By Alexander Fisher, Esq
Volunteer, Disaster Accountability Project
In October, we began a series on the significant problems faced by the unregulated tornado siren system in Alabama and Missouri. This week the series continues with a discussion of how a lack of oversight has left emergency managers with different criteria for sounding tornado sirens.
Contrary to popular belief, tornado sirens do not automatically sound when a tornado warning is issued for an affected area. Instead, the decision to sound sirens generally sits with local county or municipal emergency managers. This has led to inconsistency among even neighboring counties in determining when to sound tornado sirens.
Some emergency managers activate tornado sirens whenever a severe thunderstorm warning is issued. Others activate the sirens when a severe thunderstorm warning is issued during a tornado watch. Some emergency managers sound the sirens as soon as a tornado warning is issued. Others do so only when there is spotter verification of a tornado or funnel cloud approaching the siren area.
The meteorological and emergency management community has begun to take notice of this problem. The National Weather Service (NWS), in its assessment of the Joplin tornado, found that “[f]or the vast majority of surveyed Joplin residents, the first risk signal for an imminent severe weather threat came via the local community siren system. As a result, there was a significant degree of ambiguity associated with the first alert regarding the magnitude of the risk, the seriousness of the warning, and its potential impact.”
In recognition of this problem, Rob Dale, a prominent meteorologist, developed the Workgroup for Warning Systems, which issued a “Best Practices for Outdoor Warning Sirens” on September 12, 2011. This best practices policy recommends standardizing tornado siren activation and only activating sirens in the following circumstances: (1) if the NWS issues a tornado warning for the area; (2) if there is no tornado warning but credible, trained weather spotters indicate a tornado is occurring or imminent in the area; or (3) when a severe thunderstorm warning is issued and associated wind gusts of greater than 75 mph have been confirmed.
An example can be found in Oklahoma, where all of the municipalities in the Oklahoma City Metro Area have agreed to a matching set of guidelines for tornado siren activation.
Without any regulatory structure in place, states have little ability to require emergency managers to abide by any form of standardized siren activation criteria, and widespread participation in any such system must be voluntary. With sirens providing such crucial and lifesaving warning services, states must quickly address inconsistent and potentially confusing siren activation criteria.