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Twin Cities average April snowfall has tripled in the past decade

Three straight snowy Aprils have changed Twin Cities weather records

Snow ruler
Snow drift in April 2018 blizzard.
Paul Huttner | MPR News 2018

Three straight snowy Aprils in the Twin Cities are changing our weather records. Average April snowfall for the Twin Cities has tripled during the past decade.

The long-term average April snowfall for the Twin Cities is 2.4 inches in the most recent set of 30-year climate normals for the Minneapolis-St. Paul International Airport.

But over the last decade, the Twin Cities average April snowfall has soared to 7.1 inches. That’s about three times our long-term April snowfall average.

A person surfs behind a boat in the snow.
A person surfs behind a boat during a snowstorm on Lake Minnetonka on Sunday.
Evan Frost | MPR News

Snowy April decade

The past decade has been very snowy in the Twin Cities overall. And the past three years stand out as s snowy cluster in the data.

Monthly snowfall for the past 10 years at MSP Airport
Monthly snowfall for the past 10 years at the MSP Airport.
Minnesota DNR Climate Working Group

In fact, three of the top 10 snowiest April have occurred since 2011.

Top 10 April snowiest Aprils in the Twin Cities
Top 10 April snowiest Aprils in the Twin Cities
Minnesota DNR Climate Working Group

The Twin Cities has a robust snowfall database going back to 1884.

I made this simple chart to show how the average April snowfall in the Twin Cities has increased in the past three decades.

Average April snowfall for the past 3 decades
Average April snowfall for the past 3 decades
NOAA data

30-year averages

When meteorologists talk about the “average” high or low temperatures, we are using 30-year averages. This longer time period establishes historical context on weather normals and extremes.

Here’s more from NOAA on the use of 30-year climate normals.

NOAA's computation of Climate Normals is in accordance with the recommendation of the World Meteorological Organization (WMO), of which the United States is a member. While the WMO mandates each member nation to compute 30-year averages of meteorological quantities at least every 30 years (1931–1960, 1961–1990, 1991–2020, etc.), the WMO recommends a decadal update, in part to incorporate newer weather stations.

Meteorologists and climatologists regularly use Climate Normals for placing recent climate conditions into a historical context. NOAA's Climate Normals are commonly seen on local weather news segments for comparisons with the day's weather conditions. In addition to weather and climate comparisons, Climate Normals are utilized in seemingly countless applications across a variety of sectors. These include regulation of power companies, energy load forecasting, crop selection and planting times, construction planning, building design, and many others.

New 30-year averages due out next year

The next set of updated 30-year averages comes out in 2021.

Based on my preliminary scan of snowfall data including this April, it looks like the new 30-year (1991-2020) Twin Cities average annual April snowfall will move from 2.4 inches to about 3.7 inches.

That’s a 54 percent increase in the 30-year average April snowfall in the Twin Cities. April is still the sixth-snowiest month on average.

It may be a decadal blip or a longer-term trend. But our April snowfall average in the Twin Cities has basically tripled from 2.4 inches to 7.1 inches during the past decade.