21st give or take a day or two and that's when our snowpack started...

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao_index.html

[Juliancolton]

10.3"/3.5" OTG near where I measured 11.5"/3.6" on Friday, meaning I lost over an inch of depth in this weekend's sun and torch, but only 1/10th" of liquid equivalent, for ratios now at 2.9:1.

[snywx]

At 1pm today I had 11" throughout the property. Lost about 2" since Friday

[Zelocita Weather]

I'm calling the overall snow pack gone today/tomorrow in S Essex, probably at around 50% coverage or so now...49/50 days straight into mid March. Not bad...

[CSheridan12]

This is going to be a weenie question, but only because I don't think we ever learned this in school, and I've never investigated because I've only ever professionally been a met in Texas where snowpack is a non-issue, but how exactly do we measure snowpack for official record keeping? I look at my street today and the south-facing side of the street is pretty much fully melted where as my house faces north and we still have a good 4-8" in places. How do you incorporate shady sections and sunny sections of a field/yard when it comes to measuring the snowpack? When uncleW posted that chart at the top of the thread, i guess I'm curious where those numbers come from? I'm guessing central park, but where? in the sun? shade? next to the thermometer? do different people who do the measurements use different places? This just seems like a very difficult thing to objectively measure.

[rygar]

I am 10 miles north of 80 in West Morris and still have 10 or so inches left ... before today anyway!

[uncle W]

This is going to be a weenie question, but only because I don't think we ever learned this in school, and I've never investigated because I've only ever professionally been a met in Texas where snowpack is a non-issue, but how exactly do we measure snowpack for official record keeping? I look at my street today and the south-facing side of the street is pretty much fully melted where as my house faces north and we still have a good 4-8" in places. How do you incorporate shady sections and sunny sections of a field/yard when it comes to measuring the snowpack? When uncleW posted that chart at the top of the thread, i guess I'm curious where those numbers come from? I'm guessing central park, but where? in the sun? shade? next to the thermometer? do different people who do the measurements use different places? This just seems like a very difficult thing to objectively measure.

I don't know where they take the snow depth measurements...I just used the info on their climate data...At one time it was measured in tenths of an inch many years ago...I got the idea from an old 1973 weatherwise magazine that had an artical about Philadelphia having no snow that year...only traces...I basicily copied their foremat...some days have to be estimated because of missing data...I'm not sure if the same time was used for measuring snow depth in the past...I used anytime of the day for my totals...If it snows 1" and was on the ground but melted fast before the next depth measurement I counted it...If it snows 1" and is on the ground from pm one day to am the next I counted it as two days...I did it for all the years...The numbers aren't exactly 100% correct but a great guideline for snow depth for any givin winter...Central Park stopped taking snow depths from 1996 for ten years or so...I used LGA snow depth obs and estimated some days...It looks like they miss or don't report trace amounts at times for what ever reason...In past winters trace amounts were more on average...

[RU848789]

We reach 4 weeks of continuous snow cover on Tuesday, 2/18, which is a lock, as Tuesday is our first day up to 40F in a long time.  Beyond that, even if the subsequent week has a warm-up with several days in the 40s, I'd be amazed if we lost more than 1/2 to 2/3 of the snowpack, given how much liquid equivalent there is frozen into the snowpack and LE (or total mass) is much higher than it might be in some years where we had the same frozen depth as we have now (at least in most places).  FYI, here's a post I made last night in the obs thread about concerns over the snowpack melting last night with some rain; similar argument can be made about the snow mass being very large, such that full melting (sans a 60F snoweater rainstorm) will take quite a while.  And the analysis, below didn't include the snow from last night, plus we'll get some more tomorrow. 

 

People: even an inch of rain on top of about 2.5" liquid equivalent as snow/ice will largely be absorbed by that snowpack, although compression will be significant, making it appear a large part of the snow is "gone."  For example, I had ~8" of snowpack left before this storm that probably contained about 1.4" LE from the 1/21 (~3" left as of 2/3), 2/3 (8" of ~10:1 rato snow), 2/5 (2" sleet and 0.25" ZR for 0.85" LE) and 2/9 (2.5" of 15:1 ratio snow) snow/sleet/ZR events (it was very cold through that whole period, so I'm guessing maybe 1/3 of that melted), which were about 2.1" LE, overall. 

 

Add on today's 1.1" LE as snow/sleet and that gets me my 2.5" LE before the changeover this afternoon. I'm guessing I now have close to 3.5" LE in my snowpack, as the 1+" of today's rain was mostly absorbed.  Sure, in urban areas where much of the roads/parking lots were cleared today, the rain would mostly go down the drain - I'm talking about rain falling on a snowpack.  And when it goes down into the 20s tonight, that 3.5" LE snowpack will be cemented in place (with hopefully a few inches of fresh snow on top).   

 

 

As I've been saying, pretty sure we will still have several inches of snow on the ground by Sunday night, when winter returns. I just can’t imagine this very dense snowpack all melting. There’s about 3-4” of liquid equivalent still bound up in it and that’s the equivalent of 30-40” of snow (and snow melt is a function of snow mass, not depth, i.e., we have 30-40" of typical 10:1 ratio snow compressed into 10-12” snow/ice right now) and 30-40” of "typical" snow ain’t all melting from the next 2 days of temps in the 50s, even with some rain/fog. If it does, I’ll be flabbergasted. Should be a lot less snow, though, on the ground by the time it gets back below 32F on Sunday night - I'm guessing 2-4" left on my lawn.

 

I'm not a met, but I like to think the posts above demonstrate I know a little bit about analysis of a snowpack and projecting melting rates (chem engineers likely learn more about those topics, lol).  The two posts above were in response to many people saying the snowpack was going to be gone in a few days because of some warming and/or rain and I was certain we had at least a few more weeks to go.  Was pretty confident we'd last a lot longer than some were saying, given the incredible amount of liquid equivalent that was originally in this snowpack (4-5" LE estimated at its height, compressed into maybe 15" of snowpack when the melt began).  That kind of mass (and it's mass that is critical to snowpack melting rate, not depth) simply doesn't melt quickly and any rain that falls on it just gets absorbed and adds to the LE when the temps go back below freezing.

 

Anyway, it turns out that In Metuchen, today might be the day I'd have to say that, on average, less than 50% of the properties and open spaces remain snow covered.  However, my house, which is relatively shady, still has 2-4" of dense snow/ice nearly everywhere, except at the base of any trees and places where my footprints were - and the small park across the street is still 90% snow-covered, but our soccer field was 80% bare yesterday, marking the first day we've played soccer on Sunday since 1/19 (only explanation is it's a bit shadier across the street).  Great run - my house will reach 7 weeks tomorrow, but not sure if we make it past Wednesday, if it hits 50F+ with heavy rain. 

[RU848789]

In answer to questions on how to measure snowpack depth, here's what famartin posted in the Philly thread on this...

 

 

3.2. Snow Depth

 

Snow depth measurements are taken as long as there is snow on the ground. Determine the total depth of snow, sleet, or ice on the ground. This is a combination of snowfall (if snow has fallen during the observing period) and snow that was already on the ground. This observation is taken once a day at the scheduled time of observation with a measuring stick. Sometimes it is taken by measuring the total depth of snow on exposed ground at a permanently mounted snow stake.

 

3.2.1. Making the most accurate snow depth measurements

 

Very often, snow depth needs to be determined by using a measuring stick to take, and then average, several depth readings. This is generally done within 100 yards (300 feet) of the official observing location and is often necessary because snow depth can vary in the vicinity of an observing location due to shaded and non-shaded areas, and because wind-blown snow can create areas of greater and lesser depth*.

 

In addition, in hilly or mountainous terrain you will be faced with the situation where no snow is observed on south-facing slopes while snow, possibly deep, remains in shaded or north-facing areas. Under these circumstances, you should use good judgment to visually average and then measure snow depths in exposed areas within several hundred feet surrounding the weather station. For example, if half the exposed ground is bare and half is covered with 6 inches of snow, the snow depth should be entered as the average of the snow readings, or 3 inches.

