2011 Musselshell River flood
Encyclopedia
The 2011 flooding on the Musselshell River
in Montana
began about May 21, affecting large parts of central Montana. At Mosby, Montana
, the river crested at 16 feet (4.9 m) on Monday, May 23. The flood level at Mosby is 8 feet (2.4 m) and the record crest at that point along the Musselshell is 17.7 feet (5.4 m), set in 1993. The flooding was caused by up to 8 inches (203.2 mm) of rain combined with snowmelt.
On May 24 at Shawmut, near Harlowton
, a record pace was set, with a flow rate of 3670 cuft/s. The average flow is 183 cuft/s at that spot for May 24. The prior record at Shawmut was set in 2005 with a rate of 802 cuft/s. Several roads in the Musselshell watershed were already closed by this date.
The town of Roundup
suffered the most damage of any community along the Musselshell. Potable water, food, and medicine were major concerns. Flood waters along the Musselshell near Roundup were as much as 6 feet (1.8 m) deep, cresting over the weekend. Flooding near Roundup was at least 2 foot (0.6096 m) above record flood level and forced the evacuation of dozens of homes. On Thursday, May 26 the flooding inundated portions of Roundup, At Highway 87 the floodwaters were flowing at over 3670 cuft/s, more than 10 times the normal rate. On May 26 the Musselshell crested near Roundup at 14.16 feet (4.3 m). Its flood stage there is 10 feet (3 m). The previous record for that location was set in 1975 at 12.89 feet (3.9 m). In Petroleum County alone damage costs were estimated at USD$1.5 million.
By June 23, the Musselshell had receded back below its banks, FEMA
had assessed damage to public lands and was back in Roundup to assess damage to private lands and properties.
Flooding on the unconnected Yellowstone River
to the south prompted the closing of a 20 miles (32.2 km)portion of Interstate 90
from Livingston
to Springdale. Floodwaters from the tributary Pryor creek led to closing of Pompeys Pillar National Monument
. The Little Bighorn River
and related tributaries flooded the area around Crow Agency and shut down Interstate 90 from Hardin
to the Wyoming line for several days. Montana counties that were affected by the state-wide flooding in Spring 2011 include: Big Horn
, Carbon
, Garfield
, Granite
, Jefferson
, Judith Basin
, Missoula
, Musselshell, Petroleum, Sanders
, Wheatland
, and Yellowstone
. A state of emergency was declared in 51 Montana counties, cities, and Indian reservations. Flood waters from the Musselshell, Yellowstone, and several other Montana rivers flow into the Missouri River
and Mississippi River
, exacerbating the 2011 flooding in states such as North Dakota
and South Dakota
.
Musselshell River
The Musselshell River is a tributary of the Missouri River, long from its origins at the confluence of its North and South Forks near Martinsdale, Montana to its mouth on the Missouri River. It is located east of the Continental divide entirely within Montana in the United States...
in Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
began about May 21, affecting large parts of central Montana. At Mosby, Montana
Mosby, Montana
Mosby is an unincorporated community in southwestern Garfield County, Montana, United States. It lies along Highway 200 southwest of the town of Jordan, the county seat of Garfield County. Its elevation is 2,513 feet...
, the river crested at 16 feet (4.9 m) on Monday, May 23. The flood level at Mosby is 8 feet (2.4 m) and the record crest at that point along the Musselshell is 17.7 feet (5.4 m), set in 1993. The flooding was caused by up to 8 inches (203.2 mm) of rain combined with snowmelt.
On May 24 at Shawmut, near Harlowton
Harlowton, Montana
Harlowton is a city in and the county seat of Wheatland County, Montana, United States. The population was 1,062 at the 2000 census. The city was once the eastern terminus of electric operations of the Milwaukee Road railroad's "Pacific Extension" route, which went all the way to Avery, Idaho. ...
, a record pace was set, with a flow rate of 3670 cuft/s. The average flow is 183 cuft/s at that spot for May 24. The prior record at Shawmut was set in 2005 with a rate of 802 cuft/s. Several roads in the Musselshell watershed were already closed by this date.
The town of Roundup
Roundup, Montana
Roundup is a city in and the county seat of Musselshell County, Montana, United States. The population was 1,788 during the 2010 census.-Geography:...
suffered the most damage of any community along the Musselshell. Potable water, food, and medicine were major concerns. Flood waters along the Musselshell near Roundup were as much as 6 feet (1.8 m) deep, cresting over the weekend. Flooding near Roundup was at least 2 foot (0.6096 m) above record flood level and forced the evacuation of dozens of homes. On Thursday, May 26 the flooding inundated portions of Roundup, At Highway 87 the floodwaters were flowing at over 3670 cuft/s, more than 10 times the normal rate. On May 26 the Musselshell crested near Roundup at 14.16 feet (4.3 m). Its flood stage there is 10 feet (3 m). The previous record for that location was set in 1975 at 12.89 feet (3.9 m). In Petroleum County alone damage costs were estimated at USD$1.5 million.
