The report suggests people had heard the sirens go off before, understood storms to be common during the spring, and had become desensitized to what they really meant.
The first siren did provoke residents to seek more information, either through televised reports, social media or seeing the storm itself.
Once the tornado sirens were activated a second time at 5:38 p.m., people recognized something was up and took shelter.
For the National Weather Service, this represents what the report calls a "credibility problem" for storm sirens - many people ignore them. That was true during two deadly tornado outbreaks in 2008 and was true in Joplin.
One idea is to add tiers to the warning system so people can distinguish a severe storm and a deadly emergency.
The report acknowledged that even people who took shelter in the appropriate places died while others who drove into the storm survived.
2) Pay attention to tornado watches
Although the report found most people know severe weather is common during spring, a majority of residents had no idea there was a threat of severe weather on May 22.
The report gives forecasters praise for anticipating the threat of severe weather more than 48 hours before the tornado, but makes no mention of what was shared with the general public in the days leading up to May 22.
Here's a rough timeline of the language the Storm Prediction Center was using:
Friday May 20: The SPC calls for slight risk of severe thunderstorms for a broad area from Texas to the Great Lakes. The forecast includes the following language about southwest Missouri: isolated supercells...a couple of which may be capable of producing tornadoes.
Saturday May 21: The SPC holds the severe weather threat at 30% for southwest Missouri. Saturday afternoon, the forecast includes a threat of very large hail.
Sunday May 22 7:55 a.m.: Joplin is upgraded to a moderate risk of severe weather. The forecast includes a 10% chance of an EF-2 to EF-5 tornado.
1:06 p.m.: The SPC issues a Mesoscale Discussion for southwest Missouri that includes, "although low level shear is a bit marginal, it will be more that sufficient for tornadoes given extreme instability."
1:30 p.m. The SPC and the National Weather Service issue a tornado watch.
While emergency managers and television meteorologists had the information, particularly the Sunday morning upgrade to a moderate risk of severe weather, the report does not delve into what those agencies and media outlets did with the information and how much of that advance knowledge was disseminated to the public.
3) The May 22 tornado was unpredictable, even to the experts
As much as the report praised forecasters for "recognizing the tornado potential of the storm," even as late as Sunday morning, meteorologists were more concerned about large hail and were not expecting big tornadoes.
It's common as major severe weather threats emerge for the National Weather Service to hold conference calls with emergency managers and the media. The NWS only organizes the calls when forecasters are pretty sure there will be damaging tornadoes or widespread wind damage. Everyone find them valuable because it puts them on a higher alert and in turn, insures their communications to the public have a greater sense of urgency. When NWS forecasters arrived at work on May 22, forecasters did not see enough of a tornado threat to justify a conference call.
Even as the tornado was forming, forecasters could not keep up with what was happening. The report states that was the result of a) the speed at which the tornado formed and b) how quickly and by what method the radars in Springfield and Tulsa were viewing the storm.
Two citations explain more:
Velocity data was obscured on KSGF [Springfield's radar] upstream of Joplin near a critical warning decision point and KINX [Tulsa's radar] velocity data was obscured over Joplin during the height of the tornado event.
Limited scans at lowest elevation slices during this time impacted the WFO's ability to quickly ascertain the magnitude of the tornado.
Essentially, Springfield and Tulsa's radars were scanning the storm using a method that allows them to collect data from distant storms. But that method spends the data back slightly slower and does not provide as many data points as other methods.
Better protocols for using that method is one many recommendations the report makes.