Omaha, Neb. - Stages on the Missouri River at Bismarck began rising at noon
on Friday in response to the first major outbreak of cold weather this
winter.
"Each winter during the freeze-in period, the stage at Bismarck typically
rises 5 to 7 feet over a short period of time due to ice formation on the
river," said Jody Farhat, Chief of the Corps of Engineers' Missouri River
Water Management office in Omaha. "To accommodate this large increase in
stage, we reduce releases from Garrison in advance of the cold weather to
provide sufficient channel capacity in the Bismarck area."
Releases from Garrison were reduced on Tuesday, January 10 from 23,000 cfs to
20,000 cfs in anticipation of the frigid weather and ice formation. On
Friday, with significant floating ice on the river, the stage in the Bismarck
area began to rise from a stage of 4.5 feet reaching 11.16 feet by early
Saturday evening. Last winter the river rose from a stage of 6.5 feet to
nearly 12 feet during the freeze-in, which occurred a month earlier than this
year. Flood stage for the Missouri River at Bismarck is 16 feet.
Although stages at the primary river gages at Bismarck and Schmidt are within
the normal range for the freeze-in period, stages at some intervening areas
are higher than seen in previous years. Saturday evening, the NWS issued a
flood warning for ice jam flooding for east central Morton and southwestern
Burleigh Counties until further notice.
The ice pads flowing on the Missouri River have been collecting south of
Bismarck. From the Huff area to just downstream of the Heart River, the
surface of the river is filled with stationary ice chunks. Additional ice
from upstream continues to expand the ice cover on the river. Although the
stage increase at the Bismarck gage has been similar to the gage records for
past river freezes, the river levels downstream of the gage are higher than
would typically occur for the stage at the gage. Keith Demke, P.E., Director
of Utility Operations for the City of Bismarck stated, "We are seeing water
levels in the South Bismarck storm water channel that correspond to what we
would expect with a stage of 12.5 to 13 feet at the Bismarck gaging station."
The river will continue to be monitored by local officials, the State Water
Commission and the Corps. Residents along and near the river should remain
vigilant in case the situation worsens.
Once a stable ice cover is established, stages typically begin to decline and
releases from Garrison dam can gradually be increased without causing the
river to rise. This is due to the smoothing of the underside of the ice and
the channel bottom, which creates a more efficient channel. "Releases from
Garrison will remain at 20,000 cfs for the foreseeable future and will not be
increased until ice conditions permit," said Farhat. "If conditions allow,
releases may reach 27,000 cfs by February."