The Minnesota River Valley experienced historic flooding last week and through the weekend, impacting communities like Granite Falls as well as the surrounding area. Flooding accelerated mid-week, rising 3.23 feet alone between Wednesday and Thursday. This rapid acceleration continued throughout the week, and by early Saturday morning, the river had reached its maximum crest of 893.52 feet above sea level. Although flooding this year was much higher than usual, it was still slightly below the 2011 level of 893.55 feet.
In fact, of the top 10 historic floods, six (including this year) occurred sometime after 1997. The growing rate of spring flooding can be attributed to several factors including human-create climate change (which creates more moisture in the air) and agricultural practices (such as tiling, which more efficiently moves water on fields to waterways).
Although flooding in the Granite Falls area was, overall, moderate, the river did breach the levy road north of town. Most of the water was re-routed through a backchannel rather than inundating residential areas. The river has already begun its slow retreat. The USGS river gauge at Granite Falls showed a reading of 892.03 feet on Tuesday morning, down slightly from 892.63 feet at the same time on Monday.
The river will occasionally crest and retreat during the next couple of weeks before returning to its pre-flood levels. The rate of retreat will largely depend on total rainfall and the rate of spring thawing. Both the city and county have been providing assistance during the flood. Sandbags were made available for residents who needed them, and the county was busy ensuring that flooded roads were monitored and if necessary closed.
Flooding along Highway 212 between Granite Falls and Montevideo has temporarily shut-down portions of the highway. It’s not clear when the road will reopen and motorists are strongly advised against driving through flooded roadways. As of Wednesday morning, the Minnesota River stood at 891.42, down slightly from 892.03 feet at the same time yesterday.
The NWS flood forecast currently predicts that this steady decline will continue, falling nearly three feet by next Tuesday. Again, this largely depends on rainfall and temperatures, though the NWS has been largely accurate in their forecasts so far this season.