Spring flooding, and a look back at some historic Montana floods

Mother Nature is, as usual, calling the shots this spring.

In the Mississippi River basin, Ol’ Man River is at its highest levels since the record floods of 1927. On the other hand, Texas and Oklahoma are in a severe drought and they’d like to have some of that water. Joplin, Missouri is cleaning-up following a devastating tornado last week, a storm that killed 116 people (at last count) and injured hundreds more.

Here in Montana people in river valleys are looking nervously at rising waters and wondering how high waters will rise. We have prime conditions for severe flooding this year, with a well above average snowpack and a cold spring that has kept that snowpack in place.

Last week there was flooding in eastern Montana, closing I-90 at Hardin, due to heavy rains that sent creeks over their banks., converging near the Little Bighorn Battlefield.

In western Montana, the big question is whether we’ll have either a heat wave or heavy rains to send all that snowpack down the mountains in one big surge of water.

Let’s take a look back at some historic Montana floods.

On June 19, 1938, a flash flood on Custer Creek near Terry, Montana, washed out a railroad bridge across the creek. When the Northern Pacific Olympic Special came through in the middle of the night, it crashed into the waters. 46 people were killed and many more were injured.

In 1997, Livingston experienced what was considered a 100-year flood in a scenario similar to this year. The mountains in the area had a snowpack of 200 percent of normal. In mid-May there was a heat wave with temps in the 80s, and that was followed by heavy rain.

Northwest Montana, on both sides of the Continental Divide, experienced what is considered Montana’s flood of the 20th Century in June 1964. Rainstorms on June 8 - 10 dumped as much as 14 inches of rain along the Divide in a 36 hour period, and streams that were already running high with snowmelt surged with water. Gibson Dam, on the upper Sun River, overflowed and floodwaters took out homes, roads and bridges all the way to Great Falls.

Farther north along the Divide, flooding on the Teton and Marias river systems destroyed an irrigation dam near Dupuyer, and caused massive damage on Blackfeet reservation communities of Heart Butte and Browning. In Glacier National Park, roads washed out, isolating Many Glacier hotel from Babb.

West of the Divide, the Middle Fork of the Flathead River went wild. The Flathead River at Columbia Falls crested at over 12 feet above flood stage. Areas up to a mile from the river were under four feet of water. Some 20,000 acres and several hundred homes along the Flathead River were flooded.

In a 2007 article in the Daily InterLake of Kalispell, reporter Heidi Gaiser noted one area that was hard hit in 1964, the community of Evergreen, along U.S. 2 northeast of Kalispell. Evergreen now has extensive commercial development in areas that went under water in 1964. As for possibilities of future flooding, Flathead County planner Tracy Sears-Tull said in that report, “It’s not a matter of if, but when it will happen.”

In all, the 1964 floods caused 30 deaths and inundated 20 percent of Montana’s surface area, which is a lot of real estate.

Flooding is, of course, a natural event. Floods cause problems when we humans encroach onto flood plains and build structures. Catastrophic flooding happens when dams fail, with the failure of the Teton River Dam in southeastern Idaho in 1976 as a classic example of dam failure, with consequent loss of life and property.

There are benefits to flooding, in that the waters enrich the soil over the floodplain, adding nutrients and organic matter, plus recharging aquifers. We can look at ancient Egypt where an entire civilization grew up and flourished, totally dependent on the benefits of the annual flooding of the Nile River.

Just the same, I’ll be looking forward to a month from now when waters recede and trout are taking dry flies.