Snow Depth Days
of the Northeast: 2020-2021

The season in review

Welcome to the new snow season. October brought a little snow and a near record cold night. We actually had less snow in November, a rather dry and warm month. The last day of the month featured a rain storm that bought more rain than the rest of the month.

One brief storm in December made up for all of last year. Sutton was a little south of the main snow band for a storm that started early on the 17th. It ended only 13 hours later. At 0700 I had 15.2" of fluffy snow on the snow board. When the snow stopped, I had 12.0" inches more. 27.2" total. New London, just north west had 36", Croydon had 46". I didn't realize just how historic this was until I reviewed my records from Penacook and found the biggest storm there was only 18.5".

Various other superlatives:

On the 17th, I had my first sub-zero temperature of the season. A week later on Christmas Eve and Christmas Day, nearly two inches of rain and temperatures up to 56°F melted nearly all of the snow. Snow cover managed to limp to the end of the month except where rain pooled on the frozen or saturated ground and melted all the snow.

January was, in a word, blah. Okay, annoying blah. I recorded an impressive nine snow events. However, six had less than 1.0" of snow and the biggest was only 2.4". There was neither very cold weather nor a January thaw, but we did eke out a sub-zero morning on the last day, -1.0°F. Several days got above freezing, but none reached 40°F.

February was similar, we nearly went below 0°F on the first, and three lows were 1.7°F. All the lows were below freezing. Four days got above 40°F. For nearly all of the month we had about a foot of snow and ice on the ground. Similar to January, we had several (eight) snow events, but overall more than twice the snow, the biggest snow falls were 5.1" and 7.5". Parts of Massachusetts got more snow than New Hampshire.

March was a good month for snow haters. Last year I had more snow in each of March, April, and even May than the 0.3" this March. We had warm weather, with eight days above 60°F and two above 70°F.

There wasn't much to say about April other than its 2" of snow was more than March this year. It was welcome though, as my neighbor hadn't had a chance to burn his brush pile. Snow cover brings a lot of safety to that task, important as we hadn't had much precip of any sort. It gave me a chance to a couple cart loads of my brush too.

Daily/Monthly Data

The following table summarizes the snow fall and depth days from sites that are posting that data on local weather observations mail lists and a couple others. If people also prepare Web pages for daily information for their site, I'll include links to them. Cells under the "snow" column are the snowfall for the site in that month, under "SDD" are the depth days for the month.

Location October November December January February March April May
Snow SDD Snow SDD Snow SDD Snow SDD Snow SDD Snow SDD Snow SDD Snow SDD
Ashland MA 5.5 8 0 0 16 83 7.3 18 31.9 275 0 2 0.9 0
Fairhaven MA 0.2 0 0 0 6.5 20 4.3 14 14.1 67 0 0 0 0
Pepperell MA 4.2 6 0.1 0 18.1 101 7.8 21 25.5 253 0.1 43 3.1 2
Bow NH 1.6 1 0.2 1 30 193 6.1 170 23.7 346 0.1 224 0 0
Bristol NH 1.8 1.8 0.1 0 30.4 146.2 9.3 66.5 25.2 298 0.6 105 0 0
Sutton Mills NH 1.6 1.2 0.4 0.4 29.1 141 9.1 81.5 23.9 330.5 0.3 128.5 2 1.5

2020-2021 season to end of last month

The persistence quotient is lower than the ultimate value if there is still snow on the ground at the site. This data will be updated each month.

Location Snowfall Depth Days Persistence
Quotient
Ashland MA 61.6 386 6.3
Fairhaven MA 25.1 101 4.0
Pepperell MA 58.9 426 7.2
Bow NH 61.7 935 15.2
Bristol NH 67.4 617.5 9.2
Sutton Mills NH 66.4 684.6 10.3

Contributors

Name Location
Dennis Bollea Fairhaven MA
Steve Gunn Bristol NH
Jim Hilt Bow NH
Jot Ross Ashland MA
Paul Venditti Pepperell MA
Ric Werme Sutton Mills NH

Credits

Jim Corbin, a meteorologist from Rhode Island, proposed the concept of both snow depth days and the persistence quotient, but he didn't have good names for them.  After a bouncing around various ideas, I came up with Depth Days.  It seems to fit into colloquial speech well, e.g. "When mired in the Depth Days of February, she thought fondly of the Dog Days of August." Of course, none of us snow lovers would ever think that. I picked Persistence Quotient while putting this page together, we'll see how it wears with time.

Musings

I think depth days is a great statistic, and I'm surprised that it is catching on slowly outside of the NE Weather Spotters mail list. I never expected that the NWS would embrace it quickly, but I had hoped that TV meteorologists would start using it, in monthly summaries, if nothing else. It would be nice if ski areas would use it, but they may not wish to if they are not likely to be #1 consistently. (And if only one area reports depth days, it would not be a good comparative statistic.)

Last update: 2021 May 5
Ric Werme

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