The Great Duluth, Minnesota Flood of 2012

The Great Duluth Flood of June 19-20, 2012 Paul Huttner – Chief Meteorologist Minnesota Public Radio

Abstract:

On the afternoon of Tuesday June 19th, 2012 a potent warm front stalled just south of Duluth Minnesota. The front focused continuous lift for developing thunderstorms over east central Minnesota. The storms tracked northeast into Duluth, the North Shore of Lake Superior and northwest Wisconsin.

Throughout the night, multiple bands of heavy “training” thunderstorms dump torrential rainfall on Duluth and the North Shore. By early Wednesday morning the 7.25” rainfall at the Duluth NWS breaks the 2-day rainfall record in Duluth and nearly doubles previous record flood totals of 1972. A storm total rainfall of 10.10” is recorded by an off duty NWS employee 3 miles NE of Duluth.

Intense rainfall rates of 1” to 2” per hour overwhelm storm drainage capacity in Duluth. Duluth's 43 “urban streams” rapidly swell with raging floodwaters, and cascade beyond their banks tearing up dozens of streets and invading hundreds of homes. Multiple areas of swift water runoff cascade downhill through a vulnerable city that sits on a steep rocky hillside perched above Lake Superior.

Numerous motorists encountered floodwaters and some vehicles were swept into sinkholes 15 feet deep. An 8-year-old boy is swept into a culvert while playing in the flood waters in Proctor. He is swept through the culvert for 6 or 7 blocks, but besides some scrapes, emerges unharmed. Miraculously no one is seriously injured or killed in the flood.

A raging Kingsbury Creek floods the Lake Superior Zoo, drowning over a dozen animals. Two seals are swept from their enclosures, but returned safely after being found on a local street. The polar bear escapes its exhibit, but is safely returned after being tranquilized by a dart.

Numerous roads were washed out from the deluge from Carlton County through the Duluth metro area and into Douglas County and Bayfield County in Wisconsin.

A state of emergency was declared in Duluth, Hermantown, Cloquet, Barnum, Moose Lake and Superior, WI.

By the time it ends, a 500-year flood has caused over $100 million damage to Duluth's infrastructure. What synoptic conditions caused the flood? Why is Duluth especially vulnerable to intense rainfall events? What actions are underway to rebuild Duluth for the observed increase in excessive rainfall events?