17 foot crest predicted for Delano on Friday
Powerful straight line winds and rain from a bow echo system lashed through many western Twin Cities suburbs, including Medina, Rockford and Delano, 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, at noon on 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.
Rockford City Administrator Nancy Carswell said Monday that the city’s new levee protects downtown Rockford up to a 14 foot river level. “We’ll be on alert all week. We might do some sand bagging in low lying areas. If we need to, we can call for volunteer sand baggers.”
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.
Rain totals of one to four inches caused flash flooding in Rockford on County Road 20 near the Rockford Fire Station and in Delano, where water flowed over Highway 12 downtown. Flash floods also hit Minneapolis, Falcon Heights and Robbinsdale, where water flowed down the streets.
In Medina, winds measure at 52 miles per hour felled many large trees two to three feet in diameter and produced property damage. Several large conifers toppled at Holy Name Cemetery and narrowly missed gravestones.
Betty White was driving home to her house near Mooney Lake as the storm hit at 7:30 p.m. on Friday. Trees came down on each side of the road, forcing her to drive down the middle of the road. As she arrived home, a tree came down next to the end of her driveway. She missed being under the falling tree by less than a minute.
Trees also were down in Delano, New Brighton, Eden Prairie, Maple Plain, Loretto, Crystal, St. Louis Park. Delano lost an old landmark tree on River Street, when it broke off from its trunk and crashed into the Crow River, just south of the Bridge Avenue bridge.
Some storm damage was hidden. Residents struggled with flooded basements after losing power to their sump pumps.