Defining the derecho
I heard a TV weather announcer use the term "derecho" in a story about the bad storms that went through the mid-Atlantic and some Midwest states about a month ago. What is that?
A derecho (pronounced deh-RAY-cho, it's a Spanish word meaning "straight ahead") is a damaging windstorm that is associated with a line of severe thunderstorms. When storms form near a stationary front, they can drag down high winds from the air above the storm through cold downbursts, spawning the high winds of a derecho.
It can be as destructive as a tornado, though its winds come in a straight line instead of rotating.
A derecho can last for hours and travel hundreds of miles with winds of 100 mph or more. They are most common in May, June, July and August in the United States.
The June 29 derecho swept across the mid-Atlantic states as far west as Chicago, more than 700 miles, killing more than 20 people and leaving 5 million homes without power for days.
Dr. Jeff Masters, director of meteorology for wundergound.com, said on a recent segment of National Public Radio's All Things Considered that during the derecho, "we had over 30 thunderstorms with wind gusts of 80 miles per hour. … It's kind of the equivalent to having 30-plus weak tornadoes on the ground."
Remember the March 1993 superstorm that ravaged Central Florida for six hours? That was a derecho. It spawned five tornadoes in the Tampa Bay area and massive flooding along the gulf coast and killed almost 50 people in the state.
Blue headlights, pros and cons
Are blue headlights really any better than those the rest of us use?
Experts say the blue xenon lights are an improvement over the standard halogen car headlights in the following ways:
• Visibility. Drivers can see the road better in the dark and in low-visibility conditions.
• Longevity. The xenon lights last two to three times longer than standard headlights. And because they don't use wire filaments, they are more energy efficient as well.
• Brightness. The xenon lights are up to three times brighter than the standard halogen lights.
• Intensity. The xenon lights are stronger and highlight a more distinct image.
Those are all advantages for the driver of the car with the xenon lights. But what about the drivers approaching the lights from the other direction? The most common complaint about the lights is that their brightness can be a distraction. Some car manufacturers have responded to that by adding technology to angle the lights slightly.
Xenon lights are also very expensive, and are usually seen as part of a premium package on pricier cars.