Is This Snowstorm Normal? A Guide to December Snowfall

When a major snowstorm blankets your town in December, it’s easy to wonder if you’re living through a historic event or just a typical winter day. This guide helps you understand how meteorologists measure storms and compare them to historical averages, giving you the tools to put any winter weather event into perspective.

Understanding the "Average" December Snowfall

Before we can compare a single storm, we first need a baseline. When meteorologists talk about “average” or “typical” snowfall, they are usually referring to climate normals. These are 30-year averages of weather data calculated by organizations like the National Oceanic and Atmospheric Administration (NOAA). This long-term view helps smooth out yearly fluctuations, giving us a reliable picture of what a location’s climate is usually like.

However, an “average” can be a bit deceiving. A city’s average December snowfall might be 10 inches, but this could be the result of a few Decembers with massive blizzards and many more with very little snow. It’s rare for a month to hit the average exactly.

To see how much this varies, let’s look at the average December snowfall for a few major U.S. cities known for their winter weather:

• Buffalo, New York: Averages around 27 inches of snow in December, largely thanks to lake-effect snow from Lake Erie.
• Minneapolis, Minnesota: Typically receives about 11.5 inches of snow throughout December.
• Denver, Colorado: The Mile High City averages around 8 inches for the month.
• Anchorage, Alaska: Experiences significant winter weather, with a December average of about 19 inches.

As you can see, what’s considered “normal” snowfall depends entirely on where you live. A 10-inch storm would be a major event in Denver but might be just another Tuesday in Buffalo.

How to Compare a Storm to the Average

To accurately assess a winter storm, meteorologists look at several key factors. You can use these same metrics to understand the weather in your area.

Key Metrics for Measuring a Storm

1. Total Snowfall Accumulation: This is the most straightforward measurement. It’s simply the total depth of snow on the ground after the storm has passed, measured in inches or centimeters. You can find official totals from your local National Weather Service (NWS) office.
2. Snowfall Rate: This measures how intensely the snow is falling, usually in inches per hour. A storm with a rate of 2 to 3 inches per hour is considered very heavy and can create dangerous travel conditions quickly, even if the final accumulation isn’t a record-breaker.
3. Snow-to-Liquid Ratio (SLR): Not all snow is created equal. The SLR tells you how much water is in the snow. A typical ratio is 10:1, meaning 10 inches of snow melts down to 1 inch of water. However, cold, dry air can produce light, fluffy powder with a ratio of 20:1 or higher. Conversely, warmer, wetter storms create heavy, “heart attack” snow with a ratio closer to 5:1. This ratio dramatically affects how a storm feels and the impact it has.

A Simple Step-by-Step Comparison

1. Find Your Storm’s Total: Once a storm is over, check the NWS website or a trusted local news source for the official snowfall total in your specific area.
2. Find Your Monthly Average: Use NOAA’s Climate Data Online portal or a simple search for “[Your City] average December snowfall” to find the 30-year normal.
3. Make the Comparison: How does the single storm’s total stack up against the entire month’s average? If one storm drops more snow than you typically get in all of December, you’ve likely experienced a significant weather event.

Putting It in Context: Famous December Storms

Looking at historical storms is one of the best ways to understand the scale of a winter event. These storms weren’t just big; they dwarfed the monthly averages in a matter of hours.

The Great Blizzard of 1947

On December 26, 1947, a massive blizzard unexpectedly struck New York City. In just 24 hours, Central Park was buried under an astonishing 26.4 inches of snow. To put that into perspective, the city’s average snowfall for the entire month of December is only about 5 inches. This single storm delivered more than five times the typical monthly amount, paralyzing the city and becoming the benchmark for all future NYC snowstorms for decades.

The Mid-Atlantic “Snowmageddon” of 2009

In mid-December 2009, a powerful nor’easter hit the East Coast, an event that was later nicknamed “Snowmageddon.” Washington, D.C., recorded 16.4 inches of snow from this one storm. The city’s average snowfall for all of December is just 2.3 inches. This storm brought seven times the normal monthly snow in a single weekend, shutting down the nation’s capital. Philadelphia received over 23 inches, crushing its monthly average of 3 inches.

The Great Lakes Blizzard of December 2022

A historic blizzard, often referred to as Winter Storm Elliott, swept across North America right before Christmas in 2022. The storm was notable for its massive scale, high winds, and life-threatening cold. Buffalo, New York, was at the epicenter, receiving over 50 inches of snow from the event. This single storm nearly doubled the city’s already high average of 27 inches for December, creating impossible travel conditions and widespread power outages.

By comparing a current storm to these historic events and your local averages, you can get a much clearer picture of its significance.

Frequently Asked Questions

What is the difference between a snowstorm and a blizzard? A snowstorm is any storm that produces a significant amount of snow. For a storm to be officially classified as a blizzard by the National Weather Service, it must meet strict criteria: sustained winds or frequent gusts of 35 miles per hour or more, and considerable falling or blowing snow that reduces visibility to less than a quarter-mile. These conditions must last for at least three hours.

Where can I find the most reliable weather data for my area? The most reliable source for U.S. weather data is the National Weather Service (weather.gov). For historical climate data, including snowfall averages, the best resource is NOAA’s National Centers for Environmental Information (ncei.noaa.gov).

Does a very snowy December mean the rest of the winter will be extra snowy? Not necessarily. Weather patterns can change significantly from month to month. A snowy December can be influenced by short-term patterns like the position of the jet stream. While long-term patterns like El Niño or La Niña can influence the entire winter, a single snowy month doesn’t guarantee the trend will continue.