Rick Atterberry, EDEN Immediate Past Chair, writes about the weather.
Last week we talked about the definition of a blizzard and the difficulties inherent in forecasting winter storms. This past weekend provided another concrete example of both in the form of the Super Bowl Blizzard of 2015 here in Illinois and surrounding states.
National Weather Service forecasters started looking at the setup nearly a week out. But the computer models upon which they depend were all over the place early in the week of January 26th. A very complicated scenario was developing, but forecasters approached the storm with caution because of relatively low confidence in any one computer model through midweek.
By Thursday, January 29th, it was apparent that there would be fairly heavy snow across parts of Iowa, Illinois and Indiana. Initially, the thought was that the heaviest snow would be about 6 to 10 inches in an area north of Interstate 74 across the center of Illinois. However, each ensuing model run moved the heaviest precipitation farther north. Adding to the uncertainty was the fact that some of the area would see temperatures in the low to mid-30s during much of the event. How much precipitation would fall as snow and how much as rain? The forecasters were certain this would be an unusually long event.
Here at the University of Illinois in Urbana-Champaign we had freezing drizzle and sleet followed by a period of snow followed by rain then more wet snow and finally drier snow overnight Sunday. We ended up with about four inches of snow which quickly compacted to two inches during the rain and then added less than an inch as the event concluded.
The main snow event was located 100 to 130 miles north of us along the Interstate 80 and 88 corridors. Each forecast from Saturday into Sunday added to the possible snow totals in the Metropolitan Chicago region. By Sunday noon, the forecast called for 16 to 20 inches of snow in some spots and, indeed, that’s what happened. In 30 hours between late Saturday night and early Monday morning, the official measurement at O’Hare Airport was 19 inches of snow…the fifth highest single event total in the city’s recorded history. Thousands of flights were cancelled. Chicago public schools closed on Monday. Blizzard conditions…winds of 35 miles per hour or more and visibilities under ¼ mile…developed in the city and rural areas.
Here’s a time lapse video from Judy Hsu at WLS-TV. Note the clock on the fence.
When the area of heaviest snow moved north to the Chicago area, Lake Michigan came into play. When winds clocked around to the north-northeast, some snowfall amounts were enhanced by the lake effect.
“Heart attack snow”- Not only was the general snowfall in the region between 14 and 20-inches, the event began with heavy wet snow, the kind we call “heart attack snow” because of the physical demands of shoveling it. Sadly, in DuPage County in suburban Chicago, three men died of heart attacks associated with shoveling the snow. Cardiologists recognize the increased risk.
So, while it appears there were no fatalities from car accidents, falling tree limbs, structure fires, carbon monoxide poisoning or other threats often associated with cold and snow, heart attacks did claim lives. Those of us who are 55 and older or with a history of heart disease need to proceed with caution.