Wichita ? Not one person was killed in the United States by a tornado in April, May or June, for the first time since record-keeping started in 1950. Those three months are normally the peak tornado season, but weather officials say this has been an unusual year.

In fact, for the first time on record, not a single tornado formed in Oklahoma during May. “Tornado Alley” – as defined by the federal Storm Prediction Center – starts in central Texas and stretches north across Oklahoma, Kansas, Nebraska and South Dakota.

Historically, tornadoes kill an average of 52 people a year in the three peak months.

This is the second straight year, so far, that Kansas has recorded no tornado fatalities. Last year’s zero came despite a record number of tornadoes.

The absence of fatalities is not just a matter of climactic coincidence, said Chance Hayes, warning coordination meteorologist for the Wichita office of the National Weather Service.

“I’ve got to think it’s an educational issue,” Hayes said. “We have a consistent message we’re trying to get across to the public, and I can’t help but think it’s actually working. At least, that’s what I want to deduce out of the lack of fatalities.”

The combination of improved technology – such as more sophisticated radar – and more effective communication of storm threats among the weather service, media and emergency management offices is having a measurable impact, Hayes said.

A study published last month in the journal Weather & Forecasting calculated that new radars installed by the National Weather Service in the 1990s are saving nearly 80 lives a year that would otherwise be lost to tornadoes, The Associated Press reported.

The new equipment has allowed forecasters to issue warnings for 60 percent of tornadoes, up from 35 percent before the instruments were installed. In addition, the average lead time for warnings rose from 5.3 minutes to 9.5 minutes.

The previous low mark for tornado deaths around the nation in April through June was one in 1992. There were 17 fatalities in that period last year and 43 in 2003.