Unlike with hurricanes, there are no ways to predict with relative certainty the arrival and ferocity of tornadoes.
But as officials reviewed preparations for the devastating tornadoes that ravaged the nation’s midsection Friday, many said that if anything went wrong before the storms hit, it was more a lack of response to warnings than a lack of information about the dangers.
Severe weather warnings began on Thursday and were issued throughout Friday in a host of states. Sirens woke residents in some areas late Friday and early Saturday to warn them that a tornado was near and that they should take shelter away from windows.
Gov. Asa Hutchinson of Arkansas on Sunday cited the “importance of the early warning system, the sirens, and taking action whenever you hear that.” In his state, one person died at a nursing home, a comparatively low death toll that Mr. Hutchinson called “a miracle.”
In Tennessee, where three people were killed, Gov. Bill Lee said at a news conference on Saturday that the toll was not higher because “people were prepared.”
“There was a very strong warning effort in many of the communities,” Mr. Lee said. “The residents of these communities were notified of the danger and notified of the imminence of these storms and, in many cases, we know that there were significant evacuations in the communities.”
Of course, even good preparation can’t negate the capriciousness of volatile and unpredictable storms. But meteorologists were issuing warnings to residents early on Friday across the six states where tornadoes appeared to touch down. In Kentucky, the hardest-hit state, forecasters said on Thursday and throughout Friday that severe weather was likely Friday night.
In Mayfield, Ky., where dozens died at a candle factory, workers who survived began to ask why they had been left to work inside the building when everyone knew that severe weather was coming.
Workers at the candle factory described hearing sirens on and off throughout the night. The tornado hit after a day of increasingly urgent warnings — by 3 p.m., the local National Weather Service office in Paducah, Ky., said that “several strong tornadoes” were “likely.” And by 8 p.m., the agency said people needed to have a “shelter-in-place plan.”
Isaiah Holt, 32, was on his shift in the wax and fragrance department when he heard sirens. A little more than a day later, on Sunday, he was in a hospital bed in Nashville, aching from a bruised lung and broken ribs and worrying about his brother, who also worked at the factory. His brother had been showered with bricks when the building collapsed.
Mr. Holt questioned whether the company should have kept people working after tornado warnings were issued. “They should have just canceled,” he said.
For some structures, warnings were not enough to prevent damage.
In Edwardsville, Ill., home to an Amazon warehouse where six people were killed, a tornado watch was in effect by midafternoon, and it became a tornado warning before 9 p.m. local time, with radar capturing the destructive tornado not long after.
At the Amazon facility, workers sheltered in two places. An Amazon spokesperson, Kelly Nantel, said that “the company calculated that about 11 minutes elapsed between the first warning of a tornado and when it hit the delivery station.”
One of the two areas was “directly struck by the tornado,” she said.