COZAD — A complex of thunderstorms caused damage to the city of Cozad during the overnight hours of Sunday, Aug. 11 and Monday Aug. 12. Damage was primarily caused by straight line winds caused by a bow echo which moved along the Nebraska and Kansas state line.
According to National Weather Service Hastings meteorologist Jordan Thies, an expansive complex of thunderstorms moved through the south central region of the state during the overnight hours.
During the early afternoon Sunday, storms began to form off the Front Range in Colorado and began to track eastward. Several of these storms became supercells and went on to produce tornadoes. Most occurred in Colorado, but at least one was reported near Dundy.
These storms started to congeal and formed a larger complex of storms during the evening hours. Around 9 p.m. a storm system known as a bow echo was starting to take shape along the state line. This type of system is known for causing damage through severe straight line winds.
Thies said a bow echo forms in a line of thunderstorms under the right conditions, the downdrafts of these individual storms begin to congeal and form what is known as a cold pool. Through other processes, a pressure imbalance builds and the line of storms begins to accelerate.
The radar return given by this storm system looks similar to an archer’s bow. Thies said a positive feedback loop is formed by these types of systems, the faster the storms move, the faster the straight line winds are.
Cozad was in the path of the northern edge of this bow echo. Wind speeds measured around the Cozad area ranged from 55 to 60 mph. Thies said there was a preliminary report of a gust of 81 mph on the north side of town.
These winds led to dozens of downed trees and several power lines. Thies said most of this damage occurred between 11:50 p.m. at 12:10 a.m.
Rainfall across the Dawson County area averaged around an inch to an inch and a half, Thies said he wouldn’t be surprised if rainfall amounts were up to two inches between Gothenburg and Cozad.
Thies said Cozad wasn’t the only area impacted by the bow echo, the southern edge of the complex impacted Rooks and Phillips Counties in Kansas.
Bow echoes are fairly typical for July and August, as the atmosphere supports these types of storms during the later summer months said Thies.
Dawson Public Power District received 63 calls from the Cozad area about power outages which occurred from the storm, said Manager of Customer Service Marsha Banzhaf. Overall they received 260 calls from their whole area.
These power outages were caused primarily by lightning, tree damage and downed lines, said Banzhaf. As of Monday morning there were still a few outages, which DPPD crews were working on. Banzhaf said she expected by noon on Monday that all outages will have been addressed.