 

• When, in your judgment, LESS THAN 50 PERCENT of the exposed ground is covered by snow, even though the covered areas have a significant depth, the snow depth should be recorded as a trace (T). Make a note of the range of depths of the remaining snow in the comments.

 

• When no snow or ice is on the ground in exposed areas within 100 yards (300 feet) of your normal observing location, record a “0”.

 

• When strong winds have blown the snow, take several measurements where the snow was least affected by drifting and average them. If exposed areas are blown free of snow while others have drifts, again try to combine visual averaging with measurements to record your representative value for snow depth. (noting that if more than half of the ground is snow-free only a trace should be reported)

 

* Measurements should not be taken from rooftops, paved areas, or other surfaces that are likely to be warmer than natural surfaces.

 

3.2.2. Properly reporting snow depth

 

When using a measuring stick, make sure the stick is pushed vertically into the snow until the bottom of the stick rests on the ground. Do not mistake an ice layer or crusted snow as ground. The measurement should reflect the average depth of snow, sleet, and glaze ice on the ground in areas not disturbed by human activities (e.g., no artificial piles of snow).

Be aware that measurements taken on grass can leave air space below the bottom layer of snow, particularly early in the season and when there was no previous snow on the ground. Measuring all the way to the ground can inaccurately inflate the snow depth amount. If you suspect this may have occurred, carefully clear a small patch of snow away so you can see the snow layer on top of the grass. Measure from the bottom of the snow layer to the top of the layer. You may have to repeat this in several areas to obtain a representative snow depth.

 

After you have made your snow depth measurements, average the measurements to obtain a single number for snow depth. Report snow depth to the nearest whole inch, rounding up when one-half inch increments are reached. For example: 0.4 inches of snow on the ground should be reported as a trace (T), 1.3 inches should be reported as 1 inch, 3.5 inches should be reported as 4 inches. Be aware that when taking measurements over grassy surfaces that air space might be present within the grass. If necessary reduce the snow depth reading by an appropriate amount.

[Stormlover74]

My backyard is about 80% bare now with just some snow/ice in shaded areas. Front yard also mostly bare but yards across the street still completely snow covered.

[IsentropicLift]

Snow pack still holding strong here although lots of grass showing now.

[HailMan06]

The snowpack is going to take a major hit over the next couple days.

[Isotherm]

Pretty much everywhere is bare now, but I was able to find a deeply wooded area in Colts Neck that still has decent coverage as of today:

 

[forkyfork]

The snowpack is going to take a major hit over the next couple days.

it's march and we're not in new england

[jm1220]

The snowpack is going to take a major hit over the next couple days.

It's been gone here for weeks now, so w/e in my case. Bring on spring-maybe the dark ice piles in the parking lots can finally be washed away by rain.

[Keith O]

55 here at 11AM which was the forecast high.  Thinking low 60's is a good bet...

[Zelocita Weather]

Looks like the line is roughly from N/C Bergen, W Passaic, Morris, NW Somerset or so....south of that its largely gone and by Thursday prob all in NJ (except for maybe Sussex) will be wiped out...

[HailMan06]

It's been gone here for weeks now, so w/e in my case. Bring on spring-maybe the dark ice piles in the parking lots can finally be washed away by rain.

I still have ~45% snowcover. Thinking it'll be reduced to piles later today.

[threeyoda]

A lot of melting here in Pompton Lakes today, but it is absolutely gorgeous out. Bring on spring!

[CSheridan12]

In answer to questions on how to measure snowpack depth, here's what famartin posted in the Philly thread on this...

This was fantastic, thanks man.

[NorthShoreWx]

We still had more than 50% coverage this morning, but I'm sure it will be a trace by tomorrow, if not already.  60 degrees and thaw continuing as of 15 minutes ago (12:30PM)