Weak tornado wrought light damage
While last Friday’s tornado in western Spokane County was relatively weak by tornado standards, it was still powerful enough to toss a trampoline 200 feet into the air and suck the door off a barn, weather service officials said Monday.
The twister touched down for just a few minutes northwest of Fairchild Air Force Base. At least seven eyewitnesses were interviewed and the path of the tornado was examined by a National Weather Service meteorologist.
Ken Holmes, the meteorologist who conducted the investigation, gave the tornado an F0 rating under the Fujita Tornado Damage Scale, meaning it carried winds of no greater than 72 mph and caused only light damage. Under the scale, the most severe tornado is an F5 with winds in excess of 261 mph.
Holmes said the tornado touched down twice and held contact with the ground for a few minutes during each touchdown. It covered a distance of about 200 to 300 yards at a width of 50 to 75 feet. He estimated the top wind at 70 mph.
In the path of the tornado was a large trampoline that was tossed skyward into overhead power lines. The power lines ignited the fabric on the trampoline, causing it to catch fire. The frame landed in a field, Holmes said.
Air pressure from the twister was so low that it created a sucking force as it passed a barn, pulling its doors outward. One door was ripped off and another door was bent. Shingles on a residential roof were torn off and tossed aside in a pattern consistent with a tornado, Holmes said. Some small trees were torn off and broken.
One of the eyewitnesses was Holmes’ son, Leigh Holmes, who was traveling on U.S. Highway 2. He telephoned his father on a mobile phone when he spotted the tornado. That allowed Holmes, who was off duty at the time, to get to the scene within minutes, he said.
“It was an exciting night,” Holmes said.
Along with the twister, the cellular-type thunderstorm dropped pea-sized hail that covered the ground four to eight inches in depth in some places.
Tornados are unusual in Washington, occurring on an average of once a year statewide. The last tornado in Spokane County came in 1997 in the northern part of the county. A hail stone from that storm was nearly the size of a man’s fist, Holmes said.
The last tornado to strike inside Spokane came on May 30, 1980, in the northwest part of the city.
Thunderstorms pummeled the Spokane area throughout the day on Friday. From 10 a.m. to midnight, the weather service recorded 1,031 cloud-to-ground lightning strikes in the region.
Spokane International Airport, the city’s official weather monitoring station, had 2.19 inches of rain, and had one of the heaviest reports for rainfall in the region. The three-day rain total from Thursday through Saturday was nearly 3 inches at the airport.
Other monitoring sites had less rain on Friday. Deer Park recorded a half inch. Coeur d’Alene had an inch. Davenport had only .03 inches.
Friday’s downpours essentially ended Spokane’s precipitation deficit of about two inches since Jan. 1. Now, the city has had normal precipitation of about 7.5 inches through Sunday. The month of May by itself is 2.27 inches ahead of normal in Spokane.
Elsewhere, Friday’s thunderstorms were blamed for one possible house fire and damage at Agilent Technology’s plant at Liberty Lake, Holmes said.
The storms also caused a rapid rise in Hangman Creek, which discharged a large volume of muddy water but did not reach flood stage, Holmes said.