Snow Depth Days
of the Northeast: 2019-2020

The season in review

Welcome to the new snow season. Nothing remarkable happened in November. December got off to a great start with a big snowstorm that got cross country ski sites in southern NH and MA excited. However, a couple of heavy rains and temperatures in the 40s washed it all away. A mid-month storm melted in 50 degree weather, but snow in the closing days of the month helped downhill ski areas have a decent holiday week.

January brought rain that washed my snow away, then more rain and a January thaw with temperatures in the 60s for me and 70s for Boston. A couple of minor storms mid-month restored snow cover again, but only until the end of the month. Cold air wasn't completely missing, I had a sub-zero morning in both December and January (and a 0.1°F morning).

The Canadian Maritime provinces often get a lot of snow, but this winter brought immobilizing snow to St. Johns. I haven't kept up with their season, but a storm that's missing us now in early February will bring them a lot more snow.

Here, February brought below average snowfall, a fair amount of rain, and another break in the snow cover. 2015/2016 in Penacook had less. I wonder how they did, I might check a Canterbury CoCoRaHS site. Overall, while it was warm, three above 50°F days were more than offset by five sub-zero lows. Two were cold enough to shut down my mini-split heat pump.

March (and April and May) featured bare ground for all but a few days. The only decent snowstorm was 6", and most of it melted the first day - I never bothered to run the snowblower.

May featured a polar outbreak that impacted most of the eastern US (and a warm ridge in the west that balanced things out). I had rain that changed to a little snow on May 9th. 43 years before, I lived in Massachusetts and enjoyed their biggest ever May snow storm, see 40 Years Ago: Massachusetts Snags a Memorable Snowfall in May Storm.

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 23.3 111 4 24 1.4 0 2.3 1 3.1 3
Fairhaven MA 0.1 0 12.4 24 2.8 3 0 0 1.5 2
Pepperell MA 0.1 0 36 195 7.9 87 6.1 24 9.2 8 3.2 0
Bow NH 0.5 0 23.9 132 9.4 172 10.9 218 10 64 1.1 0.5
Bristol NH 4.2 4.1 20.2 73 17.1 224.5 14.8 298.5 7.6 30.5 0.7 0.2
Sutton Mills NH 2.1 2.5 19.9 75.5 10.3 73 13 135.5 7.5 9.5 0.6 0.5 0.5 0.5

2019-2020 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 34.1 139 4.1
Fairhaven MA 16.8 29 1.7
Pepperell MA 62.5 314 5.0
Bow NH 55.8 586.5 10.5
Bristol NH 64.6 630.8 9.8
Sutton Mills NH 53.9 297 5.5

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.) The University of Vermont has graphs of snow depths at Stowe through many seasons.

Last update: 2020 November 5
Ric Werme

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