An instant later there was thunder so loud people called our newsroom saying something had exploded.
Some called 9-1-1, sure their houses took a direct hit from lightning (they did not) and car alarms suddenly went off in neighborhoods around that part of the Portland metro area.
Thunder is powerful stuff. And it starts with lightning, every single time. In this case the lightning was seen from Sherwood to Clackamas and the thunder slammed Raleigh Hills, Beaverton, Multnomah Village and other parts of SW.
How Lightning Causes Thunder
The image here shows the start: a lightning bolt can be up to 50,000 degrees Fahrenheit. It suddenly heats the air to as much as 18,000 degrees and that air next to the bolt explodes out (and eventually cools and races back in to some degree) This exploding (expanding) and contracting air creates the sound we know as thunder.
By the way, you can tell how far lightning is from you by counting as soon as you see the flash. One-one-thousand, two-one-thousand and so on. Every five seconds is a mile of distance. So if you count to five before hearing thunder, the lightning is one mile away. If you count to ten, the lightning is two miles away.You should wait at least 20 minutes after the last thunder you hear or lightning you see before heading out again.
In this case–if you were lucky (in weather guy terms) or unlucky (the way everyone else sees it) enough to be in Beaverton it was flash-boom…just that fast! The lightning was right on top of you!