Northwest Iowa — A severe thunderstorm system passed through northwest Iowa early on Saturday morning and left some damage in its wake.
By the look of the radar echoes, the storm system was very long, stretching from southern Nebraska, nearly all the way to North Dakota in some places. It was moving generally to the northeast.
In our area, the National Weather Service’s Storm Prediction Center issued a severe thunderstorm watch at 3:10 a.m. for Lyon and Sioux counties and a county or two either side of the rivers that make up the western border of Iowa, but not including Osceola or O’Brien counties.
Nearly an hour later, at 4:03 a.m., the National Weather Service in Sioux Falls issued a severe thunderstorm warning for western Lyon County and western Sioux County, as well as eight other locations in the tri-state area. They said the main hazard of the storm was 60-mile-per-hour wind gusts.
At about 4:30 a.m., a storm downed some trees and blew off some shingles in Hawarden. A few minutes later, the winds were measured at 57 miles per hour a mile south-southwest of Hawarden.
At 4:45 a.m., the weather service issued a severe thunderstorm warning for Lyon, Osceola, Sioux, and northwestern O’Brien counties, as well as six other locations. Again, the main threat appeared to be 60-mile-per-hour wind gusts.
About seven minutes later, multiple large tree limbs were reported broken in Rock Valley, and four minutes later, large tree limbs were found down in Hull.
At 5:05 a.m., a thunderstorm wind gust was clocked at 53 miles per hour in Orange City.
The next report from the National Weather Service is of thunderstorm wind damage in Little Rock at about 5:20 a.m., where it was reported that 10-inch diameter tree limbs and power lines were damaged.
At 5:31 a.m., the weather service issued a severe thunderstorm warning for Osceola and O’Brien counties as well as eight other locations near the Minnesota and Iowa border. Again, the main threat appeared to be 60-mile-per-hour wind gusts.
Then, at 5:49 a.m., there was a report of 3-inch tree limbs broken a mile east of Rock Valley.
After that point, the storm system seems to have left only rain as it passed through the area. Sheldon recorded a half inch of rain, and Rock Rapids had 0.57 of an inch.
