Indiana’s winter climate features significant shifts in temperature and snowfall, often leading to severe weather events. While heavy snowstorms are a regular occurrence, the specific meteorological phenomenon known as a true blizzard is a rare event across the state. These powerful storms require a precise and sustained combination of factors to meet the official classification, meaning many memorable winter events do not qualify. This distinction, set by the National Weather Service (NWS), is what separates a major snowstorm from a genuine blizzard, providing a critical lens for examining the historical context of Indiana’s most extreme winter weather.
Defining the Criteria for a Blizzard
The National Weather Service maintains a strict definition for a storm to be officially categorized as a blizzard, which goes beyond simply measuring heavy snowfall. A storm must simultaneously meet three distinct criteria for a minimum period of three consecutive hours to receive the classification. The first condition is the presence of sustained winds or frequent gusts reaching 35 miles per hour or greater. This wind speed is sufficient to create whiteout conditions by lifting snow already on the ground, a phenomenon known as a ground blizzard.
The second and third criteria are directly related to visibility and the presence of snow. There must be considerable falling and/or blowing snow, which frequently reduces visibility to one-quarter of a mile or less. A storm that dumps a foot of snow but lacks the sustained high winds will only be classified as a winter storm, not a blizzard. This rigorous standard highlights why true blizzards are so infrequent in Indiana, as the wind and visibility thresholds are exceptionally difficult to maintain for a three-hour duration across a wide area.
The Most Recent Official Blizzard in Indiana
The last time an official blizzard classification was verified in Indiana occurred during the powerful December 2022 Winter Storm and Arctic Blast. This event, which struck just ahead of the Christmas holiday, saw blizzard conditions realized in the far northwestern part of the state. Specifically, the NWS confirmed that the counties of LaPorte and St. Joseph met the full criteria, with conditions lasting for an extended period.
The storm was triggered by a rapid drop in atmospheric pressure, creating a “bomb cyclone” over the Great Lakes region and pulling a frigid Arctic air mass southward. Although snowfall totals across much of Indiana were only a few inches, the intense winds were the defining factor in the northwest. Wind gusts routinely exceeded 50 miles per hour, creating dangerous whiteout conditions in open and rural areas of the two counties.
In LaPorte and St. Joseph counties, the combination of strong winds and blowing snow reduced visibility to below one-quarter mile for over 24 consecutive hours in some locations. This sustained duration far exceeded the three-hour minimum required for an official blizzard classification. The resulting conditions caused massive travel disruptions, forcing the closure of portions of major interstates like I-65 and I-94 in the region. The extreme cold that accompanied the event, with wind chills plummeting to as low as -40°F, made the conditions exceptionally dangerous.
Notable Severe Winter Events Not Classified as Blizzards
While the December 2022 event was the most recent official blizzard in a localized portion of the state, the Great Blizzard of 1978 remains the benchmark for Indiana’s winter weather history. The 1978 storm, which began on January 25, holds the distinction of being the only time a statewide Blizzard Warning was issued for Indiana. Winds gusted to 55 miles per hour, and visibility remained near zero for 25 hours, leading to widespread structural damage and a complete shutdown of the state.
Despite its lasting memory as a blizzard, the central Indiana portion of the December 2022 storm failed to meet the complete NWS criteria, even though it was highly impactful. The area experienced a rapid temperature drop and strong wind gusts up to 56 mph, which caused a flash freeze on wet roads and led to massive travel issues. Snowfall in central Indiana was limited to between one and three inches, and the duration of the reduced visibility did not meet the three-hour minimum threshold.
This difference illustrates the critical role of the visibility and duration criteria in the NWS definition. The extreme winds and cold of the 2022 storm were present across the entire state, but the necessary volume of falling or blowing snow to sustain a quarter-mile or less visibility for the required time only occurred in the northernmost, lake-adjacent counties.