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NOAA Nullifies 2017’s ‘Lake Effect’ Snowfall Records In Western Pennsylvania

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• Erie, Pennsylvania, recorded record snowfall in December 2017, but now those records are nullified.
• Weather experts told NOAA they found serious problems with how snowfall was measured at Erie Airport.
• NOAA agreed with the experts’ recommendations and reinstated older snowfall records set in 1958 and 2010.

It turns out Pennsylvania didn’t break snowfall records in December 2017, according to the National Oceanic and Atmospheric Administration (NOAA). And it was, at least partly, because of a traffic cone.

NOAA on Wednesday approved a panel of weather experts’ recommendation to invalidate 24-hour and monthly snowfall records supposedly set in Erie, Pennsylvania, in 2017.

Erie recorded a record-setting 50.8 inches of snowfall around Christmas Day 2017, and a record maximum monthly snowfall of 120.9 inches for the month. In total, Erie reportedly accumulated 191.5 inches of snow last winter season, but those figures are being disputed.

A State Climate Extremes Committee not only found problems with snowfall measurements taken by observers at the Erie Airport, but also the possibility of “systematic error” in the way snow accumulation was measured throughout winter 2017.

“Based upon this documented body of evidence,” the committee recommended NOAA “continue to recognize the 38 inch, 24-hour snowfall record from 20 March 1958 in Morgantown, PA and the 117.8 inch monthly maximum snowfall in Laurel Summit, PA during February 2010” as daily and monthly records.

Let’s be clear: Erie got a lot of snow owing to the so-called “Lake Effect” caused by cold air moving across warm lake water. Lake Erie’s low ice coverage played a role in allowing snow to cascade during December 2017.

But while Erie might have gotten a lot of snow, weather experts had doubts whether or not the lake town saw record-setting snow. For starters, snow observers at Erie’s airport reported way more snow than nearby areas.

“Snowfall reported by other observers in the Erie metropolitan area near the airport location reported 18 to 22 inches less snowfall over the 24-hour period in question,” the committee wrote to NOAA. “Stations which were closely examined were within 2 to 9 miles of the Erie Airport.”

The committee also noted “the comparison of snowfall measurements to snow depth at the Erie Airport consistently illustrated lower snow depth amounts than one would expect to see, given the high snowfall rates.”

Basically, poorly trained observers used the snowfall measurement equipment in ways that compromised the reliability of their observations. Pennsylvania State University’s Weather World noted:

Summary of questionable measurement practices during the big December 2017 snow in Erie, PA (records nullified by the State Climate Extremes Committee). Full report: https://t.co/SwiFXaLj9m pic.twitter.com/Ncoo0spauX

— Weather World (@WeatherWorldPSU) August 22, 2018

“Even compared with the neighboring observers, the snowfall and snow depth characteristics varied enough between these observers and the Erie Airport measurements to cause questions about observing practices,” the committee told NOAA.

Measuring snowfall can be tricky. Government guidelines require trained observers to measure snowfall accumulation with “snow boards,” which can sometimes just be square pieces of plywood painted white.

The snow board should be placed somewhere it’s not likely to be disturbed, then measured and wiped clean at regular intervals once snow starts to fall. The Washington Post noted problems with using a snow board to measure snowfall in D.C. in 2016.

When snow hit D.C. that year, “the board was buried and the observer could no longer locate the board,” WaPo reported, noting the observer “took multiple snow depth measurements and averaged them.”

“This is what was reported to the National Weather Service; it wasn’t snowfall, but rather snow depth,” WaPo noted.

In the case of Erie, the “[s]now depth measurements at the airport appear to under-represent the snowfall amounts and are not consistent with that of the other local snow observers.”

“In addition, after investigation of other snow events at the Erie Airport throughout the 2017-18 snow season, the [committee] compared reported snowfall and snow depth measurements and noticed a similar pattern,” the committee found. “This cast a shadow of a doubt on what may be either an overestimate for snowfall or some systematic error in under-representing snow depth.”

“The sub-committee reviewed data from the entire snow season and determined that snowfall observations for the Erie Airport during March 2018 are also suspect and remain under review,” the committee found.

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