by Susan Van Cleaf & Aaron Brom
SUN PRESS NEWSPAPERS
Powerful straight line winds and rain from a bow echo system lashed through many Twin Cities metro area, including northwest Hennepin County and eastern Wright County, last weekend and the storm is leaving a legacy in its wake — minor to moderate flooding of the Crow River.
The National Weather Service (NWS) in Chanhassen Monday issued a flood warning for the South Fork of the Crow River at Delano and the Crow River at Rockford. The NWS predicted a 17.3 foot crest for Delano Friday, June 28, and an 11.6 foot crest for Rockford Saturday, June 29. Both river levels would be just a tad below moderate flood stage.
For Rockford an 11-foot river level would mean that low lying areas and some roads along the river would begin to experience flooding, according to the NWS. For Delano, a 17-foot water level might make it necessary to plug storm sewers to prevent river water from backing up onto city streets.
“Do not drive cars through flooded areas,” the NWS warned. “Turn around. Don’t drown.”
NWS hydrologists based the river forecast on rainfall that had occurred Friday, June 21 through Sunday, June 23. On average, rainfall in a wide spread area amounted to three to four inches, with localized amounts of six or more inches falling across the region.
“Rainfall amounts through 7 a.m. Tuesday (June 25) will average between one and one and a quarter inches,” the NWS said. “In addition, we are expecting another round of storms during the day on Tuesday and into Tuesday night. The forecast rainfall with that activity has not been included in forecasts. So additional rains could cause river levels to rise even higher than predicted.”
At 10 a.m., Monday, June 24, hydrologists measured the water level for the Crow River at Delano at 14.31 feet. They predicted that the river would reach minor flood stage of 16.5 feet on Wednesday, rise to 17.3 feet by Friday and drop below flood stage on Monday, July 1.
At Rockford, the Crow River was flowing along at 7.65 feet on Monday. The NWS predicted it would reach minor flood stage of 10 feet on Wednesday, crest at 11.6 feet on Saturday and begin to drop on Sunday.
Further downstream, in Hanover, St. Michael and Rogers, the river was not expected to flood as much as in Delano and Rockford. No serious damage was reported, but Albertville and St. Michael did have some flooding.
“On Saturday the St. Michael area received as much as 4 inches of rainfall in approximately at two hour period,” city administrator Steve Bot said. “This vast amount of rainfall in a short period of time taxed the city’s storm water system including all pipes, ditches, ponds, inlets, outlets, floodways, and emergency overflow areas.”
Bot said the system fortunately worked well as the city is not aware of any homes that directly flooded during this high intensity storm event. But many roadways, driveways, trails, and yards did become flooded for a period of time until the areas were able to drain down once rainfall stopped and the storm water system was able to catch up.
“Both on Sunday and (Monday), City of St. Michael Public Works Crews have been working to clear roadways and drainage inlets from storm debris,” Bot said. “Areas with the most amount of damage reported were also reviewed for potential future drainage improvements.”
In Albertville, city administrator Adam Nafstad said the amount of rain over such a short duration, coupled by the highly saturated soil conditions, produced flash flooding and resulted in localized street flooding and overtopping of several rear yard sediment ponds.
“The intersection of Barthel Industrial Drive an 54th Street NE experienced the greatest degree of flooding with water depths estimated to be approximately 2-feet at the intersection,” Nafstad said. “Three residents adjacent to the intersection have reported damaged to their basements.”
He said public works crews are working to ensure storm sewer inlets and culverts are open and draining, as well as, monitoring water levels of several ponds and ditches throughout the city, and that residents with questions or concerns are encouraged to call city hall at 497-3384.
Rogers Police Capt. Mike Miller said although the storm closed the Rockin’ Rogers Days carnival briefly Friday night, there were no serious damage reports or flooding.
In Corcoran, police chief Sean Gormley said there were no reports of widespread damage or floods, but that a tree fell into a house at 6603 Willow Dr. and caused a minor house fire. He did say there were numerous trees down.
Meanwhile, Xcel Energy estimated that more than 475,000 customers were affected by power outages due to storms on Friday night and Saturday morning. By Monday, power was restored to most customers, but some were still waiting.
The worst of the storm came right through the center of the metro, including Medina, Plymouth, Wayzata, Minnetonka, Golden Valley and Minneapolis.
The National Weather Service said that the storm had a bow-like signature on radar. This type of thunderstorm complex is capable of producing very strong straight line winds across a large area.
Last Friday’s storm produced a measured wind speed of 66 miles per hour at Buffalo. The NWS received reports of wind gusts as high as 69 miles per hour at the Crystal Airport, 40 miles per hour in Monticello, 50 miles per hour in Maple Grove, and 61 miles per hour at the Minneapolis-St. Paul airport.
Contact Susan Van Cleaf at email@example.com
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A large conifer died in an appropriate place, Holy Name Cemetery in Medina, during severe wind/rain storms Friday. The tree narrowly missed gravestones as it came in for a crash landing. (Sun staff photo by Susan Van Cleaf)
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The Medina city brush pile reached colossal proportions as residents dropped off branches and trees on Sunday. (Sun staff photo by Susan Van Cleaf)
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During last weekend’s storm, a landmark old tree in Delano landed in the Crow River just south of the Bridge Avenue bridge. The height of the swollen river was rising towards the bottom of the bridge on the way to a predicted crest of 17.3 feet for Friday, June 28. (Sun staff photo by Susan Van Cleaf)