The Perfect Storm Heavy precipitation, driven by strong winds, struck Vermillion and other areas of Clay County Monday night. The driver of this vehicle (above) negotiates through limited visibility on Vermillion�s Main Street during the height of the storm. Tuesday morning, citizens awoke to find heavy limbs snapped by the wind, and scores of trees blown over and in some cases uprooted by the severe weather. by David Lias If you�re a big fan of tracking weather phenomenon, Monday night�s climate in Clay County could be termed a perfect storm.
Tree, yard and home lovers in the community have a much less flattering description of the system that roared through Vermillion.
Rain poured down in heavy sheets, driven by winds that at times gusted to 70 miles per hour.
Small hail battered the city, but didn�t cause any significant damage.
The big culprit was the wind. An incredible number of the city�s most stately trees were no match to the forces of the storm.
Many lost large limbs. And several large trees were either uprooted or were snapped a few feet above the ground.
�It was a very, very impressive storm,� said Brad Temeyer, a meteorologist with the National Weather Service in Sioux Falls. �It started up in the northern portion of the county, east, northeast of Wakonda at about 7 p.m., and just pushed southward. It was moving very, very, very slowly.
�As we were seeing it on radar; it looked very impressive,� he said, �probably one of the best storms we�ve seen thus far all season.�
The weather service was expecting the storm to be a prolific hail producer, judging by radar images and other weather data.
After an initial blast of rain and wind, hail began to fall in the city. Most of it was about marble-sized, so it caused little to no damage. But, like the rain, it was both thick, and falling at high velocity, driven by strong winds.
The hail fell for approximately 15 minutes, nearly covering the ground with a blanket of white in some areas.
�It looks like we had wind gusts of up to 70 miles per hour causing the power poles to go in and out in Vermillion,� Temeyer said, �That was reported by an amateur weather spotter shortly after 8:30 p.m. Monday.�
At 9 p.m., the National Weather Service began receiving reports of flash flooding in the city.
�In addition to significant flooding in the town, there were several trees and houses that were damaged by water and wind,� Temeyer said.
The storm held together as it moved south, he added. Parts of Dixon County, south of Vermillion in Nebraska, reported four inches of rain hail the size of baseballs, and damage to vehicles, homes and other structures.
The Vermillion area received two to four inches of rain from the storm, according to the weather service.
Monday night�s storm was spawned by weak winds aloft, Temeyer said.
�It was rotating quite a bit, which is why it was able to support all of that hail, and the atmosphere was very unstable,� he said.
There was a warm layer of air aloft on Monday, Temeyer said, which inhibited storms from developing through the day.
�With very warm temperatures near the surface and high moisture values as well, the atmosphere was able to de-stabilize very significantly,� he said.