Snow Depth Days
of the Northeast: 2017-2018

The season in review

November was quiet, as was most of December except for some nice size storms on the 9th and 12th. Christmas Day brought a regime change. After the biggest snow storm of the month, cold air blew in bringing sub-zero temps from through Jan 7th, except for the 26th (1.5°F) and 4th (1.8°F). Most of the rest of January was much warmer, with essentially three thaws, the first with a high temperature of 55.6°F on the 12th and six other days over 45°F.

February started cooler, but for most of the month every few days an air mass five degrees warm than the previous would arrive for a single day. I.e. the local peaks were 35, 40, 45, 50, 72(!), 48, and 61. By the end of the month my snow was gone. March headed in the opposite direction, the day after St. Patrick's Day was below freezing all day, the warmest day was the 28th, with 59°F, colder than February! Snow came back for a second season with snow cover from the 8th to 23rd.

April was also chilly with a lone Snow Depth Day on the 16th, but we finally exceeded the February high on the 24th with 74°F.

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
Fairhaven MA 6.7 15 11.5 41 1.2 8 14.8 40 2.8 3
Pepperell MA 0.1 0 15.8 121 18.6 172 13.3 15 46.9 184 4.1 2
Poland Spring ME 1.2 1 29.6 203 18.8 347
Bow NH 22.3 165.5 15.6 296 20.1 227 27.9 255 2.9 4
Bristol NH 2.3 1.9 28 216 13.3 374 23.2 349.5 22.7 131 4.2 5.6
Penacook NH 0.9 0.5 24.9 181 12.1 279.5 18 199.5 20.8 75 1.4 1
Mt. Mansfield VT 2 2 22.1 186 33.3 888 9 1231

2017-2018 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
Fairhaven MA 37 107 2.9
Pepperell MA 98.8 494 5.0
Poland Spring ME 49.6 551 11.1
Bow NH 88.8 947.5 10.7
Bristol NH 93.7 1078 11.5
Penacook NH 78.1 736.5 9.4
Mt. Mansfield VT 66.4 2307 34.7

Contributors

Name Location
Dennis Bollea Fairhaven MA
Wayne Cotterly Poland Spring ME
Robert Davitt Deerfield NH
Steve Gunn Bristol NH
Jim Hilt Bow NH
Andrew Plona Collinsville CT
Paul Venditti Pepperell MA
Ric Werme Penacook 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 consistantly. (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: 2018 May 6
Ric Werme

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