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They say that in Fargo/Moorhead, we’ll probably get a 38-foot flood this year. By “they” I mean the National Weather Service (NWS) and their Advanced Hydrologic Prediction Service. In historical terms, 18 feet is minor flooding, above 25 feet is moderate flooding, and anything above 30 feet is major flooding.

If it’s 38 feet, it would be the fifth worst flood in Fargo/Moorhead history. The worst floods in recorded history (going back about 120 years) were these:

2009 (40.84 feet)
1997 (39.72)
1897 (39.10)
2011 (38.81)
*2013 (*if it’s 38 feet)
1969 (37.34)
2006 (37.13)
2010 (36.99)
Note that four of the seven worst floods have occurred in the last seven years. If you add in 1997, five of the seven worst floods have been in the last 16 years.

I thought I’d combine some weather, geology, history (going back 9000 years!), with a bit of politics and current events. I will probably tell you more than you want to know about the 2013 Red River Flood. Which has not yet happened. It will probably start in a week or two.

More details below the delicious Pearson’s Nut Goodie.

Let’s begin with the NWS graph that predicts how big the flood will be this year (here’s the link: Red River at Fargo, ND and here’s the graph:

This is a prediction from about three weeks ago (3/25) and it’s based on measurements of water content in snow and weather predictions and various other scientific measurements. Ignore the blue line, which shows historical data. Look at the black line at the top. The average prediction for 2013 is 38 feet – meaning there’s a 50% chance we’ll have more than 38 feet of flood and 50% chance of less than 38. But there’s only a five percent chance of less than 34 feet. And there’s a five percent chance of more than 40 feet. So the river will most likely crest at somewhere around 34-40 feet at some point this spring.

Next question. Where is the river today? It’s about 15 or 16 feet. It’s not even at minor flooding stage yet. I looked at the river a couple days ago. It’s pretty sedate. Here’s a graph from the NWS as of April 9 (click the link here for current conditions: Red River of the North at Fargo):

The river is not flooding today or tomorrow. But I guarantee it will flood in the next week or three.

Fargo versus Moorhead

Here’s something I will mention: I grew up in and currently live in Moorhead, MN, which is why I call it the Fargo/Moorhead area. People in Fargo, ND, tend to call it just the Fargo area. Fargo is the largest city in ND (107,000 people more or less). Moorhead (across the river in MN) has about 38,000. West Fargo (Fargo’s biggest suburb) has about 27,000 people. Dilworth (Moorhead’s biggest suburb) has about 4,000). There are about 175,000 people in the metropolitan area. The Red River, which divides MN and ND, also is a divide between Democrats and Republicans, Midwestern and Western attitudes, pro-gun control and anti-gun control, pro-choice and anti-choice, LGBT rights and LGBT discrimination, and so on. Crossing the river, you leave a blue state and enter a red state. We’re more progressive on this side of the river.

The Drainage Basin

The Red River of the North officially starts in Wahpeton ND/Breckenridge MN where the Bois de Sioux River and the Otter Tail River come together.

Here’s a map of the Red River drainage basin (Note: The river flows north to Winnipeg, Canada, and then to Hudson Bay and the Arctic Ocean):

The river floods fairly often. Here’s a graph from Anne Jefferson’s 2011 blog post Why does the Red River of the North have so many floods? (well worth reading if you want to know about Red River flooding). Jefferson is a professor of geology and hydrology at Kent State. Here’s the historical record of floods in Grand Forks, ND:

So why does the Red River flood so much?

Reason 1: The land is very very flat

Look at that map of North Dakota. From the South Dakota border to the Canadian border, the slope of the land drops, on average, 1 foot over 5000 feet. About one foot per mile. It’s nearly flat. I’ll explain why below.

To visualize a slope of 1 unit per 5000, imagine a table that’s six feet long. One end is approximately 1/100th of an inch lower than the other end. Throw some snow on the table and apply some heat. The melted snow-water will spread out and pool before it eventually drains.

There are parts of the Red River where the flood plain is 50 miles on either side of the river.

Here’s a picture taken from an airplane to show you how flat it is:

That squiggly dark line is the Red River, which meanders back and forth because the land is so utterly flat. On the horizon you can see the curvature of the earth. The dark splotches are mostly farms, surrounded by trees that were planted to break the wind.

You’re looking at a glacial lake bed

This was once the bottom of a lake created by a melted glacier. Short version: The last ice age (the Wisconsin glaciation) lasted from about 85,000 to 10,000 years ago. When it ended, the ice melted and became a huge lake (known as Lake Agassiz).  Silt, dust, plant matter, dead fish, and various other stuff built up on the bottom of the lake over a few thousand years. When the lake finally drained (into the Arctic Ocean), it left behind a flat, fertile plain. This happened about 8000 or 9000 years ago.

