What is a Storm?
The meteorological definition of a storm is a wind measuring 10 or higher on the Beaufort scale (a measurement that relates wind speed to observed conditions at sea or on land). In practical terms this means a wind speed of 24.5 m/s (89 km/h, 55 mph) or more.
Extreme storms can bring heavy rain, strong wind, hail, thunder and lightning (which in turn can start wildfires). If the weather conditions are severe enough there is even the possibility a storm could present as a tornado, waterspout or cyclone. Depending on season and local geography, some storms can last up to a week. Regional and seasonal severe weather phenomena can include blizzards, snowstorms, ice storms, and even dust storms.
Why storms are considered Emergencies
Severe storms can disrupt essential services and agriculture, cause major property damage, personal injury and loss of life.
Heavy Rainfall may result in destructive flooding, and is still considered a threat for people living inland. Flash flooding in urban areas, defined as a rapid rise in water levels, can occur quickly due to intense rainfall. See Councils flooding page for more detail on that type of emergency.
High Winds can be strong enough to be dangerous to those caught in them. Winds of 33 m/s (119km/h, 74mph) or more can destroy buildings and turn debris, such as signs, roofing material, siding and small items left outside into missiles.
Storm surge and large waves pose the greatest threat to life and property along the coast. Storm Surge is an abnormal rise of water generated by a storm's winds. The destructive power of storm surge and large battering waves can result in loss of life, buildings destroyed, beach and dune erosion and road and bridge damage along the coast. Storm surge can travel several miles inland. In estuaries and wetlands salt water intrusion endangers public health and the environment. Storm surge is made worse when storms combine with the natural astronomical tide.