The Blizzard of December 8-9, 2009
It’s hard to believe that it has been 5 years since a large blizzard blasted Iowa on December 8-9, 2009. NWS Des Moines Meteorologists still reminisce and discuss this high-impact event as it produced some memories they won’t soon forget. For instance, it took a few forecasters at least 3 times longer to make it to work to cover their shift on that snowy Tuesday into Wednesday and a couple even stayed the night in the office on cots to wait out the storm! A recently hired intern had the task of measuring snowfall in the blizzard and when she went out at midnight Tuesday night on the 8th, she learned the hard way to always bring her security card with her in order to re-enter into the building as she locked herself out. Other forecasters remember being snowed-in and digging out 6 foot drifts from their driveways on Wednesday.
The storm began early Tuesday morning on December 8th when light to moderate snowfall extended across central to southern Iowa. The snow slowly spread over the rest of the state and intensified during the afternoon and evening hours and significantly affected the Des Moines rush hour Tuesday night. Strong northwest winds increased to 25 to 35 mph and gusted to over 50 mph at times by late Tuesday night and continued into early Wednesday morning. There were even a couple of reports of wind gusts to 60 mph overnight Tuesday into Wednesday. The strong winds and heavy snow produced large drifts throughout the state, with several reports over 6 feet! Visibility became reduced significantly as widespread whiteout conditions were observed from the overnight hours Tuesday into Wednesday before improving Wednesday afternoon. Travel became impossible or nearly impossible across much of Iowa due to the large drifts and widespread white-out conditions (See Figure 1).
The powerful storm dropped anywhere from 8 to 17 inches over much of Iowa with the highest swath oriented southwest to northeast across the state (See Figure 2). In fact, the statewide average storm total snowfall was 10.2 inches became the highest storm total since 1971 and the third-highest on record in Iowa. Some of the higher totals around the state included 15.5 inches in Des Moines, 16.0 inches in Atlantic and Belle Plaine, 16.2 inches in Corning and Osceola, and a whopping 17.0 inches in Knoxville. Des Moines recorded its this fourth-heaviest snow storm on record behind the December blizzard of 1888, the New Year’s storm of 1942, and the blizzard of March 2004.
The severity of the storm affected the surrounding states of Iowa as well. Blizzard warnings covered portions of eastern Nebraska, southern Minnesota, northern Missouri, the southern half of Wisconsin, and far northeast Kansas. All 99 counties in Iowa were under a blizzard warning Tuesday night into Wednesday (See Figures 3 and 4). A temperature gradient across Iowa late Tuesday night was about 25 degree difference from southeast to northwest Iowa (See Figure 5). By Wednesday afternoon, temperatures plummeted into the single digits to around 10 above, leading to wind chill values as low as -31F at Mason City on the 9th. The snow finally tapered off by Wednesday afternoon but the howling winds continued into Wednesday night. High pressure built into the region and brought clear skies on Thursday allowing the large swath of snow to be seen on visible satellite (See Figure 6). If residents of Iowa remember, this big blizzard was just the beginning of a very active winter with frequent snowfalls and persistent deep snow pack across the state.
Figure 5: Temperature difference across Iowa at 2 am Wednesday morning December 9, 2014. Temperatures in the lower 30s were found in southeast Iowa while the northwest part of the state dropped to 5 to 10 above. Image via IEM.