Tornado warnings may create own risks

FILE - In this Friday, May 31, 2013, file photo, a man stands on top of his car as it is flooded on S. May Avenue near SW 25th in Oklahoma City. For decades, weather researchers have worked to give people as much warning as possible before a tornado or hurricane hits so that residents have time to protect themselves from nature's sometimes violent fury. But experts acknowledge there is some debate over whether increasing lead time is always a good thing (AP Photo/The Oklahoman, Sarah Phipps) LOCAL STATIONS OUT (KFOR, KOCO, KWTV, KOKH, KAUT OUT); LOCAL WEBSITES OUT; LOCAL PRINT OUT (EDMOND SUN OUT, OKLAHOMA GAZETTE OUT) TABLOIDS OUT

OKLAHOMA CITY — The average tornado warning in the 1980s went out only after a twister was on the ground. Continuing advances in storm prediction have since enabled forecasters to warn people before a funnel cloud is upon them, giving them precious time to seek shelter.

Our better understanding of the nature of tornadoes such as those that have ripped through Oklahoma several times over the past month, killing dozens of people and injuring hundreds more, has still saved countless lives. And our further understanding of such violent weather patterns will no doubt save even more.

Some experts, though, acknowledge there is debate about whether there can be too much advance warning of tornado strike, and if this could lead people to take foolish risks such as trying to dart across town to pick up a loved one or taking to the open road to try to outrun a violent storm.

“There’s a great philosophical discussion about what constitutes the ideal lead time,” said Greg Carbin, a warning coordination meteorologist for the National Weather Service’s Storm Prediction Center in Norman, Okla. “The more lead time the better, but the flip side of that is that accuracy and certainty in our predictions usually decrease with lead time.”

Over the last five years, residents in the U.S. have been given an average lead time of 13 minutes between the issuance of a tornado warning and a confirmed tornado on the ground. That’s a 17-minute increase from the 1980s, when tornado warnings were typically issued four minutes after a funnel had been spotted, said Lans Rothfusv, who is deputy chief of the warning research and development division at the National Severe Storms Laboratory in Norman.

Rothfusv credited the change to advancements in technology.

So, is there a “sweet spot” or an ideal amount of warning time?

“For years we’ve been looking at this from the physical science side — better radars and better science, but we’re at this interface where nature and humans intersect,” he said. “What we’re getting to is realizing we need to understand better how people respond to warnings. Maybe we could give people one hour. We need to know what the response may be.”