32-Year Winter Storm Archive Complete

[Ginx snewx]

18 minutes ago, IrishRob17 said:

You mentioned "it was the 24 hour method"? How are you measuring these days, do you clear the board ever 6 hours? It's the constant debate whether we should clear every 6 or 24 hours and in the last NWS guidance @NorthShoreWx and I have found the 6 hour method is out for hobbiests like ourselves. 

Every 6

[NorthShoreWx]

5 hours ago, Ginx snewx said:

Totally under measured as it was the 24 hr method.

It's not technically an under-measurement if the observer is following the standard that they are supposed to.  The problem is that there are different standards for different types of observers.  I'll never beat ISP in a big storm unless they rain and I don't because they are supposed to wipe the board every 6 hours and I am not.  In the most recent storm, ISP reported 13.2" and I had 11.4".  I don't think they had more snow than I did (plus we snowed heavily a little longer before changeover to sleet), but both measurements can be technically correct.

I suspect the once in 24 hours max depth standard might be designed to make it easier for observers, plus in some instances (not all) it is a more accurate way to portray the snowfall.  Wiping the board more often makes sense for airports because it relates more directly to wiping the snow from runways.  It is frustrating that we can't do apples to apples comparisons, especially when doing projects like The 4 Seasons is doing.

For my money, snow depth and LE of the snowpack are the best way to compare between sites.

[CoastalWx]

@The 4 Seasons 

 

[IrishRob17]

21 minutes ago, NorthShoreWx said:

It's not technically an under-measurement if the observer is following the standard that they are supposed too.  The problem is that there are different standards for different types of observers.  I'll never beat ISP in a big storm unless they rain and I don't because they are supposed to wipe the board every 6 hours and I am not.  In the most recent storm, ISP reported 13.2" and I had 11.4".  I don't think they had more snow than I did (plus we snowed heavily a little longer before changeover to sleet), but both measurements can be technically correct.

I suspect the once in 24 hours max depth standard might be designed to make it easier for observers, plus in some instances (not all) it is a more accurate way to portray the snowfall.  Wiping the board more often makes sense for airports because it relates more directly to wiping the snow from runways.  It is frustrating that we can't do apples to apples comparisons, especially when doing projects like The 4 Seasons is doing.

For my money, snow depth and LE of the snowpack are the best way to compare between sites.

If I did the every 6 hours thing my 38.5" YTD would be closer to 50".

[Ginx snewx]

2 minutes ago, IrishRob17 said:

If I did the every 6 hours thing my 38.5" YTD would be closer to 50".

Do you want to measure the amount of snow that fell or just compacted snow. 24 hrs with say a 8 hrs snow event.  I measure 6 and then 2. The next day after either melting or drying out your measure could for arguments sake be 5 inches. That's what often happened in the record book. So how much snow actually fell . I say 8

[IrishRob17]

21 minutes ago, Ginx snewx said:

Do you want to measure the amount of snow that fell or just compacted snow. 24 hrs with say a 8 hrs snow event.  I measure 6 and then 2. The next day after either melting or drying out your measure could for arguments sake be 5 inches. That's what often happened in the record book. So how much snow actually fell . I say 8

Agreed, if one waits hours after its done to measure its going to be off. You always measure at the end of the event, so in that case I measure after 8 hours because the storm is over. You also need to measure at the point there's a change in precipitation type. I'm a snowpack guy anyway so what truly matters to me is what is at the stake each day. 

[Ginx snewx]

29 minutes ago, IrishRob17 said:

Agreed, if one waits hours after its done to measure its going to be off. You always measure at the end of the event, so in that case I measure after 8 hours because the storm is over. You also need to measure at the point there's a change in precipitation type. I'm a snowpack guy anyway so what truly matters to me is what is at the stake each day. 

Excellent 

[dendrite]

36 minutes ago, IrishRob17 said:

Agreed, if one waits hours after its done to measure its going to be off. You always measure at the end of the event, so in that case I measure after 8 hours because the storm is over. You also need to measure at the point there's a change in precipitation type. I'm a snowpack guy anyway so what truly matters to me is what is at the stake each day. 

Clearing every 6hrs is a nice interval so that places that get a lot of high ratio snow…like upslope areas and LES..don’t get penalized by compaction.

Take BUF in late Dec 2001.

24th
starting 6z depth 0”
New snow 20.5”
ending 5z depth 18” (+18”)

25th
5z depth 18”
new snow 4.9”
ending 0z depth 18” (0”)

26th
12z depth 18”
new snow 8.0”
6z depth 25” (+7”)

27th
6z depth 25”
new snow 21.9”
6z depth 33” (+8”)

28th
6z depth 33”
new snow 26.2”
20z depth 44” (+11”)
0z depth 41” (or +8”)
12z depth 38” (or +5”)

That’s 48.1” in the final 2 days with only 13” to 19” depth gain depending on when you caught the last depth measurement.

Imagine it snowing hard enough to produce 26” new with 6 hourly clearings, but it only goes in the books as 5” the next morning because of compaction? 

[IrishRob17]

10 minutes ago, dendrite said:

Clearing every 6hrs is a nice interval so that places that get a lot of high ratio snow…like upslope areas and LES..don’t get penalized by compaction.

Take BUF in late Dec 2001.

24th
starting 6z depth 0”
New snow 20.5”
ending 5z depth 18” (+18”)

25th
5z depth 18”
new snow 4.9”
ending 0z depth 18” (0”)

26th
12z depth 18”
new snow 8.0”
6z depth 25” (+7”)

27th
6z depth 25”
new snow 21.9”
6z depth 33” (+8”)

28th
6z depth 33”
new snow 26.2”
20z depth 44” (+11”)
0z depth 41” (or +8”)
12z depth 38” (or +5”)

That’s 48.1” in the final 2 days with only 13” to 19” depth gain depending on when you caught the last depth measurement.

Imagine it snowing hard enough to produce 26” new with 6 hourly clearings, but it only goes in the books as 5” the next morning because of compaction? 

This is always an inteesting discussion, do you clear every 6 hours?

[dendrite]

Just now, IrishRob17 said:

This is always an inteesting discussion, do you clear every 6 hours?

Always? No. I try to, but sometimes I go 8 or 12. I will extend it sometimes so that I can clear at midnight to get a daily snow and liquid amount.

[CPcantmeasuresnow]

1 hour ago, IrishRob17 said:

Agreed, if one waits hours after its done to measure its going to be off. You always measure at the end of the event, so in that case I measure after 8 hours because the storm is over. You also need to measure at the point there's a change in precipitation type. I'm a snowpack guy anyway so what truly matters to me is what is at the stake each day. 

The one difference I would note and I'll use the last storm as an example. When I cleared the board at 10pm I recorded 15.8 inches depth as the snow had ended. The next morning there was another 0.5 so I added that for a storm total of 16.3. I'm sure if I measured depth that morning it was probably closer to a 15 inch depth. 

[NorthShoreWx]

2 hours ago, Ginx snewx said:

Do you want to measure the amount of snow that fell or just compacted snow. 24 hrs with say a 8 hrs snow event.  I measure 6 and then 2. The next day after either melting or drying out your measure could for arguments sake be 5 inches. That's what often happened in the record book. So how much snow actually fell . I say 8

For the 24 hour measurements, the snowboard is only wiped once per day, but the greatest depth during that period is recorded as the snowfall.  If the snow on the board reaches a depth of 8" and then settles to 5", the amount of snowfall reported is 8"

I am not philosophically opposed to measuring and clearing the board every 6 or 12 hours, but the problem is that there are multiple prescribed standards which give rise to discussions like this.  I don't think there are any easy answers.