In January 2024, the mid-Atlantic region—including Philadelphia, Baltimore and New York City—saw plowable snow for the first time in 700 days. The mid-Atlantic has been the most severely affected by the lack of snow over the past decade, significantly driving climate averages down with the help of two nearly snowless winter seasons (2019-20 and 2022-23).
We’re coming out of another winter where many snow contractors were felled by another lackluster season. We have been knocked down this year in most markets.
The immediacy of the impact of yet another light winter makes it easy to forget that just three years ago many areas of the United States and Canada were blasted by two intense storms that left heavy snow, record-breaking ice and brutal cold in their wake.
But the concerns are real for snow contractors who are facing challenges presented by changing global weather patterns. Among the most frequently echoed concerns I hear are that a) winters aren’t as cold; b) there are shorter or even snowless winter seasons; c) we’re seeing more mixed events and ice storms; and d) lighter, fluffy snow is being replaced by heavier wet snow.
To help differentiate whether some of the changes observed by contractors may be due to climate change or are just part of normal swings associated with winter seasons, our WeatherWorks team reviewed thousands of weather records across the United States and Canada with a focus on Boston, MA; Philadelphia, PA; Columbus, OH; Denver, CO; Minneapolis, MN; Montreal, QB; Chicago, IL; and Washington, DC. Some of what we found validates what we’re hearing from the industry; other data debunks certain patterns that seem to have occurred; and yet other findings still leave us with more questions and research to do.
In some markets, there has been a notion that the snow season is becoming shorter, and when it does snow, it doesn’t last long. To determine if the snow season is becoming shorter, meaning less snow outside of December-February, we analyzed data and trends in the eight markets.
In all locations, we found that slightly more snow is occurring during the heart of winter with a decline in average snowfall amounts in the shoulder months (October-November and March-April). The one outlier was the Denver market, where the snow season seems to be growing and less of the annual snowfall is measured between December and February.
As you would expect, warming average temperatures result in more frequent marginal temperatures during winter events. That should, in theory, lead to more mixed events or "all snow" events with temperatures at or above 32°F. The data confirms that this has been true in most markets, particularly the ones that are warming the most. The exception has been in the Rockies, which has actually seen a slight tick down in the number of mixed events in the past 15-20 years.
More mixed and ice events. Mixed events, defined as events that had both snow and freezing rain, have slightly increased over the last 15 years. The greatest increase has been observed in the traditionally colder and snowier markets that are now seeing more marginal air in storms. Thus, the greatest increase in mixed events has been in the Minneapolis and Buffalo markets. The Interstate 95 corridor from Washington D.C. to Boston has seen a more subtle increase.
Climate change is certainly a concern for the future state of the snow and ice industry across the United States and Canada; however, winter weather and snowstorms will continue to occur in all markets. As of this writing I anticipate at least one more sizable event across the country by mid-April.
There have been many lean snow seasons in the past century, but they have always been balanced by a swing back to snowier periods. Even in a warming current state of the atmosphere, several markets have seen a slight uptick in snowfall totals.
We must sharpen our pencils, stay on top of current trends and become more creative and innovative on how we integrate these changes when responding to the needs of property owners. Winter variability is a normal occurrence and will continue to bring year-to-year volatility to certain snow markets. Although some markets may see a continuation of more mixed events and significant year-to-year swings, rest assured winter is here to stay.
Year-to-year volatility?
Year-to-year snowfall volatility, defined as the top 10 greatest changes in snowfall from one year to the next over the past 100 years, mimics temperature trends across North America. Cities such as Boston, MA, Washington, DC and Columbus, OH have seen 6-8 of their most volatile winters within the last 30 years. A normalized number should be only three occurrences. Meanwhile, through most of the Midwest and Rockies, there hasn’t been much correlation in recent years.
The takeaway is that areas in the Rockies, Northern Plains and upper Midwest are likely to experience somewhat normal year-to-year variability (1 extreme swing every 10 years); the mid-Atlantic and Northeast, however, are more certain to see bigger and more frequent year-to-year extremes with a significant swing up or down on average every 2-4 years.
Are winters getting warmer?
On a global scale, rising temperatures over the past 100 years are the most glaring effect of climate change. This not only includes warmer average temperatures but also fewer exceptionally cold days. As a result, many contractors are now observing a longer growing season. This has been most prevalent east of the Mississippi and all southern states where average winter (Dec-Feb) temperatures have been climbing.
Philadelphia, PA and Montreal, BC have seen six of their all-time highest yearly average temperatures within the last 10 years; and winter temperatures have been rising. Other snow markets in the Midwest and Rockies have seen either fairly consistent temperatures or even cooling trends. In Denver, for example, the average winter temperature during the last 30 years has actually cooled a bit. The same holds across much of the Northern Plains.
Is snow becoming heavier and wetter?
In most markets that we studied, there is a definite trend indicating an increase in snow falling at warmer temperatures. We reviewed the total number of hours in the last 20 winter seasons where snow fell when temperatures were above 32°F and the number of hours where snow fell at temperatures 25°F or lower.
Our findings were consistent in the eight markets we investigated, with one exception. The Denver market has actually seen a recent increase in the number of hours that snow falls at colder temperatures. This would mean more hours of fluffy snow and less of the wet, heavy snow that other markets are seeing.
Frank Lombardo is president of WeatherWorks, Inc. Data analytics for this story were compiled by Rob Reale, Simon Wacholz and Elijah Sumner. Learn more at www.weatherworksinc.com.