Swift and Lower Two Medicine dam breaks

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Map: USA
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Swift Dam
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United States

On June 8, 1964 , the Swift Dam on Birch Creek broke in Montana , USA, killing 19 and the Lower Two Medicine dam , causing 9 (or 30) deaths.

The storm

Since June 6th, several storms have hit the Rocky Mountains in western Montana and brought heavy rains with them. Record-breaking rainfall of 200 to 350 mm fell in 24 hours. The water of the Sun River , which flows into the Missouri River , even dammed up the Missouri on June 9 and 10, causing floods that had to relocate 3,000 people.

Swift Dam

Several irrigation dams broke on several tributaries of the Marias River . At 10:00 a.m. on June 8, the Swift Dam on Birch Creek in Pondera County failed after being flooded. The 47.9 m high Swift Dam ( 48 ° 9 ′ 45.8 ″  N , 112 ° 52 ′ 19.2 ″  W ) was 49 years old and had a storage space of 42.31 million m³. The valley of Birch Creek was devastated by a 6 m high tidal wave that destroyed all buildings, bridges and farms on its way. 19 people and also many horses and cattle drowned.

Lower Two Medicine Dam

On the same day at 3:30 p.m., the 11 m high Lower Two Medicine Dam ( 48 ° 30 ′ 6.1 ″  N , 113 ° 17 ′ 12.2 ″  W ) in Glacier County , also in northwestern Montana. This dam was 51 years old and contained 25.82 million m³. There were nine deaths in a Blackfoot - Indian Reservation . According to another report, 30 Blackfoot Indians died when the Lower Two Medicine Dam broke.

See also

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