During the later days of August and throughout all of September 2010, the Porter area received excessive amounts of rain. Nearly 15 inches of rain fell within Porter and areas south during this time, leaving the ground soaked and completely saturated. In Porter itself the ground felt like a sponge, and simply mowing your lawn with a riding lawn tractor would leave divots in the yard that would soon "pop" back out after a day or so. During the week of September 20, it was reported on www.portermn.org that the town was fairing well thus far and even after a very wet spring and summer, basements in Porter were not seeing any water with the August and September rains.

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On September 21 it was reported that the Yellow Medicine River in Porter was running swiftly, but no more than 1 to 2 feet higher than normal flow. It was then on the afternoon of September 22 that it began to rain very heavy. By the morning of September 23 it was reported that the Yellow Medicine River had risen nearly 8 feet overnight. By noon on Wednesday the City's sanitary sewer system failed, putting raw sewage into Porter resident's basements, but to worsen matters the Yellow Medicine River also spilled its banks on Porter's south side and water began rushing into the old city dikes and filling a garage of a home built on the old dike.

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As sandbagging began it was noted that all three retention dams south and west of Porter were full to capacity with both Porter Lake (Dillon Pond) south of Porter and Lake John west of Porter discharging water over the emergency spillways. By 2:00 MNDOT was stopping and directing traffic on the west side of Porter as water rushed through the old skunk creek, which is typically nothing more than a drainage ditch that rarely has running water, rushed with heavy currents and spilled its banks flooding the west part of the Porter Elevator and then running over Highway 68 at Prairie Avenue with a heavy current.

 

As the day went on the Yellow Medicine River continued to rise and started to breach the levies on Porter's east side. Water began to come up into the yards at SMI where a temporary levee construction and sandbagging took full-force. SMI loaded valuable equipment in their buildings and yards onto flat bed semis to protect anything they could from the rising water. Levee breaches were also reported behind residences on Sunrise Avenue as water spilled over the levees from the river and began threatening those homes.

 

In an initial report to the FEMA it was reported that nearly $200,000 in damage was being claimed in city of Porter. Cleanup continued in Porter for weeks and months to follow the flood.