S. Ahead of it, a surface low formed to the west of Iowa along an approaching cold front.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS DMX wrote it up.
A strong upper level low pressure area moved into the central U.S. Ahead of it, a surface low formed to the west of Iowa along an approaching cold front. Southerly winds pushed moisture north with precipitable water values increasing to 1.25 to 1.5 inches, near the 99th percentile for the time of year. Surface dewpoints surged into the mid 60s with elevated CAPE values of 1000 J/kg present. Weak shear was in place with 20 to 30 kts of effective shear. The freezing level was around 11,500 feet with CAPE in the -10 to -30 C layer of the atmosphere between 300 and 400 J/kg. This was enough to produce some penny size hail in Cass County south of Atlantic. Although there was about 1000 J/kg of downdraft CAPE present, it was not able to be realized as the low levels of the atmosphere had cooled before the storms moved into the area. Gusty winds of 30 to 40 MPH occurred however. Several locations reported 3 to 5 inches of rain from central into southeast Iowa. The rain fell in a 24 hour period for the most part. A few totals noted went from Friday evening into Sunday morning, however nearly all of the accumulating rainfall occurred Saturday into Saturday night.
The Des Moines radar (KDMX), 54 km away, was scanning. The volume nearest the first event began at 11:57 UTC.
9 heavy rain, 1 hail. Local standard time, as filed.
Near I-80 and Highway 14 interchange. Storm total since Friday evening was 4.25 inches.
Twenty four hour rainfall from Neil Smith Wildlife Refuge. Total was 3.13 inches.
Twenty four hour total from APRS weather network. Total was 3.42 inches.
Coop reported 3.40 inches of rain. Was 48 hour total, but very little fell before Saturday morning.
Twenty four hour total of 5.10 inches.
Twenty four hour total of 3.06 inches.
Twenty four hour total of 3.02 inches.
Twenty four hour total of 3.29 inches.
Total rainfall of 4.90 inches in 36 hours, most of which was in past 24 hours.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2012Every state in 2012This day in weather historyWarnings in Iowa, October 2012
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 407942, 407943, 407944, 407945, 407946, 407947, 407948, 407949, 407950, 407899.