A thunderstorm that brought strong, swirling winds through northeast Oregon and southeast Washington Thursday did not produce any tornadoes, said the National Weather Service.
Although there were reports of rotating clouds, none were close enough to the ground to form a twister, said NWS forecaster Douglas Weber. Any upward or rotating wind was caused by friction between the wind and the ground or by the wind interacting with shelf clouds.
“(A shelf cloud) works like the front spoiler of your car — it pushes air up and over the lip and then drops the air back down behind,” Weber said.
A strong gust ripped through Pendleton at 6:15 p.m. when a cold front collided with warmer air, said forecaster Rob Brooks. The gust — which downed power lines and trees in Pendleton — was clocked at 55 mph at the Eastern Oregon Regional Airport and 79 mph in Helix, but it could have been stronger in other areas.
“It was a gust front,” Brooks said. “Winds picked up here the same time (they) picked up in Hermiston. Usually when people see something protruding from the clouds and heavy winds their first assumption is it’s a tornado.”
The weather service did not detect any funnel clouds, either. And although the clouds were low, they needed to be 1,000-2,000 feet closer to the ground to produce a tornado.
“A tornado is defined as a rotating column of air that extends from the base of the cloud to the (ground) surface,” Weber said. Strong winds could also have formed by the collision of warm air and cold rain.
Contact Chris Rizer at firstname.lastname@example.org or 541-966-0836.
This story originally appeared in East Oregonian.