Reason 2: There’s no valley to speak of

It took the Colorado River six million years to carve out the Grand Canyon. Parts of the Mississippi have been around for hundreds of thousands of years. Those rivers have well-defined valleys that were slowly cut into the land. The Red River is only about 9,000 years old. Geologically speaking, it’s just a baby river. And the land is flat. When it overflows, water goes everywhere. For miles.

Reason 3: The river flows north

Unlike most other rivers in the U.S., the Red River flows north. I think it's the only American river that flows into the Arctic Ocean.

Sometimes, if snow melts in the southern regions, and enters the river and flows north, but the weather is still cold up north in Grand Forks or Winnipeg, where the river is still frozen, the water will encounter ice dams. It will spread out and flood.

Reason 4: It’s all about melting snow

If the snow melts quickly (because of warm temperatures or because of rain falling on snow) or if the ground is still frozen hard (acting like pavement), all that water will rush into the river and it will turn into a flood. If the previous winter had a lot of snow, there’s a lot of water stored there.  If the previous winter had an average snow, but spring is suddenly warm or rainy, there will be a lot of water rushing into the river.

Here’s a fascinating and well-written link by Allen Voelker: ANATOMY OF A RED RIVER SPRING FLOOD, and here’s two excerpts about the non-flood of 1994:

The winter of 1993-1994 established a previous record snowfall at Fargo with 89.1 inches. With a record snowfall, one could certainly understand concerns about a possible significant flood that spring.
But there wasn’t a major flood….
The key to the spring flood that year was an ideal snowmelt scenario. Daytime high temperatures during the month of March and into April were greater than 32 degrees on all but 5 days which allowed a gradual snow melt. During this period, daytime highs generally ranged from 35 to 45 degrees with five days at or greater than 50 degrees. Also important was that nighttime lows fell below 32 degrees on all but five days during March. This cooling allowed snow to freeze at night slowing down melting and runoff which occurred during the day. As a result of the ideal melt, the Red River crested in Fargo on April 3rd at a stage of 26.70 ft.
27 feet is nothing. No big deal. A record snowfall that year, but the weather acted like a valve. Water entered the river during the day, but then it froze up at night.

The opposite of a flash flood

I’ve lived in the states of North Carolina and Washington, where there are mountains and occasional flash floods. If you live near a river fed by a mountain and if there’s a big rain, the water will rush downhill. You might have only an hour or two to get out of the way.

The Red River floods are slow. The water rises a little bit, slowly and relentlessly, day after day after day. You have lots of time to pile up sandbags and get ready.

Mitigation: Story 1

The 1997 flood hit Grand Forks, ND, hard. It’s the second largest city in North Dakota, about 75 miles north of Fargo. In 1997, the downtown area of Grand Forks flooded. Then a building caught fire and the firefighters couldn’t get to the building to put out the fire because it was surrounded by water. Here’s what the fire looked like:

Here’s the aftermath:

After that disaster, Grand Forks built up their dikes and created diversionary wetlands that would help prevent it from happening in the future. Winnipeg, Manitoba, has also done a good job of preparing for floods.

Mitigation: Story 2

Both Fargo and Moorhead have been buying the houses of people most at risk of being flooded (I think they paid home owners roughly 110% of market value) and building dikes and levees and generally trying to minimize the risk of flooding. There’s a map I found online that shows that I’m in the 500-year flood plain, just on the edge of the 100-year flood plain.  (There’s a 1% chance of a 100 year flood and 0.2% chance of a 500 year flood.)

Plus, volunteers have been filling up sandbags this week to prepare for the flood. Fargo got a bunch of middle school kids to fill and stack sandbags. Here’s a story from the local news: Students are set to help fill sandbags in Fargo. They reached the goal of 1 million sandbags on Wednesday or Thursday (a seven-year-old girl got a prize for filling the one-millionth sandbag). Volunteers got free pizza and free bus rides to the sandbag center.

Speaking of sandbags, here’s a very cool link, created by a graphic designer (in 2009) to help you visualize the volume and the weight of sandbags (juxtaposed with a normal person, city buses, elephants, and the Empire State Building): That’s a lot of sand..

One more thing


The flood of 2009 was what got me to join Daily Kos. I had been following DKos during the 2008 election but wasn’t motivated enough to sign up and post comments. I was happy just to read the articles. In 2009, however, when the Red River started to flood, people were writing about it here and I decided I had to join in and explain what I knew. And now I’m coming close to writing my 150th diary and my 5000th comment.

The flood of 2013 hasn’t started yet (the river is slightly above 15 feet, the last time I checked). But it’s coming. Hope you learned something from this essay about the Red River.

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