# Armistice Day Storm, 1940: a 55-degree Chicago morning became a Midwest blizzard Published November 11, 2026, 6:32 AM ET ยท Updated November 11, 2026, 9:03 AM ET By Ryan Hall, Y'all Written by our automated news desk from National Weather Service data. On Monday, Nov. 11, 1940, a mild morning in the 40s and 50s across Minnesota, Iowa, Wisconsin and Illinois turned into a blizzard by afternoon, with 26.6 inches of snow at Collegeville, Minnesota, and single digits by the next morning. Nothing like it is on the map today, Veterans Day 2026: only a Level 1 of 5 risk for isolated severe storms from Illinois to Tennessee. The first accumulating snow is likely Thursday in the higher terrain of the central Appalachians and interior Northeast. **What's new:** Rewrote with new details on the morning temperatures, the cold front timing and the record low pressures; removed the track map; updated today's outlook. ## Key points - **Where:** Minnesota, Iowa, Wisconsin, Illinois, the Dakotas and Lake Michigan. - **When:** Monday, Nov. 11, 1940. Warm at 7:30 AM, with a strong cold front arriving from late morning into early afternoon. - **What:** A rapidly deepening low set record-low pressures. Rain turned to sleet, then to driving snow, with 30 to 50 mph winds. - **What it means today:** The storm helped change how forecasts are made. This Veterans Day is calm by comparison, with the first accumulating snow likely Thursday in higher terrain of the central Appalachians and interior Northeast. ![Newsroom graphic (graphic by the Ryan Hall, Y'all newsroom)](https://public.yallsoft.app/rhy/blog/images/2026-11-11-news-newsroom-82786171-0-1147.png) On Monday, Nov. 11, 1940, a mild morning in the 40s and 50s across Minnesota, Iowa, Wisconsin and Illinois turned into a blizzard by afternoon, with 26.6 inches of snow at Collegeville, Minnesota. Winds of 30 to 50 mph piled drifts up to 20 feet high near Willmar, Minnesota, and temperatures were in the single digits by the next morning. Today, 86 years later, nothing like it is in the forecast. There is a Level 1 of 5 (Marginal Risk) for isolated severe storms from Illinois to Tennessee, and the first accumulating snow is likely Thursday in the higher terrain of the central Appalachians and interior Northeast. ## A warm morning and a forecast that called for flurries At 7:30 AM on Nov. 11, 1940, it was 55 degrees in Chicago and 54 in Davenport, Iowa. Across the Upper Midwest, morning temperatures sat in the 40s and 50s under blue skies. The forecast called for colder air and a few flurries. Duck hunters headed into the Mississippi River marshes in short sleeves, and the change caught them there. ## How the low got so strong A low-pressure system moved from Kansas City northeast through the Upper Mississippi Valley and into the Upper Great Lakes. It deepened fast along the way and set pressure records in three places. Charles City, Iowa, dropped to 28.92 inches, La Crosse, Wisconsin, to 28.72 inches, and Duluth, Minnesota, to 28.66 inches. Each was the lowest ever recorded at that spot up to that time. A strong cold front came through from late morning into early afternoon. Rain turned to sleet, then to driving snow, and the temperature dropped hard behind the front. By the next morning it was in the single digits. ## What the storm left behind Collegeville, Minnesota, picked up 26.6 inches of snow. Winds of 30 to 50 mph blew it into drifts as high as 20 feet near Willmar. The storm killed 154 people across the region, 49 of them in Minnesota and 59 in shipwrecks on Lake Michigan. How fast the change came, from shirt sleeves to a blizzard in hours, is why people still remember it. ## Why it changed forecasting The Weather Bureau took a hard lesson from that day. Forecasting moved from a single Chicago office to regional centers, so more eyes were watching more of the map. ## What today and this week look like Nothing close to 1940 is in the works. The Level 1 risk for isolated severe storms covers Illinois, Indiana, Kentucky and Tennessee today, the lowest rung on the scale. No flash flood risk is outlined, and no severe storms are expected Thursday or Friday. Colder air is the bigger story. A developing storm Thursday brings a Marginal risk of winter weather impacts to portions of the upper Great Lakes and the interior Northeast. The first accumulating snow is likely in the higher elevations of the central Appalachians and interior Northeast. On Friday, Nov. 13, the Marginal risk covers the upper Great Lakes, Northeast terrain and the central Appalachians. Out West, mountain snow is lined up for the Intermountain West and Rockies starting Saturday, Nov. 14. A stronger system arrives Monday and Tuesday. Confidence is high through Sunday and moderate after that. ## What to do - In the lower Ohio and Tennessee Valleys, keep an eye on the sky today. Check our [severe storm outlook](/severe) before afternoon plans. - Heading into the Appalachians or interior Northeast on Thursday or Friday? Check the [snow forecast](/snow) and our [winter storm outlook](/winter) first. - Hunters, anglers and hikers in higher terrain should carry extra layers and a way to stay dry. The 1940 duck hunters were caught by the rapid change. - Sign up for free [Y'all Alerts](/alerts) so a change in the forecast reaches you early. ## Bottom line On Armistice Day 1940, a mild morning gave almost no hint of the blizzard that followed, and the lesson stuck. Today is a low-end severe day in the Ohio and Tennessee Valleys, with the first accumulating snow in the central Appalachians and interior Northeast likely Thursday. ## The numbers ### Record low pressure readings, Nov. 11, 1940 | City | Lowest pressure | Note | | --- | --- | --- | | Charles City, Iowa | 28.92 inches | Lowest ever recorded there up to that time | | La Crosse, Wisconsin | 28.72 inches | Lowest ever recorded there up to that time | | Duluth, Minnesota | 28.66 inches | Lowest ever recorded there up to that time | Source: National Weather Service historical summary of the Armistice Day Storm Explained: [What makes a blizzard, and what a Blizzard Warning means](https://ryanhallyall.com/news/what-a-blizzard-warning-means) More on: [Midwest winter weather, November 2026](https://ryanhallyall.com/news/topic/midwest-winter-weather-november-2026) Places in this story: Chicago, IL; Collegeville, MN; Willmar, MN; Davenport, IA; Charles City, IA; La Crosse, WI; Duluth, MN ## Sources - [NWS La Crosse, 'Armistice Day Storm: November 11, 1940'](https://weather.gov/arx/nov111940), National Weather Service - [NWS Quad Cities, 'Armistice Day Blizzard of 1940 Remembered'](https://weather.gov/dvn/armistice_day_blizzard), National Weather Service - [NWS Chicago, 'Armistice Day Storm of 1940'](https://weather.gov/lot/1940Nov11_armisticeday), National Weather Service - NWS national headline on weather.gov (shown on the NWS Quad Cities page), National Weather Service --- Canonical: https://ryanhallyall.com/news/armistice-day-storm-86-years-ago-a-55-degree-morning-became-a-blizzard From Ryan Hall, Y'all (https://ryanhallyall.com). Always follow official warnings from the National Weather Service.