At the Storm Prediction Center in Norman, Oklahoma last week,
Corey mead, the lead forecaster was already tracking the early stages of the storm system that would devastate Joplin.
"We don't fully understand how tornadoes form..."
But mead, a 17 year veteran of the National Weather Service, says forecasting has improved significantly. He says:
"We can actually anticipate the potential for those types of storms several days out. But the exact locations and timing of more significant tornado threats - sometimes we don't know up until just a few hours leading up to the events."
Through this date last year, 506 tornadoes were reported in the U.S. This year, it's already more than double that...1151.
"This is just remarkable from a meteorological point of view."
Super Storms, says professor Stan Gedzelman are formed by an instability in the air that usually occurs in the spring:
"Sunday's instability - and the instability of the storms that hit Tuscaloosa is as large - just about as large as I have ever seen."
Gedzelman sees nothing strange in the weather pattern this year. But year to date, tornadoes have killed more than 500 people... That's seven times the average, making this the deadliest season in more than half a century.
"Did the warning system fail us?"
"The warning system was absolutely as good as it could be."
In fact, Joplin residents were given at least 20 minutes warning, when studies have shown that warnings of just 6 to 15 minutes reduce expected fatalities by more than 40%.
"It's really remarkable the accuracy of the forecasts. It's just that the level of destruction is - is beyond belief."
It's rare for tornadoes of this force to form at all, and rarer still for them to find population centers like Tuscaloosa and now, Joplin.