After major weather-related disasters, the National Weather Service conducts a “Service Assessment” to understand what can be learned and what can be improved with regard to their forecasts and warnings.
The NWS just released its Joplin Service Assessment pertaining to the storm that killed 162 on May 22.
Several of their key findings include (my words in bold, assessment language in italics):
False Alarms of Severe Storms are a Real Problem
It was common in the interviews to hear residents refer to storms always blowing over and missing Joplin, or that there seemed like there was a protective bubble around Joplin, or ―there is rotation all the time, but never in Joplin…
Sounding Sirens for Severe Thunderstorm Warnings Caused Complacency
the perceived frequency of siren activation (false alarms) led an overwhelming number of participants to become desensitized or complacent to this method of warning. Many noted that they hear sirens all the time[sirens] go off for dark clouds, they are bombarded with [sirens] so often that we don‘t pay attention, the sirens have gone off so many times before, sirens are sounded even for thunderstorms, and all sirens mean is there is a little more water in the gutter.
Because People Want to “Confirm the Threat for Themselves” – the Invisible Nature of the Rain-Wrapped Tornado Misled People into Believing the Siren Was Sounding for a Severe Thunderstorm Warning.
While searching for additional information concerning the severe weather threat constitutes ―taking an action,‖ the actions many residents described taking were not the immediate life- saving measures desired with the issuance of a tornado warning. In most cases, these life-saving actions, or the decision to find shelter, were associated with additional extraordinary risk signals. This was generally achieved in different ways, including:
a. Physical observation of the environment (seeing the tornado approach). While significant numbers of people actually did this, the approach was complicated by having a ―rain-wrapped‖ tornado that made the tornado more difficult to recognize until it was very close. There were numerous accounts of people running to shelter in their homes just as the tornado struck, despite significant advance warning of the risk.
The report confirms my recommendations that sirens should only be sounded in extraordinary circumstances (tornado) and then only in the areas directly at risk. The multicounty siren activations in areas like St Louis lead to complacency and the opposite public response from what emergency management would like.
To individuals, take shelter when the warning is issued. Don’t run outside trying to figure out the threat.