The Blizzard of January 25-26, 1978
Melissa Watson, Undergraduate Geographer/EIUWC Weather Analyst
January 27, 2012
The Blizzard of January 25-26, 1978 would make history as one of the most powerful winter storms in US history. This blizzard, also known as “The Great Blizzard” and the “Cleveland Bomb,” is distinctive because of the fast drop in barometric pressure in a 24-hour period. A blizzard is defined as storms that have sustained winds or frequent gusts above 35 miles per hour (mph) combined with considerable blowing or drifting snow reducing visibility to under a quarter mile for 3 or more hours. Knowing that, “The Great Blizzard” had high amounts of snow precipitation and wind gusts of 55 miles mph that brought wind chills down to -60 degrees, which is well within the definition of a blizzard. The National Weather Service (NWS) stated that the maximum snow amount for parts of Central and Southern Indiana were at 20 inches and up to 40 inches in the Northern part of Indiana.
This paper will discuss the major factors that caused the blizzard of 1978 to become such a significant winter storm and some of the statistics of this event. Surface and 500mb surface charts will be used in this synoptic analysis.
January 24, 1978
There were two troughs; the southern trough was located over northern Arizona while the northern trough was situated over northern Manitoba, as seen on the 500mb surface chart (figure 1). Both the northern and southern troughs exhibit a positive tilt with the axis running approximately east to west. This means that the troughs are “deepening” and will usually be “pushed” to the southeast.
Figure 1. 500mb chart for January 24, 1978.
January 25, 1978
According to the 500mb chart (figure 2) the two troughs have begun to migrate and strengthen within the last 24 hours. The new location for the northern trough is now positioned over northern Minnesota. Looking back to figure 1 and then comparing it to figure 2, we can see that the northern trough is now what is called a “closed low” in figure 2. This means that the isobars directly surrounding the low pressure system have now closed making a complete circle around the low and may cause the trough to move more slowly. The wind barbs associated with this trough indicate an increase in winds signifying stronger vorticity values. While this trough still exhibits a positive axis, running northeast to southwest, the tilt of this trough has become more negative. When the tilt and axis are negative, this means the trough is weakening.
Along with that the southern trough has also strengthened over the last 24 hours, as stated previously. The new location for the southern trough is now positioned over central Texas. This trough, like the northern trough, is gaining strength in positive vorticity values and the southern trough is becoming smaller in size.
According to the surface chart (figure 3), the position of the southern surface low is over northern Mississippi directly in the positive vorticity advection zone (PVA zone) of the southern trough. Because of the upper- level divergence at that location, the surface low will strengthen. The northern surface low is positioned in the northern portion of the PVA zone of the 500mb chart signifying a strengthening system.
The two high pressure cells together along with the Rocky ridge will manipulate the two surface lows and the upper level troughs to come together. This will cause the pressure to lower and produce the blizzard conditions on Jan 26 1978.
Figure 2. 500mb chart for January 25, 1978.
Figure 3. Surface chart for January 25, 1978.
January 26, 1978
Having said that, the 500mb chart (figure 4) shows the two troughs have now converged into one low pressure system that is over the Great Lakes area. Because the contours are so close together (or “tight”) during this time, it shows the maturity of this system. Taking a closer look at figure 4, we can tell that the maximum winds will be along the southeastern portion of this storm because the contours are so close together. According to the surface map (figure 5) the surface low is located over Detroit, Michigan just north of the encircled trough and is at its lowest pressure. Because there is a strong vorticity on the northern and southern side of the low, the surface fronts spiral around in an unusual manner. Due to that, warm, moist air is being pulled from the Atlantic Ocean and the Gulf of Mexico across the northern side of the low pressure system feeding the backside of the system with snow. This system will not begin to dissipate until the surface low moves out of the PVA zone and move further into the center of the trough.
Figure 4. 500mb chart for January 26, 1978.
Figure 5. Surface chart for January 26, 1978.
Statistics of “The Great Blizzard”
According to the NWS in Indiana on January 25, the day started out with 5 inches already on the ground. By 7 pm, only one inch had been added, but became heavier by 10 pm. Just before midnight the arctic air started frequent gusts about 35 mph which created blizzard conditions that would continue undiminished for the next 24 hours.
Along with that, half an hour after the arctic front hurtled through the Indianapolis International Airport, on January 26, the airport closed because of the whiteout conditions. The strongest winds were achieved around 3 am for this blizzard. Furthermore, the temperatures dropped to zero during the morning and wind chills would remain around 40 to 50 below zero for most the day. As stated previously, portions of southern and central Indiana received around 20 inches of snow while the northern part of Indiana received around 40 inches of snow for this entire blizzard event. Because of all that snow, the weight of the snow caused several warehouse and factory roofs to cave in. Near Muncie a roof of a school also buckled and man from Shelby County was found in a snow drift dead in between his house and his office. During the morning of January 26 the governor of Indiana declared a snow emergency for the entire state. The snow drifs reached 10 to 20 feet high, which made travel practically impossible. The afternoon of the 26, the Indiana State Police announced that all Indiana roads were closed.
The Blizzard of January 25-26, 1978 is considered to be one of the worst winter storms in the Midwest in the twentieth century. For many states that were affected by this storm, the conditions that this storm brought (such as snow and temperature) were to become records for the state.
The blizzard first started to form when the two separate troughs eventually converged into one low pressure system. Warm, moist air was pulled out of the Atlantic Ocean and the Gulf of Mexico by this system and carried across the northern side of the low and fueled the backside of the low pressure system causing snow to fall from the storm. With the heavy snow fall, and the high winds, this fit the definition of a blizzard perfectly.
References and Further Information
National Weather Service, www.weather.gov
Craig, Cameron (2001) "The Blizzard of 1978," Indiana State University