An Inside Look at the National Weather Service's Storm Surveying Process

Mar 8, 2017

Have you ever been curious about the cleanup efforts that go on after a severe weather event, like a tornado? Nick Gilmore recently got a look behind the scenes of the surveying process that the National Weather Service goes through following a storm and filed this report.

Tornado outbreaks can be utterly devastating, with cleanup efforts that can stretch on for sometimes years after the event occurs. Before the cleanup can begin, however, the National Weather Service has to determine how strong the tornado was for a myriad of reasons, one of which is insurance claims.  

James Morrow, a meteorologist with the National Weather Service office in Blacksburg, says the process is extensive.

A home damaged by an EF-3 tornado last February in Evergreen, VA. Just like other National Weather Service employees across the nation with every weather event of that magnitude, local authorities had to go through an extensive surveying process before cleanup could begin.
Credit National Weather Service Blacksburg

“We see the damage, we look for clues to tell us whether or not a tornado was responsible or did just straight-line winds from a strong thunderstorm cause wind damage. Once we determine a tornado did cause it from those clues, that’s when we go into, ‘Alright, how strong were the winds that went in this?’”  

From there the process gets complicated. NWS employees have to determine a destroyed structure’s type and how well the structure was built before the tornado occurred. Those metrics help determine the storm’s wind speed at that point, which in turn helps give the tornado a strength rating on the enhanced-Fujita, or EF,  scale.

To make matters worse, the surveyors can sometimes disagree on the well-being of a building before a storm and have to complete the entire survey process for each destroyed building; something that becomes incredibly difficult in situations where multiple tornadoes have occurred in a single area.

The Weather Service has begun using new technology to help cut down on the length of the surveying process.
Credit National Weather Service

Thankfully, the Weather Service has started to implement new technology to help make the process smoother. One such technology that is currently being considered? Drones:

“Especially in remote areas like Southwest Virginia tends to have, you just can’t get to places to see some of the damage. Even if we go off-roading, we can only go a certain distance before we lose resources such as internet connectivity. You can cover a lot more ground in a lot less time using a lot less resources with just a simple flyover.”

In addition, the NWS has developed an app that allows for the surveying process to be done electronically – dramatically reducing the time it takes to complete one survey and move on to the next.