![]() ![]() The poles on either side allow the snowboard to be found in case of very heavy snow between observations. An official snowboard, as pictured in the National Weather Service pamphlet Snow Measurement Guidelines for National Weather Service Snow Spotters. Kelsch’s description of these in his writeup).įigure 3. or 7 p.m.).Īt some point (and this is the problem with my data: that this “point” in time varied from site to site between the 1950s and 1990s), snowboards came into use (see Mr. is roughly 12:1 or 13:1, and that ratio can vary greatly from place to place and storm to storm, even within a single storm.Īt some point-and that point in time was different among the various weather observation sites-actual snowfall began to be measured using a stick-like ruler, with the snow measurements made either at the end of each snowfall or at one or more regular times each day (e.g., at 7 a.m. As it turns out, the average ratio for the contiguous U.S. An article authored by Matt Kelsch of NCAR/UCAR and official COOP observer for Boulder, Colorado, explains how in the oldest of snow records (mostly predating 1950) a simple 10-to-1 snow-to-liquid ratio was often used to estimate the snowfall (i.e., 1” of melted precipitation = 10” of snow). Map of the 40 sites used in my data table.Īs noted in my previous blog, the methods of snow measurement in the U.S. I’ve made an attempt to distribute the sites in a geographic manner that represents all of the various regions of the contiguous U.S. For comparison’s sake, the latest official 30-year POR average (1981-2010) and the snowiest and least snowy single seasons are also included (bottom). ![]() Each city’s snowiest decade is highlighted in red and its least snowy decade in blue. ![]() This makes it easier to compare changes over time for cities that are within more or less the same regional areas. The city list is arranged in a general east-to-west and north-to-south pattern, following general regional areas such as “along the east coast”, Ohio Valley, Midwest, Plains, Rocky Mountains, and far West. since the season of 1900-1901, up to and including the season of 2018-2019 (top). Average decadal snowfall for 40 significant sites in the contiguous U.S. The dataīefore discussing the trends and reliability of the data, below is the table, based on reports culled from the National Weather Service NOWData website.įigure 1. For instance, in the high mountain areas of the West there are virtually no sites with a continuous period of record (POR) back to 1900, aside from Flagstaff, Arizona Donner Summit in the high Sierra of California and Red Lodge, Montana (which I did not include because of its obscurity). There is no complete record for Nashville, Tennessee Roanoke, Virginia Sheridan, Wyoming and Seattle, Washington, among other cities that would seem to be obvious choices. I only included places that see winter snowfall regularly (i.e., in most years), meaning along and north of a line from North Carolina through Tennessee, Oklahoma and the mountainous regions of the West.Ī constraining factor in choosing the sites is that they must all have a continuous monthly snowfall record dating back to at least 1900, something that a surprisingly few do. So, as a follow-up to that, I decided to look at how much snow has actually been measured decade by decade at 40 different cities/sites across the contiguous U.S. The basic conclusion was that no one really understands much about this. In the conclusion to that blog, I wrote a bit on how climate change may be affecting snowfall in the United States. In my previous post, I looked at record snowfalls for all the states and several cities for various periods of time (24 hours, monthly, etc.). Image credit: Bob Henson.Īs anyone who has followed my blogs for WU over the past ten years has no doubt noticed, I am always interested in the actual data-derived records so far as weather events are concerned. 25-26 gave Boulder 22” of snow and 1.47” of liquid equivalent-which shows that the 10-to-1 snow-to-liquid ratio that was often used to extrapolate snowfall amounts decades ago can seriously underestimate snow totals. Above: A snow-covered street in Boulder, Colorado, on Nov. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |