Top 5 Two Day Snowstorms Series: Chicago

Winter 2019-2020 is off to a pretty strong start. Lots of people are saying we skipped fall and went right into winter. If you are located in the northern half of the country, that definitely feels true, but let’s gain some perspective and take a look at some of the bigger snow storms to hit across the United States in the past. We’re kicking off a series that looks at top five 2-day snowfall for some of our largest and snowiest cities. This week we look at the top 5 snow storms for Chicago.

Table 1 lists the top five snowfalls at O’Hare airport, over two days, since 1958. This table doesn’t match the top five biggest snowstorms for Chicago. Why? Because we stop the term at two days. Some of the larger snow storms to impact Chicago occurred over 3 days or parts of three days.

Top 5 Chicago Snowfalls Since 1958 Chart

The largest snowstorms in Chicago produce considerable snow but they aren’t the highest totals, as compared to other metropolitan areas of the United States. However, they still produce significant amounts of snow. The top five snowstorms produced a narrow, but high range, of 17.9” to 20.6” of snow. They also all fall in a narrow time frame of one month – January 2nd to February 2nd. That is very interesting and may be the result of a small sample size or it could be climatology. Compared to other cities in our review, this is a narrow time frame.

January 2, 1999 Snowstorm

This storm took a track that favors snow and heavy snow for Chicago. The track is common in our list of top 5 snowstorms for Chicago. Image 2 is a surface map from 6am Saturday, January 2, 1999. It shows an area of low pressure north of Memphis, Tennessee. The central pressure is less than 1004mb. South of that area of low pressure is another with a pressure of 1002mb in southern Arkansas. Chicago and the surrounding counties are reporting temperatures in the teens under moderate to light snow with a southeast wind. Snow would continue through the day.

Chicago 1/2/99 Snow Map

Image 3 is a surface map from 6am Sunday, January 3, 1999. It shows the area of low pressure has moved north and east into northern Lower Michigan and strengthened. The pressure has fallen to 993mb. Skies are cloudy to mostly cloudy to cloudy with snow showers in and around Chicago. Temperatures remain in the teens. By Sunday afternoon, snow showers began to end and arctic air moved in behind the storm for several days.

Chicago 1/3/99 Snow Map

This is a prime track for significant snow for Chicago. Here are the reasons why:

  1. The storm travels from the south. This results in a large transport of moisture from the Gulf of Mexico.
  2. The storm track remains east of Chicago. Warm air advection remains to the east and this favors an all snow event for Chicago, as the city remains on the cold side of the storm.
  3. The storm is strengthening as it moves from south to north. Those are three significant and repeatable factors in large Chicago snowstorms.

The National Weather Service out of Romeoville has a very good write up on the Blizzard of 1967 along with statistics on some of Chicago’s largest snowstorms. You can read about that here: