Notable September SnowfallsUPDATE (evening of June 26):
The first substantial snowstorm of the season has taken shape over the higher elevations of Idaho, Montana, and Wyoming. So far (as of Thursday evening September 26th) 18.0" has been measured at Silver Bow which is 6 miles SSE of Janney, Montana; 15.4" at Schwartz Lake, Idaho (elev. 8620') which is 27 miles NNE of Challis; and 12" at Togwotee Pass, Wyoming (elev. 9,658') about 12 miles east of Moran. September snow is not unusual for the Rocky Mountains but here is a short list of some September snowfalls across the countries that truly were amazing.Rocky Mountains
Since September snow is common in the higher elevations of the mountainous West, only low elevation snowfalls are noteworthy. Denver, Colorado’s greatest September snowfall was 16.5” on September 27-28, 1936. Snowflakes have been observed in Denver as early as September 3rd in 1961 when it snowed 4.2” at Stapleton Airport (it was 94° in Denver on that date this year!). On Labor Day 1961 (September 3rd) 4”-12” of snow blanketed the Denver Metro area, the city’s earliest measurable snowfall on record.
NBS News Denver Channel 9.
Colorado Springs’ greatest single snowstorm on record (for any month) took part partially in September when 34.1” fell between September 28-October 3, 1959. Salt Lake City, Utah’s first measurable snow was when 2.2” fell on September 17, 1965. Snow in the Sierra Nevada during September is rare but not unheard of. Just last Saturday (September 21st) 5” fell at elevations above 8000’. Reno, Nevada (at 4,500’) measured 1.5” on September 29, 1982, its earliest such on record. September snow at high elevations in the Cascades of Oregon and Washington are almost annual occurrences.Upper Midwest
Perhaps the most anomalous September snowfall on record for the Midwest was that of September 25-27, 1942. Widespread accumulating snow fell as far south as central Illinois with peak amounts occurring in Minnesota at Sauk Center with 9.0”, 4.0” at several locations in Iowa (including at Millerton near the Missouri state border), 6.3” at Deerskin Dam, Wisconsin, 8.0” at Dukes, Michigan, and an amazing 2.5” in Monmouth and Kankakee, Illinois as well as 4.0” in LaPorte and Wheatfield, Indiana.Snowfall accumulations across the Upper Midwest on September 25-27, 1942.
Map from NWS-La Crosse.New England and New York
Aside from the very highest peaks, like Mt. Washington and Mt. Mansfield, significant September snow in New England is extremely rare. Burlington, Vermont’s earliest measurable amount occurred on September 29, 1992 with just 0.1”. Looking back into the old records, however, there appears to have been a substantial snowstorm in the Lake Ontario and Finger Lake’s regions of New York State and the highlands of western New England on September 20, 1804 although actual depths are not mentioned. Both 1835 and 1836 experienced snowfalls in September. In 1835 6-12” accumulated over Franklin County, Vermont (near the Canadian border) on September 30th. In 1836 a widespread snow events affected New York State on September 28-30 with 2” measured in Syracuse and 1” in Rochester. Snow was reported in the Berkshires of Massachusetts and the Catskill mountains in southeastern New York as well.
Below is a chart of the earliest observed measurable snowfalls from select cities across the U.S:
Christopher C. Burt