(WNCN) — Ever wonder how a major city on the coast gets everyone out when a hurricane is coming?

WGNO meteorologist Scot Pilie dives into contraflow and storm surge — often the greatest threat to life and property from a tropical storm or hurricane.

Also, WAVY meteorologist Jeff Edmondson talks about how a network of buoys surrounding the United States keeps us safe during hurricane season.

Join CBS 17 meteorologist Brian Hutton Jr., along with Pilie and Edmondson for episode six of Tracking the Tropics.

About storm surge

Storm surge is an abnormal rise of water generated by a storm, over and above the predicted astronomical tides.

Storm surge should not be confused with storm tide, which is defined as the water level rise due to the combination of storm surge and the astronomical tide.

This rise in water level can cause extreme flooding in coastal areas particularly when storm surge coincides with normal high tide, resulting in storm tides reaching up to 20 feet or more in some cases.

In the past, large death tolls have resulted from the rise of the ocean associated with many of the major hurricanes that have made landfall.

Hurricane Katrina in 2005 is a prime example of the damage and devastation that can be caused by surge. At least 1500 persons lost their lives during Katrina and many of those deaths occurred directly, or indirectly, as a result of storm surge.

What about contraflow?

Contraflow is when vehicles travel in the opposite direction of a lane’s normal traffic flow.

This occurs during an event like a hurricane evacuation, when all traffic lanes move toward inland safety and away from the Gulf Coast.

A hurricane evacuation lane is an extra-wide shoulder that is converted into an active thru lane in order to increase capacity during an emergency.

A short explanation on the buoy network

Wind, wave, and other marine data collected by the NOAA are detected by moored buoys in the Atlantic and Pacific oceans.

Parameters reported by the buoys include air temperature and pressure, wind speed and direction, wind gust, and sea surface temperature.

The buoys also report wave data, usually including wave height, wave period, and wave spectra.