Tornado threats typically fade when the sun sets, but meteorologists say Friday's tornado didn't form until well after dark.
The supercell thunderstorm that produced the wedge-shaped tornado in Kiowa County continued to spawn tornadoes for four hours and nearly 100 miles.
"The environment never changed," said Chris Bowman, a meteorologist with the Wichita office of the National Weather Service. "You were able to maintain a very favorable tornado-producing environment all the way into the overnight hours."
Supercell thunderstorms feed off the instability created by the sun's heating of the atmosphere, meteorologists said Friday. But the Kiowa County storm used two key ingredients to stay strong well after midnight.
A low-level jet stream allowed it to tap into heat from upper levels of the atmosphere, and warm, moist air flowed in from the southeast all night to feed the storm.
"That was one heck of a storm," said Matt Gerard, a meteorologist with the Dodge City branch of the weather service.
Meteorologists are surveying the damage to learn how long the Greensburg tornado was on the ground and where it first touched down. That will also help meteorologists determine the tornado's enhanced Fujita rating -- the EF1 to EF5 designation often mentioned by forecasters.
As the tornado -- estimated at times to be a mile wide or more -- moved through Kiowa County, its northeasterly track seemed to be taking it clear of Greensburg.
"Our initial thought was that it would graze the southeastern edge of Greensburg, or perhaps miss the town entirely," Gerard said.
But as tornadoes start to weaken, he said, it's not unusual for them to make a left turn -- and that's just what this tornado did. The northerly turn took it into the heart of Greensburg.
As it began to fall apart north of the town, a second strong tornado formed and barreled northeast toward Trousdale and Hopewell.
"It was one of those classic, cyclic supercells," said Michael Lacy, a weather service meteorologist in Dodge City. "One tornado would develop, mature, and then bend to the north as it weakened" and then another tornado would develop.
"That happened over and over."
Storm spotters reported seeing at least one rope tornado rotating around the wedge tornado before it struck Greensburg, Gerard said, and it's possible multiple tornadoes were on the ground at the same time farther north along the storm's track.
The last tornado produced by the supercell touched down just south of Claflin shortly after 1:30 a.m., Bowman said. That's more than four hours of nighttime tornadoes from a storm that just didn't want to quit.
"It was amazing to see that," Gerard said. "It just kept on going."