1964 Northwestern Montana Floods - 50-Year Anniversary
Heavy rain began falling on snow and saturated soils throughout northwestern
Montana on the morning of June 7, 1964. Twenty-four hours of rain added
water to streams that were already running high from seasonal snowmelt. The
storm resulted in one of the most devastating floods in Montana's recent
history on both sides of the Continental Divide.
The Flathead River west of the Divide and the Dearborn, Sun, Teton, and
Marias Rivers east of the Divide carried record-breaking flows causing
wide-spread flooding. Local areas near rivers in Glacier National Park
and Waterton Lakes National Park that flow north to Hudson Bay also
Gibson Dam, on the Sun River remained intact despite overtopping. However,
on the Blackfeet Reservation, Swift Dam on Birch Creek and a dam on Two
Medicine River both were breached, quickly releasing large amounts of water.
People in the narrow valleys downstream from these structures had very little
time to escape the walls of flood water.
Sun River overtopped Gibson Dam when flood waters poured into
the reservoir upstream. The dam was designed to overtop, and
remained standing during the duration of the high flows.
General area of flooding during June 1964 and locations of current
USGS streamgages within the area.
How bad was it?
Twenty-eight people perished as a result of the flood waters in Birch and
Two Medicine Creeks; ultimately 30 people lost their lives in the floods.
Nearly 350 were injured, and about 8,700 received shelter and food from
the Red Cross. Total damage in Montana was estimated at $55 million, and
damages totaled more than $1 million in Canada (1964 dollars).
Badger Creek washes out U.S. Highway 89 Bridge.
Will these rivers flood again?
The map to the right shows that flood waters inundated areas far beyond
the Flathead River channel near Kalispell. Similar broad swaths of flood
waters also inundated parts of the Blackfeet Indian Reservation, Great
Falls, Choteau, and St. Mary. The 1964 floods on the Flathead, Sun, Teton,
and Marias Rivers are the largest in recorded history.
Floods bigger than the "100-year" event have occurred, and likely will occur
again. In an effort to better understand how frequently large floods occur,
USGS hydrologists are studying recorded streamflow data from streamgages in
and near the flooded areas as well as searching for clues about ancient
floods in tree rings, tree scars, boulders, and sediments along river
channels. Contact your local floodplain manager or call the Montana
Department of Natural Resources National Floodplain Insurance Program
Coordinator at (406) 444-6654 for more information to learn more about what
you can do to minimize damage and loss of life in case of a flood.
Who can I contact for more information?
For more information, contact Katherine Chase at (406)457-5957 or
Areal extent of floodwaters from the Flathead River during the
1964 flood. (Excerpt from Boner and Stremitz, 1964)
- Boner, F.C., and Stremitz, Frank, 1964, Floods of June 1964 in Northwestern
Montana: U.S. Geological Survey Water-Supply Paper 1840-B, 242 p.
- Parrett, Aaron, 2004, Natural Disaster, The 1964 Flood on the Blackfeet
Indian Reservation: Montana Historical Society.
Where to get more information: