Kevin Myatt is The Roanoke Times' weather columnist.

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The aerial photos from Greensburg, Kan., are surreal.

The images wouldn't look much different if an atomic bomb had been set off over the southwest Kansas town.

But the death toll was not that of a nuclear attack: 10 people died in the town of 1,500.

How is that possible? How could so few have perished in such hugely catastrophic winds, likely well over 200 mph? How could so few have died in the mile-and-a-half swath of utter chaos and devastation in what is believed to be the most powerful tornado to strike a populated area in the United States in eight years?

If you want to invoke divine intervention, I have no objection. When I am near tornadoes, I am praying.

But there are also some things we've learned about tornadoes over the past few decades that have helped dramatically reduce death tolls, even in extreme events like the monster that essentially erased a town.

The residents of Greensburg had about 20 minutes' warning that a tornado was on the way.

Meteorologists with the National Weather Service could peer inside the brutal thunderstorm with Doppler radar and see the rapid rotation capable of producing a tornado. The storm was also closely monitored by both storm spotters -- local people assigned to observe and report the activity of severe storms -- and storm chasers -- people from various places, local and far away, following the storm for a variety of reasons, official and unofficial.

The reports that came back from the spotters and chasers confirmed what the weather service meteorologists were seeing on radar. This is often called "ground truth."

Many tornado warnings are issued each year for counties that do not experience a confirmed tornado. Once upon a time, a visual sighting of a tornado was required for a warning; often, those warnings came far too late.

Taking advantage of Doppler radar's ability to detect rotation inside a storm, tornado warnings are now issued when rotation becomes intense and tight enough to suggest a storm may produce a tornado. Even during this area's infrequent tornado warnings, you may have heard "Doppler radar indicated a storm capable of producing a tornado ... " or some similar language.

As a result, warnings are often issued before an actual tornado has formed. Sometimes the rotation indicated by radar may be intense, but does not spawn a tornado.

Tornado warnings are usually issued for entire counties. Even when there is an actual tornado on the ground, it only affects a relatively narrow swath within the county.

So, because some warned counties don't have tornadoes at all, and other warnings are issued for tornadoes that don't affect the vast majority of a county, most people perceive that nearly all tornado warnings are false alarms.

To emphasize the seriousness Friday night, the National Weather Service took an additional step in the case of Greensburg: It put out what is known as a "tornado emergency" warning. This kind of warning, rarely issued, includes much more stern language indicating a large, dangerous tornado has been observed on the ground and is definitely moving toward a specific location.

Most people in Kansas know what to do when a tornado is headed their way. They live with tornadoes year in and year out. Many have basements or cellars to retreat to, and those who don't know to get into an interior room, get as low as possible and cover up with something.

The combination of technological advances, trained observation, adequate warning and residents' knowledge and preparation probably saved scores if not hundreds of lives.