The Missouri River at Fort Benton reached its highest level in over 10 years on Wednesday morning, following an ice jam downstream in Loma.
The US Geological Survey (USGS) gauge recorded an eight-foot water level rise from Tuesday afternoon through Wednesday morning.
The river crested at 9.67 feet at around 9:30 a.m. before quickly receding Wednesday afternoon.
While this is the highest the river has been in some time, this level is four feet shy of flood stage which is 13.5 feet.
According to the USGS, Front Street in Fort Benton floods at 13.5 feet. Main, Franklin and Washington streets become inundated at 18.5 feet.
The Missouri River at Fort Benton has only reached flood stage eight times since record-keeping began in 1891.
| Missouri River @ Fort Benton crest | Date | |
| 1 | 18.50 feet | June 6th, 1908 |
| 2 | 16.39 feet | February 9th, 1996 |
| 3 | 14.37 feet | January 12th, 1968 |
| 4 | 14.14 feet | January 11th, 1973 |
| 5 | 14.00 feet | January 15th, 1974 |
| 6 | 13.64 feet | January 30th, 1984 |
| 7 | 13.57 feet | June 5th, 1953 |
| 8 | 13.53 feet | January 18th, 1970 |
Temperatures have risen 50 to 60 degrees since the weekend in many parts of the state.
As temperatures warm above freezing, the ice breaks apart and begins to flow downstream.
In many cases, the ice becomes lodged in tight or curved portions of the river obstructing the flow of water completely.
Ice jams form and break unexpectedly causing flooding upstream or a sudden rush of water downstream, respectively.
The majority of ice jams in Montana occur in February and March.
Montana reports the largest number of ice jams and attributed deaths.
Riverfront property owners or homeowners with properties in floodplains should remain vigilant this time of year, especially during times of large temperature fluctuations.
