Twin Ports flood of 2012

After heavy rain several weeks ago, more rain overnight has caused flooding around the Twin Ports and up the North Shore of Lake Superior.

A summer storm system was able to tap into moisture from the Gulf of Mexico last night and managed to squeeze out 8 inches of rain in Duluth by Wednesday morning, with many reports of 5 to 7 inches in the area.

I grabbed two screenshots from MSNBC, which picked up the photos from the Duluth News Tribune.

As of Tuesday evening there were reports of storm sewers "exploding" in downtown Duluth, below the hill, from all the water pressure seeking for a place to escape. 

By Wednesday morning, sinkholes were reported, along with roads and bridges washed out. Several people had to be rescued after attempting to drive across flooded roads.

The Superior office of Wisconsin Public Radio interviewed an emergency management official from Douglas County who reported someone was driving on Highway 13, north of US-2 in Douglas County, at a high speed to get across the water. The culvert under the water was missing and had left a hole 15 feet wild and 12 feet deep across the road, filled with water. The driver thought it was just water but didn't make it across. The car was damaged but the driver was rescued. 

Radar estimated a long swath of heavy rain has fallen from Brainerd and Aitkin, through Duluth and Superior, out over Lake Superior as of noon on Wednesday. 

Because of the impressive wording, I did want to copy and paste the discussion from the NWS office in Duluth last night:

NUMEROUS REPORTS OF FLOODING AND WATER COVERED ROADS HAVE BEEN 
RECEIVED FROM ACROSS THE ENTIRE AREA..AND WE CANNOT EMPHASIZE 
STRONGLY ENOUGH THE HIGH END NATURE OF THE FLOODING THREAT 
OVERNIGHT. THIS IS ESPECIALLY TRUE IN THE DULUTH AREA AND ALONG THE 
NORTH SHORE OF LAKE SUPERIOR..WHERE FLOODING THREAT WILL BE ENHANCED 
BY 1000-1500 FOOT TERRAIN DROP AND FLOOD WATERS RUSHING DOWN THE 
HILL.  STORM SEWERS IN DULUTH HAVE BEEN REPORTED AS EXPLODING FROM 
EXCESS WATER PRESSURE AT THE BOTTOM OF THE HILL..ALONG WITH FLOODING 
IN THE TUNNELS ON INTERSTATE 35 IN DULUTH.  ADDITIONAL FLOODING IS 
ALSO AFFECTING ALL RIVERS AND STREAMS ALONG THE NORTH SHORE..AND ANY 
CAMPGROUNDS AND RIVER/ROAD INTERACTIONS ALONG THE NORTH SHORE COULD 
BECOME POTENTIAL DEATH TRAPS OVERNIGHT WHEN THE FLOOD THREAT IS 
EXACERBATED BY DARKNESS AND LACK OF VISIBILITY.

That's the first I've seen the term 'death trap' used by the National Weather Service. In an earlier discussion yesterday, the meteorologists described how the cold air above Lake Superior is helping to set up the areas of heavy rain near the Lake:

HIGHLY UNSTABLE AIR IS UNDER-RUNNING A VERY STRONG MID-LEVEL HOT
TEMPERATURE CAP. THE NORTHERN EDGE OF THAT CAP RUNS ALONG A BRD-
DLH LINE THEN ALONG THE SOUTH SHORE OF LAKE SUPERIOR. RAIN IS
DIFFICULT TO UNLIKELY SOUTH OF THAT CAP...EVEN WITH DEW POINTS
ABOVE 20C. AS THE HOT HUMID AIR FLOWS NORTHWARD FROM UNDER THE
CAP...IT IS FORCED UP OVER A SHALLOW AND VERY DENSE MARITIME AIR
MASS...WITH STRONG AND BUILDING HIGH PRESSURE OVER CENTRAL LAKE
SUPERIOR. THIS UNDERRUNNING...THEN STRONG LOW LEVEL FORCING...
ALONG WITH OUR LOCATION IN THE RIGHT-ENTRANCE ZONE OF A 130 KT
HIGH-LEVEL JET...IMPLYING VERY STRONG UPWARD MOTION...WILL
CONTINUE TO RESULT IN VIOLENT AND INTENSE...POSSIBLY TORNADIC
THUNDERSTORMS. WITH PRECIPITABLE WATER OF 2 INCHES OR MORE AND THE
AFORE-MENTIONED DYNAMICS...THE THUNDERSTORMS WILL ALSO PRODUCE
FLOOD-PRODUCING DELUGES WITH VERY LARGE BASIN AVERAGE RAINFALLS.

With plenty of warning already yesterday afternoon, the intense rain shouldn't have been a surprise.

A blogger on a different website dug up some history from a similar flood in 1972:

Three flash floods in 1972 occurred in Duluth, Minnesota. The largest flash flood hit the area on September 20 and caused two deaths and $1 million in damages. The largest recorded storm in Minnesota history occurred on July 21, 1972, in central Minnesota. A detailed map of this storm was prepared by NWS with data from 245 reporting stations including 215 reports from Operation Rain Gauge. These reports make this the most thoroughly documented heavy rainstorm in Minnesota's history. The storm caused the greatest monetary losses ever experienced in the state for a flash flood. Total damages are estimated at 20 million dollers. Of this total, 5.9 million dollars were damages to the road system, and 3.1 million dollars of this involved damages to the federal-aid system. The events that occurred at Clarissa, Minnesota, a typical small-town community with a population of 599, during this storm are discussed. Also included in this report is a discussion of the occurrences during three large thunderstorms which struck the City of Duluth, a metropolitan area of 100,000 people, during August and September of 1972. The purpose of this report was to illustrate the dilemma faced by the highway engineer, whose task is to properly assess the public benefit versus the high economic cost factors involved in designing drainage structures for passage of runoff from large storms without adequate research information on the probable frequency, magnitude, duration, and location of these storms.

The USGS gauge at the Nemadji River in Superior has already risen above flood stage and continues to rise. As more rain falls and the surge of water moves down the river, more river flooding is expected. 

All rivers and streams around the Twin Ports are currently flooding and will take time to crest yet.

With culverts and bridges missing, law enforcement in the affected area are encouraging people to stay home. Fire, ambulance, and police are having difficulty reaching people in need of rescue and will have problems responding to emergencies.

And finally, some bullet points:

* 02:26 -- numerous roads are washed out or flooded within Duluth. This includes several sinholes and collapsed roads. Reports of high water rescues and evacuations in progress across the city.

* 08:00 -- Jay Cooke State Park was evacuated due to flooding

* 08:00 -- the reservoir at the city of Thomson overflowed, and Carlton County emergency management has ordered evacuation of the city of Thomson

* 08:10 -- communication in Lake County is out. There is no internet, cell phone, or land line at the Sheriff's Department

* 08:45 -- report of 8.38 HEAVY RAIN from Morley Heights neighborhood of Duluth

 * 09:41 -- Spafford camping area evacuated... next to the St Louis River

* 11:35 -- in Midway Township, the Midway River is flooding onto Midway Road...and the road is being washed out at this time

* Interstate 35 flooded and closed in several sections, including the city's downtown tunnels

* A polar bear and seal escaped from Duluth Zoo during the flooding, both recovered safely

* All but one of the zoo's barnyard animals died, including the zoo's donkey, goats and sheep