By June 23, the Musselshell had receded back below its banks, FEMA
Federal Emergency Management Agency
The Federal Emergency Management Agency is an agency of the United States Department of Homeland Security, initially created by Presidential Reorganization Plan No. 1 of 1978 and implemented by two Executive Orders...
had assessed damage to public lands and was back in Roundup to assess damage to private lands and properties.
Flooding on the unconnected Yellowstone River
Yellowstone River
The Yellowstone River is a tributary of the Missouri River, approximately long, in the western United States. Considered the principal tributary of the upper Missouri, the river and its tributaries drain a wide area stretching from the Rocky Mountains in the vicinity of the Yellowstone National...
to the south prompted the closing of a 20 miles (32.2 km)portion of Interstate 90
Interstate 90
Interstate 90 is the longest Interstate Highway in the United States at . It is the northernmost coast-to-coast interstate, and parallels US 20 for the most part. Its western terminus is in Seattle, at Edgar Martinez Drive S. near Safeco Field and CenturyLink Field, and its eastern terminus is in...
from Livingston
Livingston, Montana
-Geography:Livingston is located at , at an altitude of 4.501 feet .According to the United States Census Bureau, the city has a total area of , of which, of it is land and 0.38% is waters.-Climate:-Demographics:...
to Springdale. Floodwaters from the tributary Pryor creek led to closing of Pompeys Pillar National Monument
Pompeys Pillar National Monument
Pompeys Pillar National Monument is a rock formation located in south central Montana, United States. Designated a National Monument on January 17, 2001, and managed by the U.S. Bureau of Land Management, it consists of only , making it one of the smallest National Monuments in the U.S...
. The Little Bighorn River
Little Bighorn River
The Little Bighorn River is a tributary of the Bighorn River in the United States in the states of Wyoming and Montana. The Battle of the Little Bighorn was fought on its banks in 1876, as well as the Battle of Crow Agency in 1887....
and related tributaries flooded the area around Crow Agency and shut down Interstate 90 from Hardin
Hardin, Montana
Hardin is a city in and the county seat of Big Horn County, Montana, United States. The population was 3,384 at the 2000 census.-Geography:Hardin is located at ....
to the Wyoming line for several days. Montana counties that were affected by the state-wide flooding in Spring 2011 include: Big Horn
Big Horn County, Montana
- National protected areas :* Bighorn Canyon National Recreation Area * Little Bighorn Battlefield National Monument- Economy :Coal Mining and Agriculture both play major roles in Big Horn County’s economy...
, Carbon
Carbon County, Montana
-National protected areas:* Bighorn Canyon National Recreation Area * Custer National Forest * Gallatin National Forest -Economy:During the early history of Carbon County, coal mining was the predominant industry...
, Garfield
Garfield County, Montana
-Politics:Garfield County is a solidly Republican county. It might be the most Republican county in Montana and one of the most Republican in the nation....
, Granite
Granite County, Montana
-National protected areas:*Deerlodge National Forest *Lolo National Forest -Demographics:As of the census of 2000, there were 2,830 people, 1,200 households, and 784 families residing in the county. The population density was 2 people per square mile . There were 2,074 housing units at an average...
, Jefferson
Jefferson County, Montana
-National protected areas:*Deerlodge National Forest *Helena National Forest -Demographics:As of the census of 2000, there were 10,049 people, 3,747 households, and 2,847 families residing in the county. The population density was 6 people per square mile . There were 4,199 housing units at an...
, Judith Basin
Judith Basin County, Montana
-Demographics:As of the census of 2000, there were 2,329 people, 951 households, and 661 families residing in the county. The population density was -Demographics:...
, Missoula
Missoula County, Montana
-National protected areas:*Bitterroot National Forest *Flathead National Forest *Lolo National Forest *Rattlesnake National Recreation Area-Demographics:...
, Musselshell, Petroleum, Sanders
Sanders County, Montana
Sanders County is a county located in the U.S. state of Montana. As of 2010, the population was 11,413. Its county seat is Thompson Falls.-Geography:According to the U.S...
, Wheatland
Wheatland County, Montana
-Demographics:As of the census of 2000, there were 2,259 people, 853 households, and 540 families residing in the county. The population density was 2 people per square mile . There were 1,154 housing units at an average density of 1 per square mile...
, and Yellowstone
Yellowstone County, Montana
-National protected areas:* Nez Perce National Historical Park * Pompeys Pillar National Monument-Demographics:As of the census of 2000, there were 129,352 people, 52,084 households, and 34,219 families residing in the county. The population density was 49 people per square mile . There were...
. A state of emergency was declared in 51 Montana counties, cities, and Indian reservations. Flood waters from the Musselshell, Yellowstone, and several other Montana rivers flow into the Missouri River
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
and Mississippi River
Mississippi River
The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...
, exacerbating the 2011 flooding in states such as North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
and South